ABIOMED INC
S-3/A, 1997-10-10
SURGICAL & MEDICAL INSTRUMENTS & APPARATUS
Previous: CHUBB INVESTMENT FUNDS INC, 497, 1997-10-10
Next: EASTERN ENVIRONMENTAL SERVICES INC, 8-K/A, 1997-10-10



<PAGE>
 
    
 AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON OCTOBER 10, 1997     
                                                   
                                                REGISTRATION NO. 333-36657     
- -------------------------------------------------------------------------------
- -------------------------------------------------------------------------------
 
                      SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C. 20549
 
                                ---------------
                                
                             AMENDMENT NO. 1     
                                       
                                    TO     
                                   FORM S-3
                            REGISTRATION STATEMENT
                                     UNDER
                          THE SECURITIES ACT OF 1933
 
                                ---------------
                                 ABIOMED, INC.
            (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)
 
               DELAWARE                              04-2743260
    (STATE OR OTHER JURISDICTION OF               (I.R.S. EMPLOYER
    INCORPORATION OR ORGANIZATION)             IDENTIFICATION NUMBER)
 
                             33 CHERRY HILL DRIVE
                         DANVERS, MASSACHUSETTS 01923
                                (978) 777-5410
         (ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING
            AREA CODE, OF REGISTRANT'S PRINCIPAL EXECUTIVE OFFICES)
 
                                ---------------
                             DR. DAVID M. LEDERMAN
                     PRESIDENT AND CHIEF EXECUTIVE OFFICER
                                 ABIOMED, INC.
                             33 CHERRY HILL DRIVE
                         DANVERS, MASSACHUSETTS 01923
                                (978) 777-5410
           (NAME, ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER,
                  INCLUDING AREA CODE, OF AGENT FOR SERVICE)
 
                                ---------------
                                  COPIES TO:
       PHILIP J. FLINK, ESQUIRE               STEVEN C. BROWNE, ESQUIRE
    BROWN, RUDNICK, FREED & GESMER         TESTA, HURWITZ & THIBEAULT, LLP
         ONE FINANCIAL CENTER                      125 HIGH STREET
      BOSTON, MASSACHUSETTS 02111            BOSTON, MASSACHUSETTS 02110
            (617) 856-8200                         (617) 248-7000
 
                                ---------------
  APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC: As soon as
practicable after the effective date of this Registration Statement.
  If the only securities being registered on this Form are being offered
pursuant to dividend or interest reinvestment plans, check the following
box. [_]
  If any of the securities being registered on this Form are to be offered on
a delayed or continuous basis pursuant to Rule 415 under the Securities Act of
1933, other than securities offered only in connection with dividend or
interest reinvestment plans, check the following box. [_]
  If this Form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, check the following box and
list the Securities Act registration statement number of the earlier effective
registration statement for the same offering. [_]
  If this Form is a post-effective amendment filed pursuant to Rule 462(c)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering. [_]
  If delivery of the prospectus is expected to be made pursuant to Rule 434,
check the following box. [_]
       
       
  THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR
DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT
SHALL FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS
REGISTRATION STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH
SECTION 8(A) OF THE SECURITIES ACT OF 1933 OR UNTIL THE REGISTRATION STATEMENT
SHALL BECOME EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SAID
SECTION 8(A), MAY DETERMINE.
 
- -------------------------------------------------------------------------------
- -------------------------------------------------------------------------------
<PAGE>
 
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+INFORMATION CONTAINED HEREIN IS SUBJECT TO COMPLETION OR AMENDMENT. A         +
+REGISTRATION STATEMENT RELATING TO THESE SECURITIES HAS BEEN FILED WITH THE   +
+SECURITIES AND EXCHANGE COMMISSION. THESE SECURITIES MAY NOT BE SOLD NOR MAY  +
+OFFERS TO BUY BE ACCEPTED PRIOR TO THE TIME THE REGISTRATION STATEMENT        +
+BECOMES EFFECTIVE. THIS PROSPECTUS SHALL NOT CONSTITUTE AN OFFER TO SELL OR   +
+THE SOLICITATION OF AN OFFER TO BUY NOR SHALL THERE BE ANY SALE OF THESE      +
+SECURITIES IN ANY STATE IN WHICH SUCH OFFER, SOLICITATION OR SALE WOULD BE    +
+UNLAWFUL PRIOR TO REGISTRATION OR QUALIFICATION UNDER THE SECURITIES LAWS OF  +
+ANY SUCH STATE.                                                               +
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
                  
               SUBJECT TO COMPLETION, DATED OCTOBER 10, 1997     
 
                         [ABIOMED LOGO APPEARS HERE]

                               2,400,000 SHARES
 
                                  COMMON STOCK
   
  Of the 2,400,000 shares of Common Stock offered hereby, 2,250,000 shares are
being offered by ABIOMED, Inc. ("ABIOMED" or the "Company") and 150,000 shares
are being offered by the Selling Stockholders. See "Principal and Selling
Stockholders." The Company will not receive any of the proceeds from the sale
of shares by the Selling Stockholders. On October 9, 1997, the last reported
sale price of the Company's Common Stock, as reported on the Nasdaq National
Market, was $22.125 per share. See "Price Range of Common Stock." The Company's
Common Stock is traded on the Nasdaq National Market under the symbol "ABMD."
    
                                  -----------
 
        THE COMMON STOCK OFFERED HEREBY INVOLVES A HIGH DEGREE OF RISK.
                    SEE "RISK FACTORS" BEGINNING ON PAGE 6.
 
                                  -----------
 
THESE  SECURITIES HAVE NOT BEEN APPROVED  OR DISAPPROVED BY THE SECURITIES  AND
 EXCHANGE  COMMISSION   OR  ANY  STATE  SECURITIES  COMMISSION  NOR   HAS  THE
  COMMISSION OR  ANY STATE SECURITIES COMMISSION PASSED UPON  THE ACCURACY OR
   ADEQUACY  OF THIS  PROSPECTUS. ANY  REPRESENTATION TO  THE CONTRARY IS  A
    CRIMINAL OFFENSE.
 
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
<TABLE>
<CAPTION>
                                             UNDERWRITING                         PROCEEDS TO
                             PRICE TO        DISCOUNTS AND      PROCEEDS TO         SELLING
                              PUBLIC          COMMISSIONS        COMPANY(1)      STOCKHOLDERS
- ---------------------------------------------------------------------------------------------
<S>                      <C>               <C>               <C>               <C>
Per Share..............
- ---------------------------------------------------------------------------------------------
Total (2)..............
</TABLE>
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
(1) Before deducting expenses payable by the Company, estimated at $400,000.
(2) The Company has granted the Underwriters a 30-day option to purchase up to
    an additional 360,000 shares of Common Stock solely to cover over-
    allotments, if any. See "Underwriting." If such option is exercised in
    full, the total Price to Public, Underwriting Discounts and Commissions and
    Proceeds to Company will be       ,        and       , respectively.
 
                                  -----------
   
  The Common Stock is offered by the Underwriters as stated herein, subject to
receipt and acceptance by them and subject to their right to reject any order
in whole or in part. It is expected that delivery of such shares will be made
through the offices of BancAmerica Robertson Stephens, San Francisco,
California, on or about      , 1997.     
 
                                                                  UBS SECURITIES
BANCAMERICA ROBERTSON STEPHENS     
 
                  The date of this Prospectus is       , 1997
<PAGE>
 
                   BVS-5000(R) BI-VENTRICULAR ASSIST SYSTEM




                                                     
                                                  THE BVS-5000 PNEUMATIC
[PHOTOGRAPH OF THE ITEMS DESCRIBED                CONSOLE WITH TWO SINGLE-USE
IN THE CAPTION]                                   BVS BLOOD PUMPS MOUNTED ON A
                                                  BEDSIDE STAND. THE BVS-5000
                                                  PROVIDES A PATIENT'S FAILING
                                                  HEART WITH FULL CIRCULATORY
                                                  ASSISTANCE WHILE ALLOWING
                                                  THE HEART TO REST, HEAL AND
                                                  RECOVER ITS FUNCTION.     
 
  CERTAIN PERSONS PARTICIPATING IN THIS OFFERING MAY ENGAGE IN TRANSACTIONS
THAT STABILIZE, MAINTAIN OR OTHERWISE AFFECT THE PRICE OF THE COMMON STOCK OF
THE COMPANY, INCLUDING STABILIZING BIDS, SYNDICATE COVERING TRANSACTIONS AND
THE IMPOSITION OF PENALTY BIDS. FOR A DISCUSSION OF THESE ACTIVITIES, SEE
"UNDERWRITING."
 
  IN CONNECTION WITH THIS OFFERING, CERTAIN UNDERWRITERS AND SELLING GROUP
MEMBERS OR THEIR AFFILIATES MAY ENGAGE IN PASSIVE MARKET MAKING TRANSACTIONS
IN THE COMMON STOCK ON THE NASDAQ NATIONAL MARKET IN ACCORDANCE WITH RULE 103
OF REGULATION M UNDER THE SECURITIES EXCHANGE ACT OF 1934. SEE "UNDERWRITING."
<PAGE>
 
  NO DEALER, SALES REPRESENTATIVE OR ANY OTHER PERSON HAS BEEN AUTHORIZED TO
GIVE ANY INFORMATION OR TO MAKE ANY REPRESENTATIONS IN CONNECTION WITH THIS
OFFERING OTHER THAN THOSE CONTAINED IN THIS PROSPECTUS, AND, IF GIVEN OR MADE,
SUCH INFORMATION OR REPRESENTATION MUST NOT BE RELIED UPON AS HAVING BEEN
AUTHORIZED BY THE COMPANY, ANY SELLING STOCKHOLDER OR ANY UNDERWRITER. THIS
PROSPECTUS DOES NOT CONSTITUTE AN OFFER TO SELL OR A SOLICITATION OF AN OFFER
TO BUY, ANY SECURITIES OTHER THAN THE REGISTERED SECURITIES TO WHICH IT
RELATES OR AN OFFER TO, OR A SOLICITATION OF, ANY PERSON IN ANY JURISDICTION
IN WHICH SUCH AN OFFER OR SOLICITATION WOULD BE UNLAWFUL. NEITHER THE DELIVERY
OF THIS PROSPECTUS NOR ANY OFFER OR SALE MADE HEREUNDER SHALL, UNDER ANY
CIRCUMSTANCES, CREATE ANY IMPLICATION THAT THERE HAS BEEN NO CHANGE IN THE
AFFAIRS OF THE COMPANY SINCE THE DATE HEREOF OR THAT THE INFORMATION CONTAINED
HEREIN IS CORRECT AS OF ANY TIME SUBSEQUENT TO THE DATE HEREOF.
 
                               ----------------
 
                               TABLE OF CONTENTS
 
<TABLE>   
<CAPTION>
                                                                          PAGE
                                                                          ----
   <S>                                                                    <C>
   Summary...............................................................   4
   Risk Factors..........................................................   6
   Use of Proceeds.......................................................  17
   Dividend Policy.......................................................  17
   Price Range of Common Stock...........................................  18
   Capitalization........................................................  19
   Selected Consolidated Financial Data..................................  20
   Management's Discussion and Analysis of Financial Condition and
    Results of Operations................................................  21
   Business..............................................................  26
   Management............................................................  40
   Certain Transactions..................................................  43
   Principal and Selling Stockholders....................................  44
   Description of Capital Stock..........................................  45
   Underwriting..........................................................  46
   Legal Matters.........................................................  50
   Experts...............................................................  50
   Available Information.................................................  50
   Incorporation of Certain Documents by Reference.......................  51
   Index to Consolidated Financial Statements............................ F-1
</TABLE>    
 
                               ----------------
 
  ABIOMED(R), ABIODENT(R) and the ABIOMED logo are registered service marks of
the Company. BVS(R), BVS-5000(R) and PerioTemp(R) are registered trademarks of
the Company. Angioflex(TM) and Heart Booster(TM) are trademarks of the
Company. Halimeter(R) is a registered trademark of Interscan Corporation. This
Prospectus also includes trademarks of companies other than the Company.
 
  As used herein, the term "ABIOMED" or the "Company" includes the Company and
its consolidated subsidiaries.
 
  References to "Common Stock" include "Rights" issuable pursuant to that
certain Rights Agreement entered into in August 1997 providing for the
delivery of a Right along with each share of Common Stock issued by the
Company. See "Description of Capital Stock."
 
                                       3
<PAGE>
 
                                    SUMMARY
 
  This Prospectus contains forward-looking statements which involve risks and
uncertainties. The Company's actual results could differ materially from those
anticipated in these forward-looking statements as a result of certain factors,
including those set forth under "Risk Factors" and elsewhere in this
Prospectus.
 
  The following summary is qualified in its entirety by, and should be read in
conjunction with, the detailed information and the Consolidated Financial
Statements and Notes thereto appearing elsewhere in this Prospectus.
 
                                  THE COMPANY
 
  ABIOMED, Inc. ("ABIOMED" or the "Company") is a leader in the research and
development of cardiac assist and heart replacement technology. The Company
developed, manufactures and sells the BVS-5000 ("BVS"), a temporary cardiac
assist device designed to provide a patient's failing heart with full
circulatory assistance while allowing the heart to rest, heal and recover its
function. The BVS is most frequently used in patients whose hearts fail to
immediately recover function following heart surgery. The BVS is the only
device that can provide full circulatory assistance approved by the United
States Food and Drug Administration ("FDA") as a bridge-to-recovery device for
the treatment of patients with reversible heart failure.
 
  The Company is developing a battery-powered totally implantable artificial
heart ("TAH") intended as a permanent replacement device to assume the full
pumping function of both the left and right ventricles of the heart. The TAH is
designed for use by patients with irreparably damaged hearts and at risk of
death due to acute myocardial infarction ("AMI"), chronic ischemic disease or
some form of end-stage congestive heart failure, but whose vital organs
otherwise remain viable. Among these combined groups, the Company believes that
approximately 60,000 patients per year could benefit from a heart replacement
device. The Company is devoting significant resources to accelerate the
development of the TAH with the goal to initiate clinical trials of the TAH by
the end of the year 2000. There can be no assurance that the Company will be
able to successfully complete pre-clinical testing of the TAH and receive FDA
approval to begin clinical trials of the TAH in a timely manner, if at all, or
that any market will develop for the TAH.
   
  The Company sells the BVS in the United States through direct sales and
clinical support teams. Its sales force focuses on sales to new customers,
while its clinical support group focuses on training and educating existing
customers in order to improve clinical outcomes and increase BVS blood pump
usage. The BVS is intended for use in any hospital performing open-chest
cardiac surgery, of which there are more than 900 in the United States. As of
September 30, 1997, the BVS had been purchased by over 275 medical centers in
the United States including many of the largest centers. The Company believes
that its installed base of customers provides an opportunity for reorders of
the single-use BVS blood pumps as well as a reference base to assist in selling
to new accounts.     
 
  The Company's goal is to be a leader in the development, manufacture and
marketing of mechanical cardiac assist and heart replacement devices that
address the varying needs of a wide range of patients. The Company is pursuing
a variety of strategies to pursue this objective, including accelerating the
development of the TAH, increasing market penetration of the BVS, maintaining
and enhancing its technological leadership and pursuing strategic relationships
to support its research and commercialization efforts.
 
  Since the Company's inception, United States government agencies,
particularly the National Heart, Lung and Blood Institute ("NHLBI"), have
provided significant support to the Company's product development efforts. The
Company seeks funding from third parties to support its research and
development programs and generally limits the use of its own funds until the
scientific risk is reduced. In addition, the Company intends to pursue
collaborative relationships to develop and commercialize the Company's non-
cardiac assist technologies.
 
  The Company is a Delaware corporation. The Company's principal offices are
located at 33 Cherry Hill Drive, Danvers, Massachusetts 01923. The Company's
telephone number is (978) 777-5410 and its fax number is (978) 777-8411.
 
 
                                       4
<PAGE>
 
                                  THE OFFERING
 
<TABLE>   
<S>                                            <C>
Common Stock Offered by the Company...........  2,250,000 shares
Common Stock Offered by the Selling               150,000 shares
 Stockholders.................................
Common Stock Outstanding after the Offering... 10,514,556 shares (1)
Use of Proceeds............................... For research and development,
                                               expansion of manufacturing
                                               capabilities and other general
                                               corporate purposes. See "Use of
                                               Proceeds."
Nasdaq National Market Symbol................. ABMD
</TABLE>    
 
                      SUMMARY CONSOLIDATED FINANCIAL DATA
                     (in thousands, except per share data)
 
<TABLE>   
<CAPTION>
                                                                      SIX MONTHS
                                                                        ENDED
                                  YEAR ENDED MARCH 31,              SEPTEMBER 30,
                          ----------------------------------------- --------------
                           1993     1994     1995    1996    1997    1996   1997
                          -------  -------  ------  ------  ------- ------ -------
<S>                       <C>      <C>      <C>     <C>     <C>     <C>    <C>
STATEMENT OF OPERATIONS
 DATA:
Revenues:
  Products..............  $ 1,709  $ 4,648  $6,893  $9,725  $12,311 $5,760 $ 9,324
  Contracts.............    1,736    2,027   2,337   3,118    4,151  1,754   3,680
                          -------  -------  ------  ------  ------- ------ -------
    Total revenues......    3,445    6,675   9,230  12,843   16,462  7,514  13,004
Costs and expenses:
  Cost of products......    2,042    2,211   3,289   3,921    5,361  2,123   3,438
  Research and
   development (2)......    2,097    2,431   2,464   3,218    3,833  1,781   3,654
  Selling, general and
   administrative.......    3,803    4,553   4,278   5,741    7,068  3,229   4,970
                          -------  -------  ------  ------  ------- ------ -------
    Total costs and
     expenses...........    7,942    9,195  10,031  12,880   16,262  7,133  12,062
                          -------  -------  ------  ------  ------- ------ -------
Income (loss) from
 operations.............   (4,497)  (2,520)   (801)    (37)     200    381     942
Interest and other
 income.................      604      537     449     528      535    256     417
                          -------  -------  ------  ------  ------- ------ -------
Net income (loss).......  $(3,893) $(1,983) $ (352) $  491  $   735 $  637 $ 1,359
                          =======  =======  ======  ======  ======= ====== =======
Net income (loss) per
 share..................  $ (0.60) $ (0.31) $(0.05) $ 0.07  $  0.10 $ 0.09 $  0.17
                          =======  =======  ======  ======  ======= ====== =======
Weighted average number
 of shares outstanding..    6,441    6,461   6,512   6,995    7,162  7,196   7,869
</TABLE>    
 
<TABLE>   
<CAPTION>
                                                         SEPTEMBER 30, 1997
                                                      ------------------------
                                                      ACTUAL  AS ADJUSTED (3)
                                                      ------- ----------------
<S>                                                   <C>     <C>
BALANCE SHEET DATA:
Cash, cash equivalents and short-term marketable
 securities.......................................... $24,312     $70,980
Working capital......................................  29,109      75,777
Total assets.........................................  36,348      83,016
Total stockholders' investment.......................  32,648      79,317
</TABLE>    
- --------
   
(1) Based on the number of shares outstanding as of September 30, 1997.
    Excludes 964,410 shares of Common Stock reserved for issuance upon the
    exercise of stock options outstanding as of September 30, 1997 at a
    weighted average exercise price of $10.81 per share. See Note 6 to
    Consolidated Financial Statements.     
(2) Research and development expenses include certain contract costs. See Note
    1(e) to Consolidated Financial Statements.
          
(3) Adjusted to reflect the sale of 2,250,000 shares of Common Stock offered by
    the Company hereby at an assumed public offering price of $22.125 per share
    and the application of the net proceeds therefrom after deducting the
    estimated underwriting discounts and commissions and offering expenses
    payable by the Company. See "Use of Proceeds" and "Capitalization."     
 
  Except as otherwise indicated, all information in this Prospectus assumes no
exercise of the Underwriters' over-allotment option.
 
                                       5
<PAGE>
 
                                 RISK FACTORS
 
  This Prospectus contains forward-looking statements which involve risks and
uncertainties. The Company's actual results could differ materially from those
anticipated in these forward-looking statements as a result of certain
factors, including those set forth in the following risk factors and elsewhere
in this Prospectus.
 
  In addition to the other information in this Prospectus, the following risk
factors should be considered carefully in evaluating the Company and its
business before purchasing shares of the Common Stock offered hereby.
 
DEPENDENCE ON BVS PRODUCT LINE; EARLY STAGE OF BVS MARKET DEVELOPMENT
   
  In the six months ended September 30, 1997 and the fiscal year ended March
31, 1997, sales of the BVS and related products and services represented more
than ninety percent of the Company's product revenues. The Company believes
that its dependence on the BVS product line is likely to continue for at least
the next several years, unless and until the Company successfully develops,
obtains regulatory approvals for and sells new products.     
 
  The market for the BVS continues to be in the early stage of development.
The Company has initially focused its marketing efforts on larger medical
centers and hospitals. The commercial success of the BVS will be dependent
upon both the Company's ability to sell the BVS to smaller hospitals and
medical centers, which generally have more limited financial resources, and
the increase of the use of the BVS at those medical centers and hospitals
which have purchased the systems. There can be no assurance that the Company
will be successful in marketing the BVS. Advances in medical technology,
biotechnology and pharmaceuticals may reduce the size of the potential markets
for the Company's products or render those products obsolete. Failure of the
Company to expand the market for and use of the BVS would have a material
adverse effect on its business, financial condition and results of operations.
See "Business--Marketing and Sales."
 
UNCERTAINTY OF PRODUCT DEVELOPMENT AND CLINICAL TRIALS
 
  The Company has developed and markets a limited number of products and
believes that its future success will in large part be dependent upon its
ability to develop and market innovative new products, such as the TAH. The
successful development of these products presents enormous challenges. The
Company must demonstrate that the TAH, which is being designed to assume the
full pumping function of both the left and right ventricles of the heart, can
operate effectively and reliably within a patient over an extended period. For
many years, the Company and others have been attempting to develop products
that meet these criteria and have not yet been successful. Before obtaining
regulatory approvals for the commercial sale of any of its products under
development, the Company must demonstrate through pre-clinical studies and
clinical trials that the product is safe and effective. Initial pre-clinical
testing of the TAH and other products being developed by the Company will be
conducted in simulated environments and animal models to demonstrate safety
and effectiveness over an extended period of time before they are permitted to
be clinically tested in humans. There can be no assurance that the Company
will be able to successfully complete pre-clinical testing of the TAH or other
products being developed by the Company and receive FDA approval to initiate
clinical trials of such products in a timely manner, if at all. Moreover, pre-
clinical trials may not be predictive of results that will be obtained in
clinical trials. Any significant delays in, or termination of, pre-clinical
trials of the Company's products under development would have a material
adverse effect on the Company's business, financial condition and results of
operations.
 
  Clinical trials for the Company's cardiac assist and heart replacement
products will be conducted with patients who are critically ill. During the
course of treatment, these patients may die or suffer other adverse medical
effects for reasons that may not be related to the product being tested but
which can nevertheless affect clinical trial results. A number of companies in
the medical device industry have suffered significant
 
                                       6
<PAGE>
 
setbacks in advanced clinical trials, even after promising results in earlier
trials. Clinical trials of the Company's TAH and other products under
development may be delayed or terminated as a result of many factors, and
there can be no assurance that such delays or terminations will not occur. One
such factor is the rate of enrollment of patients, which generally varies
throughout the course of a clinical trial and which depends on the size of the
potential patient population, the number of clinical trial sites, the
proximity of the patients to clinical trial sites, the eligibility criteria
for the trial and the existence of competitive clinical trials. The Company
cannot control the rate at which patients present themselves for enrollment,
and there can be no assurance that the rate of patient enrollment will be
consistent with the Company's expectations or be sufficient to enable clinical
trials of the Company's products under development to be completed in a timely
manner, if at all. Any significant delays in, or termination of, clinical
trials of the Company's products under development would have a material
adverse effect on the Company's business, financial condition and results of
operations.
 
  In addition, the Company's product development will be subject to numerous
other risks associated with new product development, including unanticipated
delays, expenses, technical problems or other difficulties that could result
in the abandonment or substantial change in the design, development and
commercialization of these new products. Given the uncertainties inherent with
product development and introduction, there can be no assurance that any of
the Company's products under development will demonstrate sufficient safety
and efficacy to obtain the requisite regulatory approvals, on a timely basis
and within budget, if at all, or that any of these products will be
commercially successful if such approvals are obtained. See "Business--ABIOMED
Products and Products under Development."
 
ANTICIPATED FUTURE LOSSES
   
  The Company plans to use its own resources to fund the further development
of the TAH in amounts significantly in excess of the funding provided under
the Company's development contract for the TAH with the NHLBI ("TAH
Contract"). The Company estimates that the development of the TAH, including
conducting pre-clinical and clinical studies and obtaining regulatory
approvals, will require substantial funds. Its spending under the TAH Contract
in the quarter ended September 30, 1997 exceeded the amount which the
government has currently appropriated for that contract, and the original
government appropriation schedule calls for no further appropriations for the
TAH Contract until October 1998. There can be no assurance that the government
will appropriate any additional amounts under the TAH Contract or any of the
Company's other government contracts on a timely basis, if at all. Even if and
when additional amounts are appropriated under the TAH Contract, the Company
believes that its total expenses to complete the development of the TAH will
significantly exceed the remaining TAH Contract amount. As a result, the
Company believes that it is likely that the Company will incur losses,
potentially as soon as the quarter ending December 31, 1997. The amount and
duration of these losses will depend upon a number of factors, including the
Company's ability to increase sales and profitability of its present products,
to develop and obtain regulatory approvals for new products and product
enhancements, and to successfully manufacture and market these new products
and enhancements, as well as the timing and extent of the Company's spending
related to product development and the timing of government appropriations
related to the Company's NHLBI contracts. See "Use of Proceeds" and
"Management's Discussion and Analysis of Financial Condition and Results of
Operations."     
 
COMPLEX MANUFACTURING; HIGH-QUALITY REQUIREMENTS
 
  The nature of the Company's products requires high-quality manufacturing.
The Company's manufacturing and quality testing processes and procedures are
highly dependent on the diligence and experience of the Company's personnel.
To the extent that the Company's manufacturing volumes expand or the Company
begins the manufacture of new products, this dependence on personnel will
likely increase. In addition, the manufacture of the blood contacting surfaces
of the Company's products requires a high degree of precision. These surfaces
are manufactured from polyurethane-based materials. The quality and
composition of polyurethane-based products can vary significantly based on
numerous factors including humidity, temperature, material content and air
flow during the manufacturing process. The Company's products also incorporate
plastic components for non-blood contacting surfaces. The Company relies on
third-party vendors to provide these components to the Company's
specifications. The Company is not able to fully inspect the quality of all
vendor supplied components and, therefore, relies on its vendors with respect
to the
 
                                       7
<PAGE>
 
quality of these components. Once the plastic-based components of the Company's
products have been assembled, accessibility for inspection is limited. If a
defect is detected in as few as one of the Company's products, or in one
component of a Company product, it can result in the recall or restriction on
sale of products. Once assembled, in most cases, the Company's blood contacting
components cannot be reworked for human use. The manufacturing lead times for
parts and assemblies, particularly the polyurethane-based components, can take
many weeks from the date that all materials and components are received by the
Company. In addition, vendor lead times for materials and components of the
Company's products vary significantly, with lead times for certain materials
and components exceeding six months.
 
  The Company is planning to expand its manufacturing facility for the BVS
during the next twelve months. There can be no assurance that the products
manufactured in the expanded facility will be manufactured at the same cost and
quality as the BVS is currently being manufactured. In addition, to the extent
that the Company's products under development have been manufactured, they have
been manufactured as prototypes with, at most, pilot-scale production. The
Company's products under development are likely to involve additional
manufacturing complexities and high quality requirements. There can be no
assurance that the Company will be able to increase production of the BVS or
manufacture future products, if developed and approved, in commercial
quantities on a consistent and timely basis, with acceptable cost and quality.
The inability to manufacture current and future products in sufficient
quantities in a timely manner, and with acceptable cost and quality, would have
a material adverse effect on the Company's business, financial condition and
results of operations. See "Business--Manufacturing."
 
RISK OF MARKET WITHDRAWAL OR PRODUCT RECALL
 
  Complex medical devices, such as the BVS and other of the Company's products
under development, can experience performance problems that require review and
possible corrective action by the manufacturer. Similar to many other medical
device manufacturers, the Company periodically received reports from users of
its products relating to performance difficulties they have encountered. The
Company expects that it will continue to receive customer reports regarding the
performance and use of the BVS. There can be no assurance that component
failures, manufacturing errors or design defects that could result in an unsafe
condition or injury to the patient will not occur. Certain of these failures or
defects have been deemed sufficiently serious by the Company to result in
recalls of products associated with certain manufacturing lots or containing
certain components, including a recall of certain BVS blood pumps initiated in
late 1996. Not all of the products subject to this recall have been returned to
the Company. Any product problems could result in market withdrawals or recalls
of products, voluntarily or required, which could have a material adverse
effect on the Company's business, financial condition and results of
operations. In addition, there can be no assurance that a product recall will
result in the recovery of all defective products or prevent customers from
using these products. The use of a defective product could result in injury to
a patient and significant liability to the Company which could have a material
adverse effect on its business, financial condition and results of operations.
See "Management's Discussion and Analysis of Financial Condition and Results of
Operations."
 
FLUCTUATIONS AND UNPREDICTABILITY OF OPERATING RESULTS
 
  The Company's annual and quarterly operating results have fluctuated and the
Company expects these fluctuations to continue. Significant annual and
quarterly fluctuations in the Company's results of operations may be caused by,
among other factors, the overall state of health care and cost containment
efforts, economic conditions in the Company's markets, the expense and timing
of the Company's development efforts for a particular product or product
enhancement, the timing of regulatory actions, the potential need to recall or
rework products from time to time, timing of government appropriations related
to the Company's research contracts and grants, the timing of or changes in
third-party reimbursement policies for the Company's products, the timing of
expenditures in anticipation of future sales, variations in the Company's
product mix and component costs, the availability of components, the timing of
customer orders, adjustments of delivery schedules to accommodate customers,
inventory levels of products at customers (including inventory at
 
                                       8
<PAGE>
 
distributors), changes in the government's funding policies under the
Company's existing contracts, pricing and other competitive conditions, and
the timing of the announcement, introduction and delivery of new products and
product enhancements by the Company and its competitors. Customers may also
cancel or reschedule shipments, and production difficulties could delay
shipments. The price for the BVS console is significantly higher than for the
single-use blood pumps. As a result, variations in the number and timing of
consoles sold have a disproportionate effect on the Company's revenues and
results of operations. The Company also believes that BVS sales may be
somewhat seasonal, with reduced sales in the summer months, reflecting
hospital personnel and physician vacation schedules. Beginning in fiscal 1998,
the Company anticipates potentially significant annual and quarterly
fluctuations in contract revenues and research and development costs
associated with the development of the TAH due to the need for additional
government appropriations under the TAH Contract and to increased levels of
Company spending. See "Management's Discussion and Analysis of Financial
Condition and Results of Operations."
 
MARKETS FOR PRODUCTS UNDER DEVELOPMENT UNPROVEN
 
  Most of the Company's products under development, including the TAH, are
targeting new and unproven markets. There can be no assurance that the TAH or
other products under development by the Company will gain any degree of market
acceptance among physicians, medical centers and third party payors, including
managed care organizations, even if necessary regulatory approvals and
reimbursement are obtained. As a result, it is likely that the Company's
evaluation of the potential markets for these products will materially vary
with time. In addition, the effective use of these products will likely
require development of new surgical techniques by well-trained physicians,
which will initially limit the market for the Company's products. Physicians,
patients and society as a whole may have ethical concerns or be reluctant to
accept medical devices designed to replace the heart. The timing and amount of
reimbursement, if any, by third-party payors for the use of these products, if
developed, will also have a significant impact on the market for these
products. Other companies may also introduce products or technologies which
will compete with these products, reduce the market for these products, or
render these products obsolete. There can be no assurance that the Company
will be able to market successfully any of its products under development, if
and when these products are developed. Failure to do so would have a material
adverse effect on the Company's business, financial condition and results of
operations. See "Business--Marketing and Sales."
 
DEPENDENCE ON KEY PERSONNEL; RISKS ASSOCIATED WITH GROWING NUMBER OF EMPLOYEES
 
  The Company is highly dependent on the principal members of its scientific,
sales, and management staff, the loss of whose services could have a material
adverse effect on the Company's business, financial condition and results of
operations. Competition among medical device companies for highly skilled
scientific, sales and management personnel is intense. There can be no
assurance that the Company will be able to attract and retain all personnel
necessary for the development of its business. Failure to do so could have a
material adverse effect on its business, financial condition and results of
operations.
   
  The Company has recently experienced a significant increase in the number of
its full-time employees, from 79 at April 1, 1996 to 166 at September 30,
1997. Moreover, the Company intends to continue to add a significant
additional number of employees to support its development and expanding
manufacturing, marketing and sales efforts. The expansion of the Company's
personnel has placed additional demands upon, and may significantly strain,
the Company's management, financial systems and other resources. There can be
no assurance that the Company will be able to successfully manage its growing
number of employees. Failure to do so would have a material adverse effect on
the Company's business, financial condition and results of operations.     
 
COMPETITION AND TECHNOLOGICAL CHANGE
 
  Competition in the cardiac assist market is intense and subject to rapid
technological change and evolving industry requirements and standards. Many of
the companies developing or marketing cardiac assist products
 
                                       9
<PAGE>
 
have substantially greater financial, product development, sales and marketing
resources and experience than the Company. These competitors may develop
superior products or products of similar quality at the same or lower prices.
Moreover, there can be no assurance that improvements in current or new
technologies will not make them technically equivalent or superior to the
Company's products in addition to providing cost or other advantages. Other
advances in medical technology, biotechnology and pharmaceuticals may reduce
the size of the potential markets for the Company's products or render those
products obsolete.
 
  The BVS is the only device that can provide full circulatory assistance
approved by the FDA as a bridge-to-recovery device for the treatment of
patients with reversible heart failure. However, the Company is aware of at
least one other company, Thoratec Laboratories Corporation, seeking approval
of a temporary cardiac assist device to address this market. Approval by the
FDA of products that compete directly with the BVS would increase competitive
pricing and other pressures and could have a material adverse effect on the
Company's business, financial condition and results of operations.
 
  The Company is aware of other artificial heart development efforts in the
United States, Canada, Europe and Japan. A team comprised of Pennsylvania
State University and 3M Corporation, Inc. has been developing a heart
replacement device for many years with significant NHLBI support. There are a
number of companies, including Thermo Cardiosystems, Inc. and Novacor, a
division of Baxter International, Inc., which are developing permanent cardiac
assist products, including implantable left ventricular assist devices
("LVADs") and miniaturized rotary ventricular assist devices, that may address
markets that overlap with those targeted by the Company's TAH.
 
  The Company's customers frequently have limited budgets. As a result, the
Company's products compete against the broad range of medical devices for
these limited funds. The Company's success will depend in large part upon its
ability to enhance its existing products and to develop new products to meet
regulatory and customer requirements and to achieve market acceptance. The
Company believes that important competitive factors with respect to the
development and commercialization of its products include the relative speed
with which it can develop products, establish clinical utility, complete
clinical testing and regulatory approval processes, obtain reimbursement and
supply commercial quantities of the product to the market. There can be no
assurance that the Company will be able to compete successfully or that
competition will not have a material adverse effect on the Company's business,
financial condition and results of operations. See "Business--Competition."
 
GOVERNMENT REGULATION
 
  Clinical testing, manufacture and sale of the Company's products and
products under development, including the BVS and the TAH, are or will be
subject to regulation by the FDA and corresponding state and foreign
regulatory agencies. Noncompliance with applicable requirements can result in,
among other things, fines, injunctions, civil penalties, recall or seizure of
products, total or partial suspension of production, failure of the government
to grant pre-market clearance or pre-market approval for devices, withdrawal
of marketing approvals and criminal prosecution. The FDA also has the
authority to request repair, replacement or refund of the cost of any device
manufactured or distributed by the Company.
 
  Any devices, including the BVS, that are manufactured or distributed by the
Company pursuant to FDA clearances or approvals are subject to pervasive and
continuing regulation by the FDA and certain state agencies. Manufacturers of
medical devices for marketing in the United States are required to adhere to
the FDA's Quality System Regulation and must also comply with Medical Devices
Reporting requirements that a firm report to the FDA any incident in which its
product may have caused or contributed to a death or serious injury, or in
which its product malfunctioned and, if the malfunction were to recur, it
would be likely to cause or contribute to a death or serious injury. Labeling
and promotional activities are subject to scrutiny by the FDA and, in certain
circumstances, by the Federal Trade Commission. Current FDA enforcement policy
prohibits the marketing of approved medical devices for unapproved uses. The
Company is subject to routine inspection by the FDA and certain state agencies
for compliance with the Quality System Regulation and Medical Device Reporting
requirements, as well as other applicable regulations.
 
                                      10
<PAGE>
 
  In addition, the FDA requires that manufacturers of certain devices,
including the BVS, conduct postmarket surveillance studies after receiving
approval of a Pre-Market Approval ("PMA") application. The primary purpose of
required postmarket surveillance is to provide an early warning system to
alert the health care community to any potential problems with a device within
a reasonable time of the initial marketing of the device. Postmarket
surveillance provides clinical monitoring of the early experiences with the
device once it is distributed in the general population under actual
conditions of use.
 
  The Company is also subject to regulation in each of the foreign countries
in which it sells its products. Many of the regulations applicable to the
Company's products in these counties are similar to those of the FDA. The
Company believes that foreign regulations relating to the manufacture and sale
of medical devices are becoming more stringent. The European Union has adopted
regulations requiring that medical devices comply with the Medical Device
Directive by June 15, 1998, which includes ISO-9001 and CE certification. The
Company's BVS currently has German MedGV approval but is not yet certified for
ISO-9001 compliance. The Company is working to obtain ISO-9001 and independent
CE certification for its BVS facility. There can be no assurance that the
Company will obtain such certification in a timely manner, if at all. Unless
ISO and CE certification are obtained, the Company's sale of the BVS into the
European Union may be restricted. Many manufacturers of medical devices,
including the Company, have often relied on foreign markets for the initial
commercial introduction of their products. The more stringent foreign
regulatory environment could make it more difficult, costly and time consuming
for the Company to pursue this strategy for new products.
 
  Any FDA, foreign or state regulatory approvals or clearances, once obtained,
can be withdrawn or modified. Delay in the Company obtaining, or inability of
the Company to obtain and maintain, any necessary United States or foreign
clearances or approvals for new or existing products or product enhancements,
or cost overruns resulting from these regulatory requirements, would have a
material adverse effect on the Company's business, financial condition and
results of operations. See "Business--Government Regulation."
 
RELIANCE ON GOVERNMENT CONTRACTS
   
  The Company generally relies on external funding for its basic research and
development, primarily through government research contracts and grants. Such
funding has been obtained for the initial development of most of the Company's
current products and products under development. In particular, in September
1996, the Company was awarded by the NHLBI a four-year $8.5 million extension
to its TAH Contract, and in September 1995 the Company was awarded a five-year
$4.3 million contract from the NHLBI for the development of the Company's
Heart Booster. As of September 30, 1997, the Company's total backlog of
government contracts and grants was $8.7 million. Such contracts and grants
are not expected to be sufficient to commercialize the underlying products,
and for certain products, including the TAH, the cost of product development
in excess of the contract value is expected to be significant. The Company's
strategy is to continue to seek government contracts and grants to support
development efforts. Funding for the Company's government research and
development contracts is subject to government appropriation, and all of these
contracts contain provisions which make them terminable at the convenience of
the government. There can be no assurance that the government will not
terminate or reduce or delay the funding for any of the Company's contracts.
In addition, there can be no assurance that the Company will be successful in
obtaining any new government contracts or further extensions to existing
contracts. A significant delay or reduction of funding under the Company's
government contracts could have a material adverse effect on the Company's
business, financial condition and results of operations. See "Management's
Discussion and Analysis of Financial Conditions and Results of Operations" and
"Business--ABIOMED Products and Products under Development" and "--Strategic
Relationships."     
 
                                      11
<PAGE>
 
DEPENDENCE ON LIMITED SOURCES OF SUPPLY
 
  The Company relies on outside vendors to supply certain components used in
the BVS and in its products under development. Certain of the components of
the BVS are supplied by sole source vendors or are custom made for the
Company. From time to time, suppliers of certain components of the BVS have
indicated that they intend to discontinue, or have discontinued, making such
components. In addition, certain of these components are supplied from single
sources due to quality considerations, costs or constraints imposed by
regulatory authorities. There are relatively few additional sources of supply
for such components and establishing additional or replacement suppliers for
such components cannot be accomplished quickly and may require FDA approval.
In the past, certain suppliers have announced that, due to government
regulation or in an effort to reduce potential product liability exposure,
they intend to limit or terminate sales of certain products to the medical
industry. There can be no assurance that, if such an interruption were to
occur, the Company would be able to find suitable alternative supplies at
reasonable prices or would be able to obtain requisite regulatory approvals in
a timely manner, if at all. Similarly, when and if the Company reaches the
clinical testing stage of its products under development, it may find that
certain components become more difficult to source from outside vendors due to
the product liability risk perceived by those vendors. The Company's inability
to obtain acceptable components in a timely manner or to find suitable
replacements at an acceptable cost would have a material adverse effect on the
Company's business, financial condition and results of operations. See
"Business--Manufacturing."
 
FUTURE CAPITAL NEEDS AND UNCERTAINTY OF ADDITIONAL FUNDING
 
  The Company is working on the research and development of several long-term
projects and is placing increased emphasis on development of the TAH, which
will result in significantly increased internally funded research and
development expenditures. These costs include costs of pre-clinical trials and
regulatory approvals. The Company estimates that the cost of developing the
TAH and other products will be significant. These costs may include costs
related to pre-clinical and clinical trials and regulatory approvals. The
Company estimates that it will require significant additional funds in order
to complete the development and achieve regulatory approvals of the TAH and
other products under development. Generally, estimates of long-term project
costs are extremely imprecise and cost overruns are common. As a result, there
can be no assurance that the Company will not require significantly more
resources to complete the development of the TAH and its other products. The
Company plans to fund this effort through a combination of the TAH Contract,
proceeds from the offering, existing resources, the possible sales of
additional securities and cash flow from sales of its existing products. Even
if the Company does not experience cost overruns, there can be no assurance
that the Company will be able to obtain sufficient funds to complete the
development of the TAH and other products. Moreover, the Company may require
additional funds to commence the manufacture and marketing of the TAH or any
of the Company's other products under development in commercial quantities, if
and when approved or cleared by the regulatory authorities. Failure of the
Company to obtain any required additional funding could delay product
development and otherwise materially and adversely affect the business of the
Company. There can be no assurance that the Company will be able to obtain
additional funding on favorable terms, if at all. See "Use of Proceeds" and
"Management's Discussion and Analysis of Financial Condition and Results of
Operations."
 
DEPENDENCE ON THIRD-PARTY REIMBURSEMENT
 
  The Company's BVS product is, and most of its products under development are
intended to be, sold to medical institutions. Medical institutions and their
physicians typically seek reimbursement for the use of these products from
third-party payors, including Medicare, Medicaid, private health insurers and
managed care organizations. As a result, market acceptance of the Company's
current and proposed products may depend in large part on the extent to which
reimbursement is available to medical institutions and their physicians for
use of the Company's products.
 
  The level of reimbursement provided by United States and foreign third-party
payors varies according to a number of factors, including the medical
procedure category, payor, location, outcome and cost. In the
 
                                      12
<PAGE>
 
United States, many private health care insurance carriers follow the
recommendations of the Health Care Finance Administration ("HCFA"), which
establishes guidelines for the reimbursement of health care providers treating
Medicare and Medicaid patients. Internationally, medical reimbursement systems
vary significantly. In certain countries, medical center budgets are fixed
regardless of levels of patient treatment. In other countries, such as Japan,
reimbursement from government or third party payors must be applied for and
approved. As of the date of this Prospectus, under HCFA guidelines, Medicare
reimburses medical institutions for Medicare patients based on the category of
surgical procedures in which the BVS is used and incrementally reimburses
physicians for the use of the BVS. Medicare does not, however, currently
reimburse medical institutions for the incremental cost of using the BVS above
the amount allowed for the reimbursement category of the surgical procedure.
Certain private health insurers and managed care providers provide incremental
reimbursement to both the medical institutions and their physicians. The
Company is currently petitioning HCFA to assign a higher paying reimbursement
category whenever the BVS is used. In October 1995, HCFA established a special
"ICD-9" code for the BVS in an effort to more clearly track and evaluate
hospital and physician costs associated specifically with the BVS compared to
current reimbursement levels, so that HCFA can determine the appropriate
category and level of reimbursement. There can be no assurance that HCFA will
reassign the BVS to a higher paying category in a timely manner, if at all.
 
  No reimbursement levels have been established for the Company's products
under development, including the TAH. Prior to approving coverage for new
medical devices, most third-party payors require evidence that the product has
received FDA approval or clearance for marketing, is safe and effective and
not
experimental or investigational, and is medically necessary and appropriate
for the specific patient for whom the product is being used. Increasing
numbers of third-party payors require evidence that the procedures in which
the products are used, as well as the products themselves are cost-effective.
There can be no assurance that the Company's products under development will
meet these criteria, that third-party payors will reimburse physicians and
medical institutions for the use of the products or that the level of
reimbursement will be sufficient to support the widespread use of the
products. Furthermore, there can be no assurance that third-party payors will
continue to provide reimbursement for the use of BVS or that such payors will
not reduce the current level of reimbursement for the product. Failure to
achieve adequate reimbursement for its current or proposed products would have
a material adverse effect on the Company's business, financial condition and
results of operations.
 
POTENTIAL INADEQUACY OF PRODUCT LIABILITY INSURANCE
 
  The Company's business involves the risk of product liability claims
inherent in the manufacture and marketing of life support systems. There are
many factors beyond the control of the Company that could result in the
failure of the BVS to sustain the life of a patient, the most important of
which is the condition of the patient prior to the use of the product. As a
result, many of the patients using the BVS do not survive. In addition, the
effectiveness of the Company's products could be adversely affected by the
reliability of the physicians, nurses and technicians using and monitoring the
use of the product, and the maintenance of the product by the Company's
customers. The failure of the BVS or any other life support system under
development by the Company to save a life could give rise to product liability
claims and result in negative publicity that could have a material adverse
effect on the Company's business, financial condition and results of
operations. The Company currently maintains product liability insurance,
subject to certain deductibles and exclusions. There can be no assurance that
this insurance will be sufficient to protect the Company from product
liability claims, or that product liability insurance will continue to be
available to the Company at a reasonable cost, if at all.
 
  The risk of product liability claims against the Company may increase as the
Company introduces new products under development, particularly products such
as the TAH intended for permanent life support. The TAH will have a finite
life and could cause unintended complications to other organs. The eventual
failure of the TAH could give rise to product liability claims, regardless of
whether the TAH has extended or improved the quality of the patient's life
beyond that expected without the use of the TAH. As a result of the additional
 
                                      13
<PAGE>
 
product liability risks that will be associated with the TAH and other
products under development by the Company, there can be no assurance that the
Company will be able to secure product liability insurance for these products,
when and if developed, or that such insurance will be sufficient to protect
the Company at an acceptable cost. The failure of the Company to be able to
obtain adequate product liability insurance, if any, for these products could
have a material adverse effect on its business, financial condition and
results of operations.
 
DEPENDENCE ON PATENTS AND PROPRIETARY RIGHTS
 
  The Company's business depends significantly upon its proprietary
technology. The Company relies on a combination of trade secret laws, patents,
copyrights, trademarks and confidentiality agreements and other contractual
provisions to establish, maintain and protect its proprietary rights, all of
which afford only limited protection. There can be no assurance that others
will not independently develop substantially equivalent proprietary
information and techniques or otherwise gain access to the Company's trade
secrets or disclose such technology or that the Company can meaningfully
protect its trade secrets.
 
  The Company has been issued or allowed 22 patents and has pending three
patent applications in the United States. The Company has obtained or applied
for corresponding patents for certain of these patents and patent applications
in a limited number of foreign countries. These patents relate to the BVS and
certain of its products under development including the TAH. The Company's
United States patents expire at various times from 2003 to 2016. There can be
no assurance that the Company's pending patent applications or any future
applications will be approved, that any patents will provide the Company with
competitive advantages or will not be challenged by third parties, or that the
patents of others will not render the Company's patents obsolete or otherwise
have an adverse effect on the Company's ability to conduct business. Because
foreign patents may afford less protection under foreign law than is available
under United States patent law, there can be no assurance that any such
patents issued to the Company will adequately protect the Company's
proprietary information. Others may have filed and may file patent
applications in the future that are similar or identical to those of the
Company. To determine the priority of inventions, the Company may have to
participate in interference proceedings declared by the United States Patent
and Trademark Office or opposition proceedings before a foreign patent office
that could result in substantial cost to the Company. No assurance can be
given that any such interfering patent or patent application will not have
priority over patent applications filed on behalf of the Company or that the
Company will prevail in any opposition proceeding.
   
  The medical device industry is characterized by a large number of patents
and by frequent and substantial intellectual property litigation. There can be
no assurance that the Company's products and technologies do not infringe any
patents or proprietary rights of third parties. The Company has in the past
and may in the future be notified that it may be infringing intellectual
property rights possessed by others. Any intellectual property litigation
would be costly and could divert the efforts and attention of the Company's
management and technical personnel, which could have a material adverse effect
on the Company's business, financial condition and results of operations.
There can be no assurance that infringement claims will not be asserted in the
future or such assertions, if proven to be true, will not prevent the Company
from selling its products or materially and adversely affect the Company's
business, financial condition and results of operations. If any such claims
are asserted against the Company's intellectual property rights, it may seek
to enter into a royalty or licensing arrangement. There can be no assurance,
however, that a license will be available on reasonable terms, or at all. The
Company could decide, in the alternative, to resort to litigation to challenge
such claims or to design around the patented technology. Such actions could be
costly and would divert the efforts and attention of the Company's management
and technical personnel, which would materially and adversely affect the
Company's business, financial condition and results of operations.     
   
  The Company has recently received a letter from a third party alleging that
certain technology incorporated into the transcutaneous energy transmission
system component of the Company's TAH may infringe the patent or other
intellectual property rights of that party. The Company is in the preliminary
stages of assessing the allegations, but does not believe that it is
infringing any patent or other intellectual     
 
                                      14
<PAGE>
 
   
property rights of this third party. There can be no assurance that the
Company would prevail in the defense of an infringement claim, if made. If
infringement of the proprietary rights of the third party were determined to
exist, the Company would either be required to use or develop alternative
technology or to seek a license of the technology. There can be no assurance
that the Company could obtain a license of this technology on a timely basis
or on reasonable terms, if at all. In addition, there can be no assurance that
the Company could develop or license alternative technology on a timely basis,
if at all. As a result, a determination of infringement could have a material
adverse affect on the Company's development of the TAH and on its business,
financial condition and results of operations. Any patent or intellectual
property dispute or litigation could result in product development delays,
would be costly, could divert the efforts and attention of the Company's
management and technical personnel and could have a material adverse effect on
the Company's business, financial condition and results of operations. See
"Business--Patents and Proprietary Rights."     
 
CONTROL BY MANAGEMENT
 
  Upon completion of this offering, the Company's directors, officers and
their affiliates will beneficially own approximately 27.2% of the outstanding
Common Stock of the Company (as determined in accordance with the rules of the
Securities and Exchange Commission). As a result, these stockholders will be
able to exert substantial influence over actions requiring stockholder
approval, including the election of directors, amendments to the Company's
Restated Certificate of Incorporation, mergers, sales of assets or other
business acquisitions or dispositions. See "Principal and Selling
Stockholders."
 
ANTI-TAKEOVER PROVISIONS; RIGHTS AGREEMENT; ISSUANCE OF PREFERRED STOCK
 
  The Company's Restated Certificate of Incorporation ("Certificate of
Incorporation") and Amended and Restated By-laws ("By-laws") contain certain
provisions that could have the effect of deterring certain mergers, tender
offers, proxy contests or other future takeover attempts which holders of some
or even a majority of the outstanding stock believe to be in their best
interest, and may make removal of management more difficult even if such
removal would be deemed to be beneficial to stockholders generally. These
provisions could limit the price that certain investors might be willing to
pay in the future for shares of the Company's Common Stock. In addition, the
Company has adopted a Rights Agreement, pursuant to which the Company has
distributed to its stockholders rights to purchase shares of junior
participating preferred stock ("Rights Agreement"). Upon certain triggering
events, such rights become exercisable to purchase the Company's Common Stock
at a price substantially discounted from the then applicable market price of
the Company's Common Stock. The Rights Agreement could generally discourage a
merger or tender offer involving the securities of the Company that is not
approved by the Company's Board of Directors by increasing the cost of
effecting any such transaction and, accordingly, could have an adverse impact
on stockholders who might want to vote in favor of such merger or participate
in such tender offer. In addition, shares of the Company's Class B Preferred
Stock ("Preferred Stock") may be issued in the future without further
stockholder approval and upon such terms and conditions, and having such
rights, privileges and preferences, as the Board of Directors may determine.
The rights of the holders of Common Stock will be subject to, and may be
adversely affected by, the rights of any holders of Preferred Stock that may
be issued in the future. The issuance of Preferred Stock, while providing
desirable flexibility in connection with possible acquisitions and other
corporate purposes, could have the effect of making it more difficult for a
third party to acquire, or of discouraging a third party from acquiring, a
majority of the outstanding voting stock of the Company. The Company has no
present plans to issue any shares of Preferred Stock. The Certificate of
Incorporation and By-laws impose various procedural and other requirements
that could make it more difficult for stockholders to effect certain corporate
actions. See "Description of Capital Stock--Anti-takeover Effect of Provisions
of the Certificate of Incorporation and By-laws, Rights Distribution and
Delaware Law."
 
POSSIBLE VOLATILITY OF SHARE PRICE
 
  There has been a history of significant volatility in the market price for
shares of the Common Stock and shares of other companies in the medical
products and biomedical technology fields. Factors such as the announcement of
new products and the achievement of developmental and regulatory milestones by
the
 
                                      15
<PAGE>
 
Company or its competitors have caused and could cause the price of the Common
Stock to fluctuate significantly. Moreover, although there has been a public
trading market for the Common Stock since 1987, there have been periods of
limited trading activity resulting in further volatility of the stock price.
Additionally, the spread between the ask and bid prices for the Common Stock on
the Nasdaq National Market System has been relatively wide, potentially
discouraging investor trades in the Common Stock. Further, in the event that in
some future fiscal quarter the Company's revenues were below the expectations
of public market analysts and investors, the price of the Common Stock could be
materially adversely affected. In addition, stock markets have experienced
extreme price and volume trading volatility in recent years. This volatility
has had a substantial effect on market prices of securities of many medical
technology companies for reasons frequently unrelated or disproportionate to
the operating performance of the specific companies. These broad market
fluctuations may adversely affect the market price of the Common Stock. See
"Price Range of Common Stock."
 
SHARES ELIGIBLE FOR FUTURE SALE
   
  Sales of a substantial number of shares of Common Stock in the public market
following this offering (pursuant to Rule 144 or otherwise), as well as sales
of shares issued upon exercise of employee stock options, could adversely
affect the prevailing market price of the Common Stock and impair the Company's
ability to raise additional capital through the sale of equity securities. Of
the approximately 8,264,556 shares of Common Stock outstanding at September 30,
1997, approximately 5,391,682 shares are eligible for resale in the public
market without restriction and approximately 1,474,318 shares are eligible for
resale subject to the provisions of Rule 144. The remaining 1,398,556 shares of
Common Stock are "restricted securities" within the meaning of Rule 144, of
which 2,000 shares and 1,396,556 shares will not be eligible for resale until
January and July 1998, respectively, the expiration of the one-year holding
period under Rule 144, and then only in accordance therewith. In addition,
there are 964,410 shares subject to outstanding options, which shares have been
registered on Form S-8 and will therefore be subject to resale in the public
market either without restriction or subject to the provisions of Rule 144. The
holders of 1,396,556 shares of Common Stock have certain registration rights,
commencing on July 14, 1998. The Company's executive officers, directors,
Genzyme Corporation ("Genzyme") and each of the Selling Stockholders who, in
the aggregate hold approximately 2,872,874 shares of Common Stock (2,722,874
shares of Common Stock after the sale of shares of Common Stock by the Selling
Stockholders in the offering) have agreed that, for a period of 90 days from
the date of this Prospectus, subject to certain limited exceptions, they will
not, directly or indirectly, without the prior written consent of BancAmerica
Robertson Stephens, sell, offer, contract to sell, pledge, grant any option to
purchase or otherwise dispose of any shares of Common Stock or any securities
convertible into or exchangeable for, or any rights to purchase or acquire,
Common Stock held by them, thereafter acquired by them or which may be deemed
to be beneficially owned by them. See "Certain Transactions" and
"Underwriting."     
 
                                       16
<PAGE>
 
                                USE OF PROCEEDS
   
  The net proceeds to the Company from the sale of the 2,250,000 shares of
Common Stock offered by the Company hereby are estimated to be $46.7 million
($54.2 million if the Underwriters' over-allotment option is exercised in
full), assuming an offering price of $22.125 per share and after deducting
estimated underwriting discounts and commissions and offering expenses payable
by the Company. The Company will not receive any proceeds from the sale of
shares of Common Stock by the Selling Stockholders.     
 
  The Company expects to use the net proceeds from this offering for research
and development, expansion of its manufacturing capabilities and other general
corporate purposes. In particular, the Company expects that a substantial
portion of the net proceeds will be used to support the TAH and other
development efforts, although there can be no assurance that the net proceeds
will be so used. The Company may also use a portion of the net proceeds for
strategic acquisitions of businesses, products or technologies complementary
to the Company's business. The Company does not have any commitments to make
any such acquisitions and has not allocated a specific amount of the net
proceeds for this purpose. Pending such uses, the Company plans to invest the
net proceeds of the offering in short-term, interest-bearing investment-grade
securities.
 
                                DIVIDEND POLICY
 
  The Company has never declared or paid cash dividends on its capital stock
and does not plan to pay any cash dividends in the foreseeable future. The
Company's current policy is to retain all of its earnings to finance future
growth.
 
                                      17
<PAGE>
 
                          PRICE RANGE OF COMMON STOCK
 
  The Company's Common Stock is traded on the Nasdaq National Market under the
symbol "ABMD." The following table sets forth, for the periods indicated, the
high and low sales prices per share of Common Stock, as reported by the Nasdaq
National Market.
 
<TABLE>   
<CAPTION>
                                                                  HIGH     LOW
                                                                 ------- -------
<S>                                                              <C>     <C>
FISCAL YEAR ENDED MARCH 31, 1996
First Quarter................................................... $ 9     $ 6
Second Quarter..................................................  13 1/4   6 7/8
Third Quarter...................................................  16       8 3/4
Fourth Quarter..................................................  15 1/4  11 1/2
FISCAL YEAR ENDED MARCH 31, 1997
First Quarter...................................................  18      12 1/2
Second Quarter..................................................  18 1/4  10 1/8
Third Quarter...................................................  18 1/4  11 1/2
Fourth Quarter..................................................  13 1/4   9 1/2
FISCAL YEAR ENDING MARCH 31, 1998
First Quarter...................................................  16       9 1/2
Second Quarter..................................................  19      13 1/2
Third Quarter (through October 9, 1997).........................  23 1/8  16 3/4
</TABLE>    
   
  The last reported sale price of the Common Stock on the Nasdaq National
Market on October 9, 1997 was $22.125 per share. As of September 30, 1997,
there were approximately 337 holders of record of the Company's Common Stock,
including multiple beneficial holders at depositories, banks and brokers
listed as a single holder in the street name of each respective depository,
bank or broker.     
 
                                      18
<PAGE>
 
                                CAPITALIZATION
   
  The following table sets forth as of September 30, 1997 the unaudited actual
capitalization of the Company, and such capitalization as adjusted to reflect
the receipt of the estimated net proceeds from the sale of 2,250,000 shares of
Common Stock being offered by the Company hereby at an assumed offering price
of $22.125 per share and after deducting estimated underwriting discounts and
commissions and offering expenses payable by the Company.     
 
<TABLE>   
<CAPTION>
                                                         SEPTEMBER 30, 1997
                                                      ------------------------
                                                         ACTUAL    AS ADJUSTED
                                                      ------------ -----------
                                                           (in thousands)
<S>                                                   <C>          <C>
Long-term debt....................................... $       --   $      --
                                                      ------------ -----------
Stockholders' investment (1):
  Class B Preferred Stock, $0.01 par value, 1,000,000
   shares authorized; no shares issued and
   outstanding; .....................................          --          --
  Common Stock, $.01 par value, 25,000,000 shares
   authorized; 8,264,556 shares issued and
   outstanding and 10,514,556 shares issued and
   outstanding as adjusted...........................       82,646     105,146
  Additional paid-in capital.........................   53,221,747  99,867,419
  Accumulated deficit................................ (20,655,947) (20,655,947)
                                                      ------------ -----------
    Total stockholders' investment...................   32,648,446  79,316,618
                                                      ------------ -----------
      Total capitalization........................... $ 32,648,446 $79,316,618
                                                      ============ ===========
</TABLE>    
- --------
   
(1) Based on the number of shares outstanding as of September 30, 1997.
    Excludes 964,410 shares of Common Stock reserved for issuance upon the
    exercise of stock options outstanding as of September 30, 1997 at a
    weighted average exercise price of $10.81 per share. See Note 6 to
    Consolidated Financial Statements.     
 
                                      19
<PAGE>
 
                     SELECTED CONSOLIDATED FINANCIAL DATA
   
  The following table contains certain selected consolidated financial data of
the Company and is qualified in its entirety by the more detailed Consolidated
Financial Statements included elsewhere in this Prospectus. The consolidated
statements of operations data for the fiscal years ended March 31, 1995, 1996
and 1997, and the consolidated balance sheet data as of March 31, 1996 and
1997, have been derived from the Consolidated Financial Statements, which
statements have been audited by Arthur Andersen LLP, independent public
accountants, and are included elsewhere in this Prospectus. The consolidated
statement of operations data for the fiscal years ended March 31, 1993 and
1994, and the consolidated balance sheet data as of March 31, 1993, 1994 and
1995 have been derived from the Company's consolidated financial statements,
which statements have been audited by Arthur Andersen LLP and are not included
in this Prospectus. The consolidated statement of operations data for the six
months ended September 30, 1996 and 1997, and the consolidated balance sheet
data as of September 30, 1997 have been derived from unaudited Consolidated
Financial Statements included elsewhere in this Prospectus. These unaudited
financial statements have been prepared on the same basis as the audited
financial statements and, in the opinion of management, include all
adjustments and reclassifications (consisting only of normal recurring
adjustments and reclassifications) necessary to present fairly the financial
condition and results of operations for the periods presented. The results for
the six months ended September 30, 1997 are not necessarily indicative of the
results that may be expected for the full year. This data should be read in
conjunction with the Consolidated Financial Statements and "Management's
Discussion and Analysis of Financial Condition and Results of Operations"
appearing elsewhere herein.     
 
<TABLE>   
<CAPTION>
                                                                      SIX MONTHS
                                                                         ENDED
                                  YEAR ENDED MARCH 31,               SEPTEMBER 30,
                         ------------------------------------------- -------------
                          1993     1994     1995     1996     1997    1996   1997
                         -------  -------  -------  -------  ------- ------ ------
                                 (in thousands, except per share data)
<S>                      <C>      <C>      <C>      <C>      <C>     <C>    <C>
STATEMENT OF OPERATIONS
 DATA:
Revenues:
  Products.............. $ 1,709  $ 4,648  $ 6,893  $ 9,725  $12,311 $5,760 $9,324
  Contracts.............   1,736    2,027    2,337    3,118    4,151  1,754  3,680
                         -------  -------  -------  -------  ------- ------ ------
    Total revenues......   3,445    6,675    9,230   12,843   16,462  7,514 13,004
Costs and expenses:
  Cost of products......   2,042    2,211    3,289    3,921    5,361  2,123  3,438
  Research and
   development (1)......   2,097    2,431    2,464    3,218    3,833  1,781  3,654
  Selling, general and
   administrative.......   3,803    4,553    4,278    5,741    7,068  3,229  4,970
                         -------  -------  -------  -------  ------- ------ ------
    Total costs and
     expenses...........   7,942    9,195   10,031   12,880   16,262  7,133 12,062
                         -------  -------  -------  -------  ------- ------ ------
Income (loss) from
 operations.............  (4,497)  (2,520)    (801)     (37)     200    381    942
Interest and other
 income.................     604      537      449      528      535    256    417
                         -------  -------  -------  -------  ------- ------ ------
Net income (loss)....... $(3,893) $(1,983) $  (352) $   491  $   735 $  637 $1,359
                         =======  =======  =======  =======  ======= ====== ======
Net income (loss) per
 common and common
 equivalent share....... $ (0.60) $ (0.31) $ (0.05) $  0.07  $  0.10 $ 0.09 $ 0.17
                         =======  =======  =======  =======  ======= ====== ======
Weighted average number
 of common and common
 equivalent shares
 outstanding............   6,441    6,461    6,512    6,995    7,162  7,196  7,869
</TABLE>    
 
<TABLE>   
<CAPTION>
                                        MARCH 31,
                         --------------------------------------- SEPTEMBER 30,
                          1993    1994    1995    1996    1997       1997
                         ------- ------- ------- ------- ------- -------------
                                            (in thousands)
<S>                      <C>     <C>     <C>     <C>     <C>     <C>
BALANCE SHEET DATA:
Cash, cash equivalents
 and short-term
 marketable securities.. $ 9,486 $ 3,067 $ 4,491 $10,647 $ 9,361    $24,312
Working capital.........  10,727   6,043   6,304  12,735  12,850     29,109
Long-term investments...   4,307   7,219   6,533     --      --         --
Total assets............  17,504  15,426  14,730  16,209  18,547     36,348
Long-term debt..........   3,820   3,773     --      --      --         --
Total stockholders'
 investment (2).........  12,460  10,589  13,305  13,945  15,225     32,648
</TABLE>    
- -------
(1) Research and development expenses include certain contract costs. See Note
    1(e) to Consolidated Financial Statements.
          
(2) No cash dividends on Common Stock were declared or paid during any of the
    periods presented.     
 
                                      20
<PAGE>
 
   MANAGEMENT'S DISCUSSION AND ANALYSIS OFFINANCIAL CONDITION AND RESULTS OF
                                   OPERATIONS
 
  The following Management's Discussion and Analysis of Financial Condition and
Results of Operations contains forward-looking statements which involve risks
and uncertainties. The Company's actual results could differ materially from
those anticipated in these forward-looking statements as a result of certain
factors, including those set forth under "Risk Factors" and elsewhere in this
Prospectus.
 
OVERVIEW
 
  The Company is a leader in the research and development of cardiac assist and
heart replacement technology. The Company developed, manufactures and sells the
BVS, a temporary cardiac assist device, and is developing a totally implantable
artificial heart. The Company's operating results reflect the dual activities
of commercial operations and investments in the research and development of new
technologies.
   
  The BVS is a temporary cardiac assist device designed to provide a patient's
failing heart with full circulatory assistance while allowing the heart to
rest, heal and recover its function. The BVS is the only device that can
provide full circulatory assistance approved by the FDA as a bridge-to-recovery
device for the treatment of patients with reversible heart failure. Since
fiscal 1994, the first full year of marketing the BVS in the United States,
increasing new orders and reorders of the BVS have made product revenues the
largest contributor to the Company's revenues. The Company has focused its
initial selling efforts of the BVS on the approximately 300 medical centers
that perform the most heart surgery procedures, teaching centers and transplant
centers. As of September 30, 1997, the BVS had been purchased by over 275
medical centers in the United States, many of which are within the group of
medical centers initially targeted. The BVS is comprised of a pneumatic drive
and control console, single-use external blood pumps and cannulae. During the
six months ended September 30, 1997 and fiscal 1997, revenues from BVS sales
represented greater than 90% of the Company's total product revenues with no
single customer representing more than 5% of product revenues.     
 
  Research and development is a significant portion of the Company's
operations. The Company's research and development efforts are focused on the
development of new products, primarily related to cardiac assist and heart
replacement, and the continued enhancement of the BVS and related technologies.
The Company's research and development expenses have been primarily
attributable to research and development under the Company's government
contracts and grants. Revenues from contract research and development and total
research and development costs have increased in each of the past three years.
The Company's government-sponsored research and development contracts generally
provide for payment on a cost-plus-fixed-fee basis. The Company accounts for
revenue under these contracts and grants as work is performed, provided that
the government has appropriated sufficient funds for the work. There can be no
assurance that the government will not terminate, reduce or delay the funding
for any of the Company's contracts. In addition, there can be no assurance that
the Company will be successful in obtaining any new government contracts or
further extensions to existing contracts.
   
  The Company plans to use its own resources to fund the further development of
the TAH in amounts significantly in excess of the funding provided under the
Company's TAH Contract. The Company estimates that the development of the TAH,
including conducting pre-clinical and clinical studies and obtaining regulatory
approvals, will require substantial funds. As a result, the Company believes
that it is likely that the Company will incur losses, potentially as soon as
the quarter ending December 31, 1997. There can be no assurance that the
Company will be able to develop the TAH, or receive the required regulatory
approvals to commence clinical trials on a timely basis or within budget, if at
all.     
 
  The Company has significant net tax operating loss carryforwards and tax
credit carryforwards. As a result, income tax expense incurred during the
periods presented have not been material. See Note 4 to Consolidated Financial
Statements.
 
 
                                       21
<PAGE>
 
RESULTS OF OPERATIONS
 
  The following table sets forth certain consolidated statements of operations
data for the periods indicated as a percentage of total revenues:
 
<TABLE>   
<CAPTION>
                                                       SIX MONTHS
                                                          ENDED
                             YEAR ENDED MARCH 31,     SEPTEMBER 30,
                             -----------------------  --------------
                              1995     1996    1997    1996    1997
                             ------   ------  ------  ------  ------
<S>                          <C>      <C>     <C>     <C>     <C>
Revenues:
  Products..................   74.7%    75.7%   74.8%   76.7%   71.7%
  Contracts.................   25.3     24.3    25.2    23.3    28.3
                             ------   ------  ------  ------  ------
    Total revenues..........  100.0    100.0   100.0   100.0   100.0
Costs and expenses:
  Cost of products..........   35.6     30.5    32.6    28.2    26.5
  Research and development..   26.7     25.1    23.3    23.7    28.1
  Selling, general and
   administrative...........   46.4     44.7    42.9    43.0    38.2
                             ------   ------  ------  ------  ------
    Total costs and
     expenses...............  108.7    100.3    98.8    94.9    92.8
                             ------   ------  ------  ------  ------
Income (loss) from
 operations.................   (8.7)    (0.3)    1.2     5.1     7.2
Interest and other income...    4.9      4.1     3.2     3.4     3.2
                             ------   ------  ------  ------  ------
Net income (loss)...........   (3.8)%    3.8%    4.4%    8.5%   10.4%
                             ======   ======  ======  ======  ======
</TABLE>    
   
 Six Months Ended September 30, 1997 and 1996     
          
  Revenues. Total revenues, excluding interest income, increased by 73% to
$13.0 million in the six months ended September 30, 1997 from $7.5 million in
the six months ended September 30, 1996. This increase was attributable to an
increase in both product and contract revenues.     
   
  Product revenues increased by 62% to $9.3 million in the six months ended
September 30, 1997 from $5.8 million in the six months ended September 30,
1996. This increase was primarily attributable to increased unit sales of BVS
blood pumps, consoles and related accessories. Product revenues during the six
months ended September 30, 1997 included a $640,000 reduction in the Company's
backlog for BVS blood pumps. This backlog had primarily resulted from the
Company's voluntary recall of certain production lots of single-use BVS blood
pumps during the quarter ended December 31, 1996. As of September 30, 1997,
the Company's backlog of unshipped customer orders was $370,000. More than 90%
of total product revenues in the six months ended September 30, 1997 were
derived from domestic sources.     
   
  Contract revenues increased by 110% to $3.7 million in the six months ended
September 30, 1997 from $1.8 million in the six months ended September 30,
1996. This increase primarily reflected increased activity under the Company's
TAH Contract. The Company accounts for revenue under its government contracts
and grants as work is performed, provided that the government has appropriated
sufficient funds for the work. Through September 30, 1997, the government had
appropriated $4.9 million of the $8.5 million Phase II TAH Contract amount.
The original government appropriation schedule calls for no further
appropriation for the TAH Contract until October 1998. This schedule is
subject to change at the discretion of the government. During the six months
ended September 30, 1997, the Company's expenditures under the TAH Contract
exceeded the appropriated amount, resulting in the Company recognizing as
revenue all of the remaining $3.2 million balance of the $4.9 million
appropriated under the TAH Contract.     
   
  While the Company currently plans to further increase its expenditures in
connection with the development of the TAH, the Company will not recognize any
further contract revenues under the TAH Contract until such time as additional
funds are appropriated under the TAH Contract, if ever. The Company believes
that certain of its costs incurred prior to further appropriations may be
reimbursable under the TAH     
 
                                      22
<PAGE>
 
   
Contract, if and when additional appropriation under the TAH Contract is made.
Due to the Company's accelerated TAH development activity and the timing of
government appropriations, the Company believes that it will experience
significant quarterly fluctuations in contract revenues. The Company also
believes that its total expenses to complete the development of the TAH will
significantly exceed the remaining $3.6 million TAH Contract amount. As a
result, the Company believes that it is likely that the Company will again
incur losses, potentially as soon as the quarter ending December 31, 1997.
       
  As of September 30, 1997, the Company's total backlog of research and
development contracts and grants was $8.7 million, including the remaining
$3.6 million under the TAH Contract and $3.0 million for Heart Booster
research and development. Funding for the Company's government research and
development contracts is subject to government appropriation, and all of these
contracts contain provisions which make them terminable at the convenience of
the government.     
   
  Cost of Products. Cost of products sold as a percentage of product revenues
remained unchanged at 36.9% for the six months ended September 30, 1997 and
1996.     
   
  Research and Development Expenses. Research and development expenses
increased by 105% to $3.7 million, 28% of total revenues, for the six months
ended September 30, 1997, from $1.8 million, 24% of total revenues, for the
six months ended September 30, 1996. This increase primarily reflected a
higher level of activity under the Company's cost-plus-fixed-fee research and
development contracts and grants, particularly the TAH Contract. Research and
development expenses during the six months ended September 30, 1997 also
included $230,000 of expenses incurred in connection with the Company's
development activities for the TAH in excess of the appropriated amounts under
the TAH Contract. The Company anticipates that its research and development
expenses will increase significantly as a result of its plans to increase its
internally funded research and development efforts for TAH.     
   
  Selling, General and Administrative Expenses. Selling, general and
administrative expenses increased by 54% to $5.0 million, 38% of total
revenues, for the six months ended September 30, 1997 from $3.2 million, 43%
of total revenues, for the six months ended September 30, 1996. The increase
in absolute dollars primarily reflected increased sales and marketing
expenses, particularly increased personnel and sales commissions, related to
the increase in product revenues, as well as additional administrative
personnel. The decrease in selling, general and administrative expenses as a
percentage of total revenues reflected the Company's higher revenue base to
support these increased costs.     
   
  Interest and Other Income. Interest and other income consists primarily of
interest on the Company's investment balances, net of interest and other
expenses. Interest income increased by 62% to $417,000, 3% of total revenues,
for the six months ended September 30, 1997, from $257,000, 3% of total
revenues, for the six months ended September 30, 1996. This increase primarily
reflected the interest earned on the Company's higher average investment
balances.     
       
       
 Fiscal Years Ended March 31, 1997, 1996 and 1995
 
  Revenues. Total revenues, excluding interest income, for fiscal 1997
increased to $16.5 million as compared to $12.8 million in fiscal 1996 and
$9.2 million in fiscal 1995, representing increases of 28% and 39% in fiscal
1997 and 1996, respectively.
 
  Product revenues increased to $12.3 million in fiscal 1997 from $9.7 million
in fiscal 1996, and $6.9 million in fiscal 1995, representing increases of 27%
and 41% in fiscal 1997 and fiscal 1996, respectively. These increases were
primarily attributable to growing United States unit sales of the BVS consoles
and single-use products, including increased blood pump reorders, and to
increased average selling prices of BVS consoles and single-use products. The
majority of the Company's product revenues in the last three years have been
to United States customers. International revenues represented 7%, 9% and 13%
of total product revenues in fiscal 1997, 1996 and 1995 respectively. The
Company's product revenues from its dental business, ABIODENT, increased in
fiscal 1997 but were less than 10% of total product revenues.
 
                                      23
<PAGE>
 
  Contract revenues increased to $4.2 million in fiscal 1997 from $3.1 million
in fiscal 1996 and $2.3 million in fiscal 1995, representing increases of 33%
in both fiscal 1997 and 1996. These increases are reflective of the increased
level of the Company's research and development activities under its
government cost reimbursement contracts in each year. The majority of the
Company's contract revenues, approximately 59% in fiscal 1997, were recognized
in connection with the research and development under the TAH Contract,
including amounts paid under Phase I of that contract.
   
  Cost of Products. Cost of products represented approximately 44%, 40% and
48% of product revenues for fiscal 1997, 1996 and 1995, respectively. The
decrease in gross product margins experienced in fiscal 1997 as compared to
fiscal 1996 is primarily attributable to the mix of products sold. The Company
generally receives higher margins on the sale of single-use blood pumps than
on the sale of consoles. A higher proportion of the Company's revenues was
derived from the sale of BVS consoles in fiscal 1997 as compared to fiscal
1996. In addition, the Company's margins in fiscal 1997 were affected by
increased costs of production of the single-use blood pumps, including
approximately $200,000 in costs related to the Company's voluntary recall
during the third quarter of fiscal 1997 of certain production lots of single-
use BVS blood pumps. During that quarter, the Company became aware of certain
isolated cases where components of its BVS blood pumps exhibited certain
abnormalities. In response the Company commenced a product recall for and
removed from inventory all blood pumps from the affected production lots.     
       
  Research and Development Expenses. Cost of research and development
increased to approximately $3.8 million, 23.3% of total revenues, in fiscal
1997 compared to $3.2 million, 25.1% of total revenues, and $2.5 million,
26.7% of total revenues, in fiscal 1996 and 1995, respectively. These
increases reflect increased activity under research and development contracts
and grants, which are billed on a cost-plus-fixed-fee basis. Costs of internal
research and development primarily relate to continued engineering support and
improvement of existing products as well as regulatory support for all
products.
 
  Selling, General and Administrative Expenses. Selling, general and
administrative expenses increased to $7.1 million, 42.9% of total revenues, in
fiscal 1997 from $5.7 million, 44.7% of total revenues, and $4.3 million,
46.4% of total revenues, in fiscal 1996 and fiscal 1995, respectively. These
increases primarily reflect increased costs associated with higher product
revenues, including the expansion of the United States based sales team and
clinical post-sales support personnel. The decreases in selling, general and
administrative expenses as a percentage of total revenues in fiscal 1996 and
1997 primarily reflect the Company's higher revenue base to support these
increased costs.
 
  Interest and Other Income. Interest and other income totaled $540,000,
$530,000, and $450,000, for fiscal 1997, 1996 and 1995, respectively. This
income primarily represents income earned on short-term investments.
 
LIQUIDITY AND CAPITAL RESOURCES
   
  As of September 30, 1997, the Company had $24.3 million in cash and short-
term marketable securities. The Company also has a $3.0 million line of credit
from a bank that expires in September 1998, and which was entirely available
at September 30, 1997.     
   
  During the six months ended September 30, 1997, operating activities
provided $2,000 of cash. Net cash provided by operating activities during the
six months ended September 30, 1997 reflected net income of $1.4 million,
including depreciation and amortization expense of $440,000, and an increase
in accrued expenses of $535,000. These sources of cash were partially offset
by an increase in accounts receivable of $2.0 million, a decrease in accounts
payable of $156,000, and increases in prepaid expenses and inventory of
$220,000 and $30,000, respectively. The increase in the Company's accounts
receivable was primarily attributable to the Company's increased sales,
including an increase in product revenues attributable to sales-type lease
transactions.     
 
                                      24
<PAGE>
 
   
  During the six months ended September 30, 1997, investing activities used
$17.0 million of cash. Net cash used by investing activities included $15.9
million of purchases of short-term investments and $1.1 million of purchases
and improvements of property and equipment. Although the Company does not
currently have significant capital commitments, the Company believes that it
will continue to make significant investments over the next several years to
support the development and commercialization of its products and the expansion
of its manufacturing facility.     
   
  During the six months ended September 30, 1997, financing activities provided
$16.1 million of cash. Net cash provided by financing activities included $16.0
million in net proceeds from the private placement of Common Stock to Genzyme
Corporation and certain of the Company's directors in July 1997.     
       
  The Company believes that its revenues and existing resources, together with
the proceeds from the offering, will be sufficient to fund its planned
operations, including the planned increase in its internally funded TAH
development efforts, for at least through the next twelve months.
 
                                       25
<PAGE>
 
                                   BUSINESS
 
  The Company is a leader in the research and development of cardiac assist
and heart replacement technology. The Company developed, manufactures and
sells the BVS, a temporary cardiac assist device designed to provide a
patient's failing heart with full circulatory assistance while allowing the
heart to rest, heal and recover its function. The BVS is most frequently used
in patients whose hearts fail to immediately recover function following heart
surgery. The BVS is the only device that can provide full circulatory
assistance approved by the FDA as a bridge-to-recovery device for the
treatment of patients with reversible heart failure.
 
  The Company is developing a battery-powered totally implantable artificial
heart intended as a permanent replacement device to assume the full pumping
function of both the left and right ventricles of the heart. The TAH is
designed for use by patients with irreparably damaged hearts and at risk of
death due to acute myocardial infarction ("AMI"), chronic ischemic disease or
some form of end-stage congestive heart failure, but whose vital organs
otherwise remain viable.
 
HEART DISEASE
 
 Overview
 
  The human heart consists of four chambers, including a left and right
ventricle. The left ventricle pumps oxygen rich blood throughout the body. The
right ventricle pumps oxygen depleted blood which has been circulated through
the body to the lungs where it is re-oxygenated. The heart muscles of the
ventricles require an uninterrupted supply of oxygenated blood, which is
provided through coronary arteries.
 
  Insufficient blood flow to the muscles of the heart, known as ischemia,
results in oxygen deprivation and leads to various complications. These
complications include reduced cell function and, in more severe cases,
permanent damage to the heart muscle, such as AMI. Diseases to the coronary
arteries which affect blood flow to the heart are generally classified as
coronary heart disease.
 
  Congestive heart failure is a condition manifested clinically by an enlarged
heart. Congestive heart failure develops over time primarily due to excess
demand on the heart muscle caused by a variety of factors, including chronic
hypertension (high blood pressure), incompetent valves, coronary heart
disease, infections of the heart muscle or the valves and congenital heart
problems.
 
  Abnormalities in the electrical conduction system regulating the pumping
function of the heart, known as rhythm disorders, can also lead to
complications. These complications range from ventricular fibrillation
(unsynchronized contractions) and arrhythmia (irregular heartbeats) to cardiac
arrest. Most cardiac arrests result in sudden death.
 
 Prevalence and Mortality
 
  In 1994, there were an estimated 13.7 million people with coronary heart
disease, 4.8 million people with congestive heart failure, 4.0 million people
with rhythm disorders, and 1.4 million people with valvular diseases in the
United States. These diseases and conditions resulted in approximately 750,000
deaths in 1995, of which approximately half were sudden deaths. Of the deaths
that did not occur suddenly, approximately 110,000, 131,000, and 59,000 were
associated with AMI, chronic ischemic disease and congestive heart failure,
respectively.
 
 Circulatory Support Therapies
 
  In general, there are four modalities for the treatment or support of
failing ventricles: pharmaceutical therapies, cardiological interventions,
surgical corrections, and mechanical cardiac interventions. Pharmaceutical
therapies, including diuretics, ACE inhibitors, beta blockers and calcium
channel blockers, are commonly the first treatment option. Cardiological
interventions, including angioplasty and the use of stents, are minimally
invasive procedures that primarily address certain forms of coronary heart
disease. Surgical corrections, including coronary bypass surgery and valve
replacement, while effective, are a viable alternative only for those patients
with enough functional heart muscle to sustain life. Mechanical cardiac
 
                                      26

<PAGE>
 
interventions involve the use of devices for those patients whose heart
muscles are unable to sustain life without cardiac assistance.
 
 Mechanical Cardiac Interventions
 
  Mechanical cardiac interventions can be divided into three groups of
devices: temporary cardiac assist, permanent cardiac assist and heart
replacement.
 
  Temporary Cardiac Assist. Patients who are candidates for temporary cardiac
assist consist of those with severely but reversibly failing hearts and those
who need ventricular support to remain alive while they await transplantation.
Temporary cardiac devices which are designed to support the recovery of
patients with reversibly failing hearts are referred to as "bridge-to-
recovery" devices, and those which can support patients awaiting
transplantation are referred to as "bridge-to-transplant" devices.
Approximately 12,000 patients with potentially recoverable hearts die every
year in the United States following heart surgery. Bridge-to-recovery devices
can save the lives of many of these patients by temporarily assuming the
pumping function of the heart, while allowing the heart to rest, heal and
recover its normal function. These devices can also be used for bridge-to-
recovery for nonsurgical patients who would otherwise die as a result of
certain transient viral infections that attack the heart muscle. Bridge-to-
transplant devices are ventricular assist devices ("VADs") used to support a
portion of the patients awaiting heart transplants. There are approximately
2,300 heart transplants performed in the United States annually.
 
  Permanent Cardiac Assist. Patients with life-impairing or life-threatening
heart failure due to permanent muscle damage may require support to either the
left or both ventricles. Depending upon the severity of the damage and the
nature of the heart's condition, these patients may be helped with permanent
assist devices. Permanent assist devices under development can be grouped into
two types, those that pump blood directly, such as VADs, and those that wrap
around and help contract the heart without direct blood contact. Both types
potentially may be used to treat end-stage congestive heart failure patients
as well as those patients who are not at imminent risk of death but whose
daily activities are generally restricted due to their weakened hearts. In
1995, there were approximately 59,000 deaths in the United States attributable
to congestive heart failure.
 
  Heart Replacement. Patients with irreparably damaged hearts and at risk of
death due to AMI, chronic ischemic disease or some form of end-stage
congestive heart failure but whose vital organs otherwise remain viable are
candidates for heart replacement. Included among these patients are those with
massive heart damage or infection, severe rhythm disorders, prosthetic valves,
clots or thrombi in the ventricles, high pulmonary resistance, chronic right
ventricle failure and heart transplant rejection. Among these combined groups,
the Company believes that approximately 60,000 patients per year could benefit
from a heart replacement device. No life-supporting treatment is currently
available for these patients except for the approximately 2,300 who receive
heart transplants annually in the United States. Currently, available donor
hearts are primarily reserved for transplantation of select end-stage
congestive heart failure patients because many of these patients are able to
survive for the long waiting periods required before a suitably matched donor
heart can be found. The Company believes that the development of an artificial
heart would increase the number of lives saved by eliminating the scarcity of,
and waiting period for, available hearts.
 
ABIOMED PRODUCTS AND PRODUCTS UNDER DEVELOPMENT
 
  The Company markets the BVS, which is a temporary cardiac assist device, and
is developing the TAH and the Heart Booster, which are replacement and
permanent cardiac assist devices, respectively.
 
  The BVS-5000 Bi-Ventricular Assist System.  The BVS is a temporary cardiac
assist device designed to provide a patient's failing heart with full
circulatory assistance while allowing the heart to rest, heal and recover its
function. The BVS is most frequently used in patients whose hearts fail to
immediately recover function following heart surgery. In November 1992, the
Company received PMA approval from the FDA for
 
                                      27
<PAGE>
 
the BVS for this post-surgery therapy. In 1996 and 1997, the FDA approved the
use of the BVS for additional indications, expanding its use for the treatment
of all patients with reversible heart failure as a bridge-to-recovery device.
The BVS is the only device that can provide full circulatory assistance
approved by the FDA for the treatment of these patients.
 
  The BVS system is comprised of a microprocessor-based pneumatic drive and
control console, single-use external blood pumps and cannulae. The BVS console
incorporates a closed-loop control system that automatically adjusts the
pumping rate, similar to the natural heart. The dual-chamber blood pumps
provide complete or partial pumping of blood for the left, right or both sides
of a patient's heart and are designed to mimic the function of the natural
heart. The BVS blood pumps reduce the risk of damaging blood cells by filling
the ventricles passively and continuously by gravity rather than by suction.
The cannulae are specially designed tubes used to connect the blood pumps to
the heart. The integration of the cannulae, blood pumps and console creates a
system with the ability to reduce the load on the heart, provide pulsatile
blood flow to vital organs and allow the heart muscles time to rest and
recover. Stabilization of patients who recover under BVS support typically
occurs in a period of less than one week. The BVS is designed to be simple and
easy to use and does not require a specially trained technician to constantly
monitor or adjust the pumping parameters, which can reduce hospital operating
costs.
 
  The following diagram illustrates the BVS.
 
[SCHEMATIC OF PATIENT LYING IN BED ON BVS SUPPORT. COMPONENTS OF THE BVS ARE
IDENTIFIED WITH CAPTIONS.]

                                       28
<PAGE>
 
   
  The BVS is intended for use in any hospital performing open-chest cardiac
surgery, of which there are more than 900 in the United States. As of
September 30, 1997, the BVS had been purchased by over 275 medical centers in
the United States including many of the largest centers. Typically, medical
centers initially purchase the BVS console, two to four BVS single-use blood
pumps, cannulae, training and related accessories. The BVS is capable of
supporting the left, right or both ventricles of the heart. In the Company's
clinical experience, approximately half of the patients required support to
both ventricles of the heart, and therefore the use of two single-use BVS
blood pumps. The Company's United States list price for a BVS console, and a
blood pump and cannulae set are $59,500 and $6,950, respectively.     
 
  The Totally Implantable Artificial Heart (TAH). The Company is developing a
battery-powered totally implantable artificial heart intended as a permanent
replacement device to assume the full pumping function of both the left and
right ventricles of the heart. The TAH is designed for use by patients with
irreparably damaged hearts and at risk of death due to AMI, chronic ischemic
disease or some form of end-stage congestive heart failure but whose vital
organs otherwise remain viable. Included among these patients are those with
massive heart damage or infection, severe rhythm disorders, prosthetic valves,
clots or thrombi in the ventricles, high pulmonary resistance, chronic right
ventricle failure and heart transplant rejection.
 
  The core technology for the TAH has been under development by the Company
since the Company's inception. The Company has completed its feasibility
studies of the TAH system and substantially finalized the design of the TAH.
The system and individual components have been tested through a variety of
laboratory and animal tests. The Company is currently accelerating the
development of the TAH and is devoting significant resources towards improving
the manufacturing process in order to reach consistency and reliability levels
necessary to conduct advanced pre-clinical and clinical trials. The Company's
goal is to initiate clinical trials of the TAH by the end of the year 2000.
There can be no assurance that the Company will be able to successfully
complete pre-clinical testing of the TAH and receive FDA approval to begin
clinical trials of the TAH in a timely manner, if at all. Moreover, pre-
clinical trials may not be predictive of results that will be obtained in
clinical trials. The Company is consulting with regulatory authorities,
leading medical centers and physicians to define protocols and patient
populations for future clinical trials. The Company has built a new
development and pilot-scale manufacturing facility, and has significantly
increased the personnel focused on the manufacturability and testing of the
TAH.
 
  The TAH system is comprised of a thoracic unit, or "replacement heart," a
rechargeable battery, a miniaturized electronics package, a transcutaneous
energy transmission system, and an external belt-worn battery pack. The
thoracic unit includes two artificial ventricles with their associated valves
and a hydraulic pumping system. The unit provides complete pumping of the
blood to the lungs and throughout the body. The ventricles and their
associated valves are being designed and manufactured with seamless surfaces
which reduce the risk of damaging blood cells, or creating clots or thrombi.
The electronics package automatically adjusts the rate and amount of blood
flow to the patient's needs, similar to the natural heart. The implantable
rechargeable battery and the transcutaneous energy transmission system
eliminate the need for wires penetrating the patient's skin and associated
risks of infection. The entire TAH system is being designed to be highly
reliable with minimal maintenance and patient involvement.
 
                                      29
<PAGE>
 
The following diagram illustrates the TAH.
 
 
[SCHEMATIC OF UPPER TORSO OF PATIENT WITH A TAH IMPLANTED. COMPONENTS OF THE TAH
ARE IDENTIFIED WITH CAPTIONS.] 

 
  Much of the development of the TAH has been funded by the NHLBI. Prior to
receiving its most recent $8.5 million TAH Contract extension, the Company
demonstrated to the NHLBI that the basic design of the system functioned in
laboratory and animal models without significant complications. The Company
retains the right to market the resulting TAH without royalty to NHLBI. The
Company is responsible for the complete research and development program and
has collaborated over the past nine years with the Texas Heart Institute for
pre-clinical product testing and evaluation.
 
  The Heart Booster. The Company is developing the Heart Booster as a permanent
cardiac assist device designed to wrap around and help contract the heart
without direct blood contact. The Heart Booster is being designed for use in
patients with congestive heart failure who are not at imminent risk of death,
but whose daily activities are generally restricted due to their weakened
hearts. This device, unlike most devices being developed to pump blood
directly, avoids the potential risks of damage to blood cells and formation of
clots and thrombi. The Heart Booster consists of a pliant and thin artificial
plastic "muscle" that can be wrapped around the heart. This artificial muscle
is being developed to mimic the contraction-relaxation characteristics of the
heart muscle and provide sufficient contractility. The design goal of the Heart
Booster is to restore an acceptable and active quality of life to the patient.
The Heart Booster is in an earlier stage of research and development than the
TAH and is being developed under a five year, $4.3 million contract from the
NHLBI. Columbia Presbyterian Medical Center is collaborating with the Company
on this project for pre-clinical testing and evaluation. There can be no
assurance that the Company will be successful in developing the Heart Booster.
 
                                       30
<PAGE>
 
ABIOMED STRATEGY
 
  The Company's goal is to be a leader in the development, manufacture and
marketing of mechanical cardiac assist and replacement devices that address
the varying needs of a wide range of patients.The Company is pursuing the
following strategies to achieve this objective.
 
  Accelerate Development of the TAH. The Company is devoting significant
resources with the goal to be the first to clinically introduce a totally
implantable artificial heart. The Company is consulting with regulatory
authorities, leading medical centers and physicians to define protocols and
patient populations for future clinical trials. The Company has built a new
development and pilot-scale manufacturing facility, and has significantly
increased the personnel focused on the manufacturability and testing of the
TAH.
   
  Increase Market Penetration of BVS. The Company has recently increased the
size of both its domestic sales force and its clinical support group. Its
sales force focuses on BVS sales to new customers, while its clinical support
group focuses on training and educating existing customers in order to improve
clinical outcomes and increase BVS blood pump usage. As of September 30, 1997,
the BVS had been purchased by over 275 medical centers in the United States,
including many of the largest centers. The Company believes that its
relationships with its customers will facilitate the adoption of the BVS by
other medical centers.     
 
  Maintain and Enhance Technological Leadership. The Company is a leader in
the research and development of mechanical cardiac assist and replacement
devices. The Company has accumulated substantial proprietary knowledge and has
been granted a number of patents relating to the technologies incorporated in
these devices. The Company intends to continue to enhance and expand upon its
core technical expertise to maintain its leadership and to further develop
advanced mechanical cardiac assist and replacement devices.
 
  Pursue Strategic Relationships to Support Research and Commercialization
Efforts. Many of the Company's products under development, including the TAH,
have been funded using government contracts and grants. The Company seeks
funding from third parties to support its research and development programs
and generally limits the use of its own funds until the scientific risk is
reduced. In addition, the Company intends to pursue collaborative
relationships to develop and commercialize the Company's non-cardiac assist
technologies.
 
MARKETING AND SALES
   
  Approximately 900 medical centers in the United States perform heart
surgery. The Company has focused its initial BVS selling efforts on teaching
and transplant centers as well as the medical centers that perform the most
heart surgery procedures. As of September 30, 1997, the BVS had been purchased
by over 275 medical centers in the United States, many of which are within the
group of medical centers initially targeted. The Company believes that its
installed base of customers provides an opportunity for reorders of the
single-use BVS blood pumps as well as a reference base to assist in selling to
new accounts.     
   
  The Company sells the BVS in the United States through direct sales and
clinical support teams. As of September 30, 1997, the Company's BVS sales,
clinical support, marketing and field service teams included 35 full-time
employees. Its sales force focuses on BVS sales to new customers. Its clinical
support group focuses on training and educating existing customers in order to
improve clinical outcomes and increase BVS blood pump usage. The Company
believes the efforts of its clinical support group contribute significantly to
increasing the number of lives saved by the BVS and increasing usage and
reorders of BVS blood pumps. The Company also believes that its sales and
support teams will be key assets for the introduction of potential future
products such as the TAH. Building on its experience in the United States, the
Company also is working to expand its international sales efforts both through
distributors, including a recent collaborative arrangement for distribution in
Japan, and by selling directly in select European markets. The Company
believes that sales of its BVS may be somewhat seasonal, with reduced sales in
the summer months, reflecting hospital personnel and physician vacation
schedules.     
 
 
                                      31
<PAGE>
 
MANUFACTURING
 
  The Company manufactures the BVS console, BVS blood pumps and related
accessories. The manufacture of BVS consoles consists primarily of assembly,
testing and quality control. The Company purchases the majority of the
materials, parts and peripheral components used in the BVS consoles. The
Company manufactures certain blood contacting components for the BVS blood
pumps, including valves and bladders, from its proprietary Angioflex polymer.
 
  The nature of the Company's products requires high quality manufacturing.
The Company's manufacturing and quality testing processes and procedures are
highly dependent on the diligence and experience of the Company's personnel.
To the extent that the Company's manufacturing volumes expand or the Company
begins the manufacture of new products, this dependence on personnel will
likely increase. In addition, the manufacture of blood contacting surfaces of
the Company's products requires a high degree of precision. These surfaces are
manufactured from polyurethane-based materials. The quality and composition of
polyurethane-based products can vary significantly based on numerous factors
including humidity, temperature, material content and air flow during the
manufacturing process. The Company's products also incorporate plastic
components for non-blood contacting surfaces. The Company relies on third-
party vendors to provide these components to the Company's specifications. The
Company is not able to fully inspect the quality of all vendor supplied
components and, therefore, relies on its vendors with respect to the quality
of these components. Once the plastic-based components of the Company's
products have been assembled, accessibility for inspection is limited. If a
defect is detected in as few as one of the Company's products, or in one
component of a Company product, it can result in the recall or restriction on
sale of products. Once assembled, in most cases, the Company's blood
contacting components cannot be reworked for human use. The manufacturing lead
times for parts and assemblies, particularly the polyurethane-based
components, can take many weeks from the date that all materials and
components are received by the Company. In addition, vendor lead times for
materials and components of the Company's products vary significantly, with
lead times for certain materials and components exceeding six months.
 
  The Company is planning to expand its manufacturing facility for the BVS
during the next twelve months. There can be no assurance that the products
manufactured in the expanded facility will be manufactured at the same cost
and quality as the BVS is currently being manufactured. In addition, to the
extent that the Company's products under development have been manufactured,
they have been manufactured as prototypes with, at most, pilot-scale
production. The Company's products under development are likely to involve
additional manufacturing complexities and high quality requirements. There can
be no assurance that the Company will be able to increase production of the
BVS or manufacture future products, if developed and approved, in commercial
quantities on a consistent and timely basis, with acceptable cost and quality.
The inability to manufacture current and future products in sufficient
quantities in a timely manner, and with acceptable cost and quality, would
have a material adverse effect on the Company's business, financial condition
and results of operations.
 
  The Company relies on outside vendors to supply certain components used in
the BVS and in its products under development. Certain of the components of
the BVS are supplied by sole source vendors or are custom made for the
Company. From time to time, suppliers of certain components of the BVS have
indicated that they intend to discontinue, or have discontinued, making such
components. In addition, certain of these components are supplied from single
sources due to quality considerations, costs or constraints imposed by
regulatory authorities. There are relatively few additional sources of supply
for such components and establishing additional or replacement suppliers for
such components cannot be accomplished quickly and may require FDA approval.
In the past, certain suppliers have announced that, due to government
regulation or in an effort to reduce potential product liability exposure,
they intend to limit or terminate sales of certain products to the medical
industry. There can be no assurance that, if such an interruption were to
occur, the Company would be able to find suitable alternative supplies at
reasonable prices or would be able to obtain requisite regulatory approvals in
a timely manner, if at all. Similarly, when and if the Company reaches the
clinical testing stage of its products under development, it may find that
certain components become more
 
                                      32
<PAGE>
 
difficult to source from outside vendors due to the product liability risk
perceived by those vendors. The Company's inability to obtain acceptable
components in a timely manner or to find suitable replacements at an
acceptable cost would have a material adverse effect on the Company's
business, financial condition and results of operations.
 
RESEARCH AND PRODUCT DEVELOPMENT
 
  The Company has substantial expertise in electro-mechanical systems, cardiac
physiology and experimental surgery, blood-material interactions, fluid
mechanics and hemodynamics, internal and external electronic hardware,
software, plastics processing, lasers and optical physics. The Company's
research and development efforts are focused on the development of new
products, primarily related to mechanical cardiac assist and heart
replacement, and the continued enhancement of the BVS and related
technologies. The Company's research and development personnel also are
involved in establishing protocols, monitoring and submitting test data to the
FDA and corresponding foreign regulatory agencies to obtain the necessary
clearances and approvals for its products. Sophisticated tools, such as 3-
dimensional CAD/CAM, and procedures are used in an effort to ensure smooth
transition of new products from research to product development to
manufacturing.
 
  Cardiac assist products currently under development by the Company include
the TAH, the Heart Booster, and a variety of specialized pumps, such as a
miniaturized rotary blood pump and a magnetically-suspended centrifugal pump.
The Company is also developing devices in the area of minimally invasive
surgery applications, such as tissue welding and vascular welding for the
repair of small arteries.
   
  During the six months ended September 30, 1997 and the fiscal years ended
March 31, 1997, 1996 and 1995, the Company expended $3.7 million, $3.8
million, $3.2 million and $2.5 million, respectively, on research and
development. A substantial portion of these expenses were funded by government
contracts and grants. See "Management's Discussion and Analysis of Financial
Condition and Results of Operations" and "Business--Strategic Relationships."
    
STRATEGIC RELATIONSHIPS
 
 Genzyme
 
  In July 1997, the Company sold 1,153,846 shares of Common Stock to Genzyme
Corporation ("Genzyme"). In connection with this sale, the Company and Genzyme
agreed to discuss collaborative arrangements that would allow them to jointly
develop and commercialize products which combine biotechnology and biomedical
engineering, primarily for the surgical market. A potential target for
collaboration is minimally invasive cardiac surgery, an emerging field in
which surgeons use new products and techniques to reduce the trauma, recovery
period, and expense of heart surgery. The Company and Genzyme are engaged in
ongoing discussions regarding this potential collaboration. The Chief
Executive Officer of Genzyme is a member of the Company's board of directors.
There can be no assurance that the Company and Genzyme will agree to jointly
collaborate on any project, that any such project would result in the
development of any product, or that any such product, if developed, would be
commercially successful. See "Certain Transactions."
 
 National Heart, Lung and Blood Institute
   
  Since the Company's inception, United States government agencies,
particularly the NHLBI, have provided significant support to the Company's
product development efforts. The most significant current funding from the
NHLBI supports the Company's development of the TAH and Heart Booster. In
September 1996, the Company received an $8.5 million extension to its TAH
Contract from the NHLBI. In September 1995, the Company received a $4.3
million contract from the NHLBI to develop the Heart Booster. During the six
months ended September 30, 1997 and the fiscal years ended March 31, 1997,
1996 and 1995, the     
 
                                      33
<PAGE>
 
   
Company recognized revenues of $3.7 million, $4.2 million, $3.1 million and
$2.3 million, respectively, under United States government contracts and
grants. All of the Company's government contracts and grants contain
provisions making them terminable at the convenience of the government and are
subject to government appropriations. There can be no assurance that the
government will not terminate, reduce or delay the funding for any of the
Company's contracts. In addition, there can be no assurance that the Company
will be successful in obtaining any new government contracts or further
extensions to existing contracts.     
 
COMPETITION
 
  Competition in the cardiac assist market is intense and subject to rapid
technological change and evolving industry requirements and standards. Many of
the companies developing or marketing cardiac assist products have
substantially greater financial, product development, sales and marketing
resources and experience than the Company. These competitors may develop
superior products or products of similar quality at the same or lower prices.
Moreover, there can be no assurance that improvements in current or new
technologies will not make them technically equivalent or superior to the
Company's products in addition to providing cost or other advantages. Other
advances in medical technology, biotechnology and pharmaceuticals may reduce
the size of the potential markets for the Company's products or render those
products obsolete.
 
  The BVS is the only device that can provide full circulatory assistance
approved by the FDA as a bridge-to-recovery device for the treatment of
patients with reversible heart failure. However, the Company is aware of at
least one other company, Thoratec Laboratories Corporation, seeking approval
of a temporary cardiac assist device to address this market. Approval by the
FDA of products that compete directly with the BVS would increase competitive
pricing and other pressures and could have a material adverse effect on the
Company's business, financial condition and results of operations. The Company
believes that it would compete with any such product on the basis of cost,
clinical outcome and customer relations. There can be no assurance that the
Company would be able to compete effectively with respect to these factors.
 
  The Company is aware of other artificial heart development efforts in the
United States, Canada, Europe and Japan. A team comprised of Pennsylvania
State University and 3M Corporation, Inc. has been developing a heart
replacement device for many years with significant NHLBI support. There are a
number of companies, including Thermo Cardiosystems, Inc. and Novacor, a
division of Baxter International, Inc., which are developing permanent cardiac
assist products, including implantable left ventricular assist devices and
miniaturized rotary ventricular assist devices, that may address markets that
overlap with certain segments of the markets targeted by the Company's TAH.
The Company's TAH may compete with those VADs for some patient groups, notably
patients with severe congestive heart failure due to predominant left
ventricle dysfunction. An implantable VAD supplements the pumping ability of a
failing ventricle. In contrast, the TAH is being designed to replace failing
ventricles. The Company believes that Thermo Cardiosystems, Inc. has commenced
clinical testing for PMA approval of LVADs for permanent cardiac assist. The
Company believes that the TAH, LVADs and other VADs, if developed, will
generally be used to address the needs of different patient populations, with
an overlap for certain segments of the heart failure population. There can be
no assurance that the Company will develop and receive FDA approval to market
its TAH on a timely basis, if at all, or that once developed, the TAH will be
commercially successful.
 
  The Company's customers frequently have limited budgets. As a result, the
Company's products compete against the broad range of medical devices for
these limited funds. The Company's success will depend in large part upon its
ability to enhance its existing products and to develop new products to meet
regulatory and customer requirements and to achieve market acceptance. The
Company believes that important competitive factors with respect to the
development and commercialization of its products include the relative speed
with which it can develop products, establish clinical utility, complete
clinical testing and regulatory approval processes, obtain reimbursement and
supply commercial quantities of the product to the market. There can be no
assurance that the Company will be able to compete successfully or that
competition will not have a material adverse effect on the Company's business,
financial condition and results of operations.
 
                                      34
<PAGE>
 
THIRD-PARTY REIMBURSEMENT
 
  The Company's BVS product is, and most of its products under development are
intended to be, sold to medical institutions. Medical institutions and their
physicians typically seek reimbursement for the use of these products from
third-party payors, including Medicare, Medicaid, private health insurers and
managed care organizations. As a result, market acceptance of the Company's
current and proposed products may depend in large part on the extent to which
reimbursement is available to medical institutions and their physicians for
use of the Company's products.
 
  The level of reimbursement provided by United States and foreign third-party
payors varies according to a number of factors, including the medical
procedure category, payor, location, outcome and cost. In the United States,
many private health care insurance carriers follow the recommendations of
HCFA, which establishes guidelines for the reimbursement of health care
providers treating Medicare and Medicaid patients. Internationally, healthcare
reimbursement systems vary significantly. In certain countries, medical center
budgets are fixed regardless of levels of patient treatment. In other
countries, such as Japan, reimbursement from government or third party payors
must be applied for and approved. As of the date of this Prospectus, under
HCFA guidelines, Medicare reimburses medical institutions for Medicare
patients based on the category of surgical procedures in which the BVS is used
and incrementally reimburses physicians for the use of the BVS. Medicare does
not, however, currently reimburse medical institutions for the incremental
cost of using the BVS above the amount allowed for the reimbursement category
of the surgical procedure. Certain private health insurers and managed care
providers provide incremental reimbursement to both the medical institutions
and their physicians. The Company is currently petitioning HCFA to assign a
higher paying reimbursement category whenever the BVS is used. In October
1995, HCFA established a special "ICD-9" code for the BVS in an effort to more
clearly track and evaluate hospital and physician costs associated
specifically with the BVS compared to current reimbursement levels, so that
HCFA can determine the appropriate category and level of reimbursement. There
can be no assurance that HCFA will reassign the BVS to a higher paying
category in a timely manner, if at all.
 
  No reimbursement levels have been established for the Company's products
under development, including the TAH. Prior to approving coverage for new
medical devices, most third-party payors require evidence that the product has
received FDA approval or clearance for marketing, is safe and effective and
not experimental or investigational, and is medically necessary and
appropriate for the specific patient for whom the product is being used.
Increasing numbers of third-party payors require evidence that the procedures
in which the products are used, as well as the products themselves, are cost-
effective. There can be no assurance that the Company's products under
development will meet these criteria, that third-party payors will reimburse
physicians and medical institutions for the use of the products or that the
level of reimbursement will be sufficient to support the widespread use of the
products. Furthermore, there can be no assurance that third-party payors will
continue to provide reimbursement for the use of BVS or that such payors will
not reduce the current level of reimbursement for the product. Failure to
achieve adequate reimbursement for its current or proposed products would have
a material adverse effect on the Company's business, financial condition and
results of operations.
 
ABIODENT SUBSIDIARY
   
  ABIODENT, Inc. ("ABIODENT"), a wholly owned subsidiary of the Company,
manufactures and markets the PerioTemp periodontal screening system
("PerioTemp") and markets the Halimeter for early detection and assessment of
risk of periodontal disease and other sources of halitosis. ABIODENT is
operated independently from the Company's cardiac assist activities. As of
September 30, 1997, ABIODENT employed eight full-time employees.     
 
  The PerioTemp is a tool for use by dentists, periodontists and other dental
specialists to instantly detect sites of gum inflammation. The PerioTemp
patented technology, developed in part through funding from the National
Institute of Dental Research, consists of a book-sized console, containing a
microprocessor that is
 
                                      35
<PAGE>
 
connected to a probe, shaped much like a dentist's probe, with a heat-sensing
tip. The device is used in a manner which is consistent with traditional
probing but includes an instantaneous display and record of temperature
deviations from normal inside the pockets between teeth and the surrounding
gum. According to published sources, gum temperature has been shown to be a
reliable indicator of the presence of inflammation, a precursor of periodontal
disease. The PerioTemp also allows the clinician to record gum pocket depth
and bleeding point information.
 
  ABIODENT markets the PerioTemp in conjunction with the Halimeter, to provide
differential evaluation of the sources of halitosis. ABIODENT purchases the
Halimeter from Interscan, Inc. under a distribution arrangement which is
exclusive to ABIODENT if it meets certain defined sales volume levels.
 
  ABIODENT markets its dental products with complementary products of others
used in preventive and cosmetic dental programs. Revenues from this subsidiary
have represented less than ten percent of the Company's total revenues in all
periods presented in this Prospectus. The Company believes that it cannot
alone adequately support the investment that the continued growth of its
dental business requires and is looking for alternative ways to support its
dental business.
 
PATENTS AND PROPRIETARY RIGHTS
 
  The Company's business depends significantly upon its proprietary
technology. The Company relies on a combination of trade secret laws, patents,
copyrights, trademarks and confidentiality agreements and other contractual
provisions to establish, maintain and protect its proprietary rights, all of
which afford only limited protection. There can be no assurance that others
will not independently develop substantially equivalent proprietary
information and techniques or otherwise gain access to the Company's trade
secrets or disclose such technology or that the Company can meaningfully
protect its trade secrets.
 
  The Company has been issued or allowed 22 patents and has pending three
patent applications in the United States. The Company has obtained or applied
for corresponding patents and patent applications for certain of these patents
and patent applications in a limited number of foreign countries. These
patents relate to the BVS and certain of its products under development
including the TAH. The Company's United States patents expire at various times
from 2003 to 2016. There can be no assurance that the Company's pending patent
applications or any future applications will be approved, that any patents
will provide the Company with competitive advantages or will not be challenged
by third parties, or that the patents of others will not render the Company's
patents obsolete or otherwise have an adverse effect on the Company's ability
to conduct business. Because foreign patents may afford less protection under
foreign law than is available under United States patent law, there can be no
assurance that any such patents issued to the Company will adequately protect
the Company's proprietary information. Others may have filed and may file
patent applications in the future that are similar or identical to those of
the Company. To determine the priority of inventions, the Company may have to
participate in interference proceedings declared by the United States Patent
and Trademark Office or opposition proceedings before a foreign patent office
that could result in substantial cost to the Company. No assurance can be
given that any such interfering patent or patent application will not have
priority over patent applications filed on behalf of the Company or that the
Company will prevail in any opposition proceeding.
   
  The medical device industry is characterized by a large number of patents
and by frequent and substantial intellectual property litigation. There can be
no assurance that the Company's products and technologies do not infringe any
patents or proprietary rights of third parties. The Company has in the past
and may in the future be notified that it may be infringing intellectual
property rights possessed by others. Any intellectual property litigation
would be costly and could divert the efforts and attention of the Company's
management and technical personnel, which could have a material adverse effect
on the Company's business, financial condition and results of operations.
There can be no assurance that infringement claims will not be asserted in the
future or such assertions, if proven to be true, will not prevent the Company
from selling its products or materially and adversely affect the Company's
business, financial condition and results of     
 
                                      36
<PAGE>
 
operations. If any such claims are asserted against the Company's intellectual
property rights, it may seek to enter into a royalty or licensing arrangement.
There can be no assurance, however, that a license will be available on
reasonable terms, or at all. The Company could decide, in the alternative, to
resort to litigation to challenge such claims or to design around the patented
technology. Such actions could be costly and would divert the efforts and
attention of the Company's management and technical personnel, which would
materially and adversely affect the Company's business, financial condition
and results of operations.
   
  The Company has recently received a letter from a third party alleging that
certain technology incorporated into the transcutaneous energy transmission
system component of the Company's TAH may infringe the patent or other
intellectual property rights of that party. The Company is in the preliminary
stages of assessing the allegations, but does not believe that it is
infringing any patent or other intellectual property rights of this third
party. There can be no assurance that the Company would prevail in the defense
of an infringement claim, if made. If infringement of the proprietary rights
of the third party were determined to exist, the Company would either be
required to use or develop alternative technology or to seek a license of the
technology. There can be no assurance that the Company could obtain a license
of this technology on a timely basis or on reasonable terms, if at all. In
addition, there can be no assurance that the Company could develop or license
alternative technology on a timely basis, if at all. As a result, a
determination of infringement could have a material adverse affect on the
Company's development of the TAH and on its business, financial condition and
results of operations. Any patent or intellectual property dispute or
litigation could result in product development delays, would be costly and
could divert the efforts and attention of the Company's management and
technical personnel, and could have a material adverse effect on the Company's
business, financial condition and results of operations.     
 
  Certain of the Company's products have been developed in part under
government contracts pursuant to which the Company may be required to
manufacture a substantial portion of the product in the United States and the
government may obtain certain rights to use or disclose technical data
developed under those contracts. The Company retains the right to obtain
patents on any inventions developed under those contracts (subject to a non-
exclusive, non-transferable, royalty-free license to the government), provided
it follows certain prescribed procedures.
 
  The Company purchased certain of its technology, including technology
incorporated in the BVS, from the Abiomed Limited Partnership (the
"Partnership"), in which the Company has a 61.7% interest. As a result of this
purchase, the Company is required to pay the Partnership a royalty through
August 3, 2000. See Note 7 to the Consolidated Financial Statements.
 
GOVERNMENT REGULATION
 
  Clinical testing, manufacture and sale of the Company's products and
products under development, including the BVS, TAH and Heart Booster and the
Company's dental devices, are or will be subject to regulation by the FDA and
corresponding state and foreign regulatory agencies. Noncompliance with
applicable requirements can result in, among other things, fines, injunctions,
civil penalties, recall or seizure of products, total or partial suspension of
production, failure of the government to grant pre-market clearance or pre-
market approval for devices, withdrawal of marketing approvals and criminal
prosecution. The FDA also has the authority to request repair, replacement or
refund of the cost of any device manufactured or distributed by the Company.
   
  In the United States, medical devices are classified into one of three
classes (i.e., Class I, II or III) on the basis of the controls deemed
necessary by the FDA to reasonably ensure their safety and effectiveness.
Class I devices are subject to general controls, such as labeling, pre-market
notification and adherence to the FDA's Current Good Manufacturing Practices
requirements set forth in the Quality System Regulation ("QSR"), which include
testing, control and documentation requirements. Class II devices are subject
to general and special controls, such as performance standards, post-market
surveillance, patient registries and QSR compliance. Class III devices, which
are typically life-sustaining, life-supporting and implantable devices, or new
devices that have been found not to be substantially equivalent to legally
marketed devices, are subject to the requirements applicable to Class I and
Class II devices and must generally also receive pre-market approval by the
FDA to ensure their safety and effectiveness.     
 
                                      37
<PAGE>
 
  Before introducing a new device into the market, the Company must generally
obtain FDA clearance or approval through either clearance of a 510(k)
notification or receipt of a Pre-Market Approval ("PMA"). A 510(k) clearance
will be granted if the submitted information establishes that the proposed
device is "substantially equivalent" to a legally marketed Class I or Class II
medical device or a Class III medical device for which the FDA has not required
PMAs. The Company has received FDA market clearance under Section 510(k) for
the PerioTemp.
 
  A PMA application must be filed if a proposed device is not substantially
equivalent to a legally marketed Class I or Class II device, or if it is a
Class III device for which the FDA has required PMAs. A PMA application must be
supported by valid scientific evidence, which typically includes extensive
information including relevant bench tests, laboratory and animal studies and
clinical trial data to demonstrate the safety and effectiveness of the device.
The PMA application also must contain a complete description of the device and
its components, a detailed description of the methods, facilities and controls
used to manufacture the device, and the proposed labeling advertising
literature and training materials. By regulation, the FDA has 180 days to
review the PMA application, and during that time an advisory committee may
evaluate the application and provide recommendations to the FDA. Advisory
Committee reviews often occur over a significantly protracted period, and a
number of devices for which FDA approval has been sought have never been
cleared for marketing. In addition, modifications to a device that is the
subject of an approved PMA, or to its labeling or manufacturing process, may
require approval by the FDA, including the submission of PMA supplements or new
PMAs.
 
  If clinical trials of a device are required in order to obtain FDA approval
and the device presents a "significant risk," the sponsor of the trial will
have to file an Investigational Device Exemption ("IDE") application prior to
commencing clinical trials. The IDE application must be supported by data,
which typically includes the results of animal and laboratory testing. If the
IDE application is approved by the FDA and all of the appropriate Institutional
Review Boards ("IRBs"), clinical trials may begin at a specific number of
investigational sites with a specific number of patients, as approved by the
FDA. If the device presents a "nonsignificant risk" to the patient, a sponsor
may begin the clinical trial after obtaining approval for the study by one or
more appropriate IRBs without the need for FDA approval. Sponsors of clinical
trials are permitted to charge for investigational devices distributed in the
course of the study provided that compensation does not exceed recovery of the
costs of manufacture, research, development and handling. An IDE supplement
must be submitted to and approved by the FDA before a sponsor or investigator
may make a change to the investigational plan that may affect its scientific
soundness or the rights, safety or welfare of human subjects.
 
  In November 1992, the Company received PMA approval from the FDA for the BVS.
In 1996 and 1997, the FDA approved the use of the BVS for additional
indications, expanding its use to the treatment of all patients with reversible
heart failure. The TAH and the Heart Booster will be Class III devices and
therefore will be subject to the IDE and PMA processes and the QSR.
 
  Any devices, including the BVS, that are manufactured or distributed by the
Company pursuant to FDA clearances or approvals are subject to pervasive and
continuing regulation by the FDA and certain state agencies. Manufacturers of
medical devices for marketing in the United States are required to adhere to
the QSR and must also comply with Medical Devices Reporting ("MDR")
requirements that a firm report to the FDA any incident in which its product
may have caused or contributed to a death or serious injury, or in which its
product malfunctioned and, if the malfunction were to recur, it would be likely
to cause or contribute to a death or serious injury. Labeling and promotional
activities are subject to scrutiny by the FDA and, in certain circumstances, by
the Federal Trade Commission. Current FDA enforcement policy prohibits the
marketing of approved medical devices for unapproved uses. The Company is
subject to routine inspection by the FDA and certain state agencies for
compliance with the QSR and MDR requirements, as well as other applicable
regulations.
 
  In addition, the FDA requires that manufacturers of certain devices,
including the BVS, conduct postmarket surveillance studies after receiving
approval of a PMA application. The primary purpose of required postmarket
surveillance is to provide an early warning system to alert the health care
community to
 
                                       38
<PAGE>
 
any potential problems with a device within a reasonable time of the initial
marketing of the device. Postmarket surveillance provides clinical monitoring
of the early experiences with the device once it is distributed in the general
population under actual conditions of use.
 
  The Company is also subject to regulation in each of the foreign countries in
which it sells its products. Many of the regulations applicable to the
Company's products in these counties are similar to those of the FDA. The
Company has obtained the requisite foreign regulatory approvals for sale of the
BVS in many foreign countries, including most of Western Europe, and has
recently commenced the regulatory approval process in Japan. The Company
believes that foreign regulations relating to the manufacture and sale of
medical devices are becoming more stringent. The European Union has adopted
regulations requiring that medical devices comply with the Medical Device
Directive by June 15, 1998, which includes ISO-9001 and CE certification. The
Company's BVS currently has German MedGV approval but is not yet certified for
ISO-9001 compliance. The Company is working to obtain ISO-9001 and independent
CE certification for its BVS facility. There can be no assurance that the
Company will obtain such certification in a timely manner, if at all. Unless
ISO and CE certification are obtained, the Company's sale of the BVS into the
European Union may be restricted. Many manufacturers of medical devices,
including the Company, have often relied on foreign markets for the initial
commercial introduction of their products. The more stringent foreign
regulatory environment could make it more difficult, costly and time consuming
for the Company to pursue this strategy for new products.
 
  Any FDA, foreign or state regulatory approvals or clearances, once obtained,
can be withdrawn or modified. Delay in the Company obtaining, or inability of
the Company to obtain and maintain, any necessary United States or foreign
clearances or approvals for new or existing products or product enhancements,
or cost overruns resulting from these regulatory requirements, would have a
material adverse effect on the Company's business, financial condition and
results of operations.
 
EMPLOYEES
   
  As of September 30, 1997, the Company had 166 full-time employees. The
Company has entered into contractual agreements with all of its employees which
include strict confidentiality and non-compete commitments by each employee.
None of the Company's employees is represented by a union. The Company
considers its employee relations to be good.     
 
PROPERTIES
 
  The Company leases its headquarters and research and development and
production facilities in three separate buildings in an industrial office park
covering approximately 55,000 square feet. The addresses of these leased spaces
are 33 Cherry Hill Drive and 24 Cherry Hill Drive in Danvers, Massachusetts and
66 Cherry Hill Drive in Beverly, Massachusetts. All facilities are located
approximately 22 miles north of Boston. The leases at the primary facilities,
representing 23,000 square feet and 22,000 square feet, respectively, expire in
April 2000 and June 2001, respectively. All leases have options to extend at
market rates.
 
  The Company's facilities include fabrication areas for medical and dental
device manufacturing, and development facilities for laboratory and durability
testing of plastics and electronics. The Company has begun improving
approximately 18,000 square feet of this space to better accommodate its BVS
growth and to allow for expanded engineering, production and testing relating
to the TAH. The Company believes that these facilities are adequate for its
current needs.
 
LEGAL PROCEEDINGS
 
  The Company is not a party to any material pending legal proceedings.
 
                                       39
<PAGE>
 
                                  MANAGEMENT
 
EXECUTIVE OFFICERS, KEY EMPLOYEES AND DIRECTORS
 
  The Company's executive officers, key employees and directors are as
follows:
 
<TABLE>   
<CAPTION>
                   NAME                  AGE                TITLE
   ------------------------------------- --- ------------------------------------
   <S>                                   <C> <C>
   David M. Lederman, Ph.D*............. 53  Chairman of the Board of Directors,
                                              President, Chief Executive Officer
                                              and Assistant Treasurer
   Robert T.V. Kung, Ph.D*.............. 53  Senior Vice President--Research and
                                              Development, and Assistant
                                              Secretary
   Eugene D. Rabe*...................... 41  Vice President--Global Sales,
                                              Marketing and Clinical Programs
   John F. Thero*....................... 37  Vice President--Finance, Chief
                                              Financial Officer, Treasurer and
                                              Assistant Secretary
   Anthony W. Bailey.................... 41  Vice President--Engineering
   William J. Bolt...................... 45  Vice President (in charge of
                                              ABIODENT)
   David Nikka.......................... 42  Vice President--Resources and
                                              Administration
   Janice Piasecki...................... 43  Vice President--Regulatory Affairs
   Edward G. Taylor, Ph.D............... 46  Vice President--Program Director,
                                              Implantable Artificial Heart
   W. Gerald Austen, M.D................ 67  Director
   Paul Fireman......................... 53  Director
   John F. O'Brien...................... 54  Director
   Desmond H. O'Connell, Jr. ........... 61  Director
   Henri A. Termeer..................... 51  Director
</TABLE>    
- --------
*Executive Officer
 
  Dr. David M. Lederman founded the Company in 1981, has served as Chairman of
the Board and Chief Executive Officer since that time, and as President for
the majority of that time. Prior to founding ABIOMED, he was Chairman of the
Medical Research Group at the Everett Subsidiary of Avco Corporation. He
originated the design and development of ABIOMED's artificial heart blood
pumps and their valves, has authored over 40 medical publications, is a member
of numerous medical and scientific professional organizations and has been a
frequent speaker in forums on cardiac support systems and on the financing and
commercialization of advanced medical technology. Dr. Lederman received a
Ph.D. degree in Aerospace Engineering from Cornell University.
 
  Dr. Robert T.V. Kung has served as Vice President of Research and
Development of the Company since 1987. From 1982 to 1987, he served as Chief
Scientist of the Company. Since 1995, Dr. Kung has served as the Senior Vice
President of the Company. Prior to joining ABIOMED, he was a Principal
Research Scientist at Schafer Associates and at the Avco Everett Research
Laboratory. He developed non-linear optical techniques for laser applications
and investigated physical and chemical phenomena in re-entry physics. Dr. Kung
has been Principal Investigator for the Company's TAH and Heart Booster
programs and has conceived of and directed the development of the Company's
laser-based minimally invasive technologies, as well as the PerioTemp. Dr.
Kung received a Ph.D. degree in Physical Chemistry from Cornell University.
 
  Mr. Eugene D. Rabe joined the Company in 1993, as its Vice-President for
Sales. In 1996, he assumed responsibility for all domestic sales, clinical and
field support. Recently he was promoted to Vice-President Global Sales,
Marketing and Clinical Programs. Prior to joining ABIOMED, he was Vice-
President, Sales and
 
                                      40
<PAGE>
 
Marketing for Endosonics Corporation before which he was a Sales Manager for
St. Jude Medical, Inc. He has been involved in the sales and marketing of
cardiovascular/cardiological devices for over ten years. Mr. Rabe received a
Bachelor's degree from St. Cloud State University and his MBA from the
University of California.
 
  Mr. John F. Thero joined the Company in 1994 as Vice President, Finance and
Administration and Chief Financial Officer. Prior to joining ABIOMED, during
the period 1992 to 1995, Mr. Thero was Chief Financial Officer and acting
President for the restructuring of two venture-backed companies. From 1987 to
1992, Mr. Thero was employed, in various capacities including Chief Financial
Officer, by Aries Technology, Inc. From 1983 to 1987, Mr. Thero was employed
by the commercial audit division of Arthur Andersen & Co. during which time he
became a Certified Public Accountant. Mr. Thero received a B.A. in
Economics/Accounting from The College of the Holy Cross.
 
  Mr. Anthony W. Bailey joined the Company in 1997 to lead the Electronics
System Development of the Implantable Artificial Heart Program and is
currently Vice President--Engineering. Prior to joining ABIOMED, during 1987
to 1997, Mr. Bailey was Vice President and General Manager for Pace Medical,
Inc., a manufacturer of external pacemakers, rhythm management analyzers and
accessories. From 1982 to 1987, he was Manager of Design and Development at
Shiley Infusaid, Inc., a manufacturer of implantable drug pumps and infusion
ports. Prior to that, Mr. Bailey served in various engineering functions with
manufacturers of implantable pacemakers, data acquisition and control systems
and medical monitoring equipment. Mr. Bailey received his Bachelor's degree
from University of Lowell.
 
  Mr. William J. Bolt joined the Company in 1982. Since that time, he has
served in various roles, from Director of Operations to Vice President of
Engineering, and was the engineer in-charge when the BVS and PerioTemp systems
were developed. He is presently responsible for the business operations of
ABIODENT, including dental product sales, marketing, manufacturing and
engineering support. Mr. Bolt received a Bachelor's degree in Electrical
Engineering and a Masters degree in Business Administration from Northeastern
University.
 
  Mr. David Nikka joined the Company in 1997 as its Vice President--Resources
and Administration. Prior to joining ABIOMED, he was Vice President, Human
Resources from 1991 to 1997 for Genzyme Genetics, Director of Human Resources
from 1989 to 1991 for Genzyme Corporation and Director of Human Resources for
Integrated Genetics from 1986 to 1989. Mr. Nikka received his Bachelor Degree
from Boston University. Mr. Nikka is past Chairperson of both the BIO and the
Massachusetts Biotechnology Council Human Resource Committees.
 
  Ms. Janice Piasecki joined the Company in 1991 as Manager of Clinical
Research and Regulatory Affairs. In this role she has worked extensively on
PMA submissions for the BVS which led to FDA approvals. She was promoted to
Vice-President, Regulatory Affairs in 1994. Prior to joining ABIOMED, she held
position of Investigator for the United States Food and Drug Administration
and Manager of Regulatory Affairs for C.R. Bard. Ms. Piasecki received her
B.S. degree in Biology and Chemistry from Boston College.
 
  Dr. Edward G. Taylor joined the Company at the end of 1996 as Vice President
and Director of the Artificial Heart Program. Prior to joining ABIOMED, Dr.
Taylor worked in the United States Air Force from 1972 to 1996 where he
attained the rank of Colonel and was most recently the Program Director for
the Airborne Warning and Control System (AWACS) in the United States, Europe
and Japan. Previously he had directed high technology research and development
of nationally significant defense programs, including self-protection avionics
for Air Force One. He was also involved in the launch and operation of
reconnaissance and communication satellites. Dr. Taylor holds a Bachelor's
degree from the Illinois Institute of Technology, a Master's degree from the
Air Force Institute of Technology and a Ph.D. degree in Estimation and Control
from the Massachusetts Institute of Technology.
 
                                      41
<PAGE>
 
  Dr. W. Gerald Austen has served as a director of the Company since 1985.
From 1969 to the present, Dr. Austen has been Chief of the Surgical Services
at Massachusetts General Hospital, and from 1974 to the present, has been the
Edward D. Churchill Professor of Surgery at Harvard Medical School. He became
President of the Massachusetts General Physicians Organization in 1994. Dr.
Austen is the former President of the American College of Surgeons, the
American Association for Thoracic Surgery, the American Surgical Association
and the Massachusetts and American Heart Associations. Dr. Austen is a member
of the Institute of Medicine of the National Academy of Sciences, a Fellow of
the American Academy of Arts and Sciences and a life member of the corporation
of the Massachusetts Institute of Technology.
 
  Mr. Paul Fireman has served as a director of the Company since 1987. He is
the founder of Reebok International Ltd., a leading worldwide designer,
marketer and distributor of sports, fitness and casual footwear, apparel and
equipment. Mr. Fireman has served as Chief Executive Officer and a director of
that company since 1979, as Chairman of the Board of Directors since 1985 and
President from 1979 to 1987 and since 1989. Mr. Fireman has also served as the
chairman of the Entrepreneurial Advisory Board of Babson College since 1995.
 
  Mr. John F. O'Brien has served as a director since 1989. Since August 1989
he has been the President and Chief Executive Officer and a director of First
Allmerica Financial Life Insurance Company (formerly State Mutual Life
Assurance Company of America). Since January 1995 he has been President, Chief
Executive Officer and a Director of Allmerica Financial Corporation, a
financial services holding company. Mr. O'Brien is also President, Chief
Executive Officer and a director of Allmerica Property & Casualty Companies,
Inc.; Chairman of the Board, President and Chief Executive Officer of Citizens
Corporation; and a trustee and Chairman of the Board of Allmerica Securities
Trust, Allmerica Investment Trust and Allmerica Funds. From 1972 until 1989,
Mr. O'Brien was employed by Fidelity Investments in various capacities,
including as Group Managing Director of FMR Corp. Mr. O'Brien is also a
director of Cabot Corporation and TJX Companies, Inc. and a Trustee of the
Worcester Art Museum.
 
  Mr. Desmond H. O'Connell, Jr. has served as a director of the Company since
1995. He has been an independent management consultant since September 1990
and has served as a director of Chryslais International Corporation, an
international contract research organization, since 1991. From December 1992
until December 1993, he served as the Chairman, Management Committee, of
Pharmakon Research International, Inc., a provider of pre-clinical testing
services to pharmaceutical biotechnology companies. During 1991, he briefly
served as Chairman of the Board and Chief Executive Officer of Osteotech,
Inc., a medical products company. Mr. O'Connell was with the BOC Group, PLC,
an industrial gas and health care company, in senior management positions from
1980 to 1990 and was a member of the Board of Directors of BOC Group, PLC from
1983 to 1990. From April 1990 until September 1990, Mr. O'Connell was
President and Chief Executive Officer of BOC Health Care. From 1986 to April
1990, he was Group Managing Director of BOC Group, PLC. Prior to joining BOC,
Mr. O'Connell held various positions at Baxter Laboratories, Inc. including
chief executive of the Therapeutic and Diagnostic Division and Vice President,
Corporate Development.
 
  Mr. Henri A. Termeer has served as a director of the Company since 1987. Mr.
Termeer has served as President and a director of Genzyme, a biotechnology
company engaged in the production and marketing of human health care products,
since 1983, as its Chief Executive Officer since 1985, and as its Chairman of
the Board since 1988. Mr. Termeer is also Chairman of the Board of Genzyme
Transgenics Corporation. He is also a director of AutoImmune, Inc., GelTex
Pharmaceuticals, Inc. and Diacrin, Inc. and serves as a trustee of Hambrecht &
Quist Healthcare Investors and Hambrecht & Quist Life Sciences Investors.
 
 
                                      42
<PAGE>
 
                             CERTAIN TRANSACTIONS
 
  In July 1997, the Company sold a total of 1,242,710 shares of Common Stock
to Genzyme and certain of the Company's directors for a purchase price of
$13.00 per share, for a total purchase price of $16.2 million. The Chief
Executive Officer of Genzyme, Henri A. Termeer, is a director of the Company.
Of the shares sold, 1,153,846 shares were sold to Genzyme, 23,480 shares were
sold to Paul Fireman, 7,692 shares were sold to Desmond H. O'Connell, Jr. and
57,692 shares were sold to John F. O'Brien. In addition, simultaneously with
this transaction, David M. Lederman, the President and Chief Executive Officer
of the Company sold 153,846 shares of Common Stock to Paul Fireman, a director
of the Company. In connection with these transactions, the Company granted
Genzyme certain registration rights with respect to the shares of Common Stock
purchased by Genzyme. Commencing in July 1998, Genzyme may on up to three
occasions require the Company to register not less than 25% of Genzyme's
shares of Common Stock. Genzyme has also been granted certain piggyback
registration rights to participate in underwritten public offerings by the
Company, subject to certain limitations, commencing in July 1998. In addition,
the other purchasers received similar piggyback registration rights commencing
in July 1998, with respect to the 242,710 shares of Common Stock purchased by
them. In connection with its purchase of the Common Stock, Genzyme agreed,
subject to certain limited exceptions, not to acquire additional voting
securities of the Company for a period of five years following the
consummation of the transaction without the consent of the Company, and,
during that five year period, to vote its shares in the same proportion as
votes cast by other stockholders of the Company or, in Genzyme's discretion,
in accordance with the recommendations of the Company's Board of Directors.
 
                                      43
<PAGE>
 
                      PRINCIPAL AND SELLING STOCKHOLDERS
   
  The following table sets forth certain information regarding the beneficial
ownership of the Company's Common Stock as of September 30, 1997, and as
adjusted to reflect the sale of the Common Stock offered hereby, (i) by each
person who is known by the Company to own beneficially more than 5% of the
outstanding shares of Common Stock, (ii) by each executive officer and
director of the Company, (iii) by all executive officers and directors of the
Company as a group and (iv) by each of the Selling Stockholders. This
information is based upon information received from or on behalf of the named
individuals. All Selling Stockholders are executive officers of the Company.
    
<TABLE>   
<CAPTION>
                           BENEFICIAL OWNERSHIP   NUMBER   BENEFICIAL OWNERSHIP
                           PRIOR TO OFFERING(1)     OF       AFTER OFFERING(1)
                          ----------------------- SHARES  -----------------------
                          NUMBER OF PERCENTAGE OF  BEING  NUMBER OF PERCENTAGE OF
                           SHARES     OWNERSHIP   OFFERED  SHARES     OWNERSHIP
                          --------- ------------- ------- --------- -------------
<S>                       <C>       <C>           <C>     <C>       <C>
David M. Lederman,
 Ph.D(2)................  1,322,554     16.0%     115,000 1,207,554     11.5%
Genzyme Corporation.....  1,153,846     14.0%         --  1,153,846     11.0%
Robert T.V. Kung,
 Ph.D(3)(4).............    173,188      2.1%      35,000   138,188      1.3%
Eugene D. Rabe(4).......     18,750       *           --     18,750       *
John F. Thero(4)........      7,764       *           --      7,764       *
W. Gerald Austen,
 M.D.(4)................     25,400       *           --     25,400       *
Paul Fireman(4).........    225,226      2.7%         --    225,226      2.1%
John F. O'Brien(4)......     85,092      1.0%         --     85,092       *
Desmond H. O'Connell,
 Jr.(4).................     18,092       *           --     18,092       *
Henri A. Termeer(4)(5)..  1,179,246     14.2%         --  1,179,246     11.2%
All executive officers
 and directors as a
 group(2)(3)(4)(5) (9
 persons)...............  3,055,312     36.2%     150,000 2,905,312     27.2%
</TABLE>    
- --------
 *Represents beneficial ownership of less than 1% of the outstanding shares of
Common Stock.
   
(1) Beneficial ownership is determined in accordance with the rules of the
    Securities and Exchange Commission and generally includes voting or
    investment power with respect to securities. Beneficial ownership also
    includes shares of stock subject to options currently exercisable or
    exercisable within 60 days of September 30, 1997. Percentage of beneficial
    ownership is based on 8,264,556 shares of Common Stock outstanding on
    September 30, 1997 and 10,514,556 shares of Common Stock outstanding upon
    completion of this offering. Unless otherwise noted, each person
    identified possesses sole voting and investment power with respect to the
    shares listed.     
(2) Includes 725,923 shares held by Dr. Lederman's wife, as to which Dr.
    Lederman disclaims beneficial ownership.
(3) Includes 60,000 shares held by Dr. Kung's wife and 12,000 shares held in
    trust for the benefit of certain relatives of Dr. Kung, as to which Dr.
    Kung disclaims beneficial ownership.
   
(4) Includes the following shares subject to options which are exercisable
    within 60 days after September 30, 1997: Dr. Kung--51,188; Mr. Rabe--
    18,750; Mr. Thero--7,500; Dr. Austen--25,000; Mr. Fireman--25,000; Mr.
    O'Brien--25,000; Mr. O"Connell--5,000; Mr. Termeer--25,000.     
(5) Includes 1,153,846 shares held by Genzyme Corporation as to which Mr.
    Termeer disclaims beneficial ownership. Mr. Termeer is the Chief Executive
    Officer of Genzyme.
 
                                      44
<PAGE>
 
                         DESCRIPTION OF CAPITAL STOCK
   
  As of September 30, 1997, the Company's authorized capital stock consisted
of 25,000,000 shares of Common Stock, $.01 par value, and 1,000,000 shares of
Class B Preferred Stock, $.01 par value ("Preferred Stock").     
 
COMMON STOCK
   
  As of September 30, 1997, there were 8,264,556 shares of Common Stock
outstanding. These shares were held of record by approximately 340
stockholders, including multiple beneficial holders at depositories, banks and
brokers listed as a single holder in the street name of each respective
depository, bank or broker. There will be 10,514,556 shares of Common Stock
outstanding after giving effect to the sale of the shares of Common Stock
offered hereby by the Company.     
 
  The holders of Common Stock are entitled to one vote per share on all
matters to be voted on by stockholders and are entitled to receive dividends,
if any, as may be declared from time to time by the Board of Directors from
funds legally available therefore. Upon liquidation or dissolution of the
Company, the holders of Common Stock are entitled to receive all assets
available for distribution to the stockholders, subject to any preferential or
other rights of the holders of Preferred Stock. The Common Stock has no
preemptive or other subscription rights, and there are no conversion rights or
redemption or sinking fund provisions with respect to such shares. The holders
of Common Stock do not have cumulative voting rights in the election of
directors. All of the shares of Common Stock are, and the shares to be sold in
the offering will be, fully paid and nonassessable.
 
PREFERRED STOCK
 
  The Company has no Preferred Stock outstanding. The Board of Directors has
the authority to issue the Preferred Stock in one or more series and to fix
the dividend rights, dividend rate, conversion rights, voting rights, rights
and terms of redemption, liquidation preferences, sinking fund terms and other
rights, preferences, privileges and restrictions of any series of Preferred
Stock, the number of shares constituting any such series and the designation
thereof, without further vote or action by the stockholders. The Board of
Directors may, without stockholder approval, issue Preferred Stock with rights
and privileges which could, among other things, have the effect of delaying,
deferring or preventing a change in control of the Company. The issuance of
Preferred Stock with voting and conversion rights may adversely affect the
voting power and other rights of the holders of Common Stock, including the
loss of voting control to others. The Company currently has no plans to issue
any of the Preferred Stock. The Board of Directors has designated 25,000
shares of the Preferred Stock as the "Series A Junior Participating Preferred
Stock" in connection with the Rights described below.
 
ANTI-TAKEOVER EFFECT OF PROVISIONS OF THE CERTIFICATE OF INCORPORATION AND BY-
LAWS, RIGHTS DISTRIBUTION AND DELAWARE LAW
 
 Certificate of Incorporation and By-laws
 
  The Certificate of Incorporation includes several provisions in addition to
the Preferred Stock, which may render more difficult an unfriendly tender
offer, proxy contest, merger or other change in control of the Company. These
provisions are intended to enhance the likelihood of continuity and stability
in the composition of the Board of Directors and in the policies formulated by
the Board of Directors and to discourage certain types of transactions that
may involve an actual or threatened change of control of the Company. These
provisions are also designed to reduce the vulnerability of the Company to
unsolicited acquisition proposals and to discourage certain tactics that may
be used in proxy fights. However, such provisions could have the effect of
discouraging others from making tender offers for the shares of Common Stock
and, as a consequence, they also may inhibit fluctuations in the market price
of the shares of Common Stock which could result from actual or rumored
takeover attempts. Such factors also may have the effect of preventing changes
in the management of the Company.
 
 
                                      45
<PAGE>
 
  The Certificate of Incorporation (i) provides for the classification of the
Company's Board of Directors into three classes, (ii) eliminates the ability
of stockholders to enlarge the Board of Directors, (iii) provides that
vacancies in the office of a director shall be in the first instance filled by
the remaining directors, except in the case of the directors elected by the
Common Stock voting as a separate class, in which case it shall be filled by
the holders of that class voting as a separate class, (iv) provides that
directors may only be removed "for cause" and only by the class or classes of
stock which elected them, and (v) requires an 80% affirmative vote of all
votes entitled to be cast to amend the preceding provisions. The
classification of directors has the effect of making it more difficult to
change the composition of the Board of Directors. At least two stockholder
meetings, instead of one, are required to effect a change in the control of
the Board.
 
  The By-laws provide that advance written notice of any stockholder
nomination for director must be provided not less than 45 nor more than 60
days prior to the anticipated date of the annual meeting for election of
directors.
 
  The Certificate of Incorporation explicitly directs the Board of Directors
to take into account all relevant factors in exercising its business judgment
in determining what is in the best interests of the Company and its
stockholders in evaluating certain tender offers and business combination
proposals. Relevant factors include, without limitation, the Board's estimate
of the future value of the Company, the resources and future prospects of the
other party, and the possible social, legal, environmental and economic
effects on the Company and on the employees, customers, suppliers and
creditors of the Company and on the communities in which the Company's
facilities are located.
 
  The Certificate of Incorporation and the By-laws also provide that all
stockholder action must be effected at a duly called meeting and not by
written consent.
 
  The authority of the Board of Directors to issue authorized but unissued
shares of Common Stock might be considered as having the effect of
discouraging an attempt by another person or entity to effect a takeover or
otherwise gain control of the Company since the issuance of additional shares
of Common Stock would dilute the voting power of the Common Stock then
outstanding.
 
 Rights Distribution
 
  On August 13, 1997, the Board of Directors declared a dividend of one
preferred share purchase right (a "Right") for each outstanding share of
Common Stock on August 28, 1997 (the "Record Date") to the stockholders of
record on that date. Each Right entitles the registered holder to purchase
from the Company one one-thousandth of a share of Series A Junior
Participating Preferred Stock, par value $0.01 per share (the "Preferred
Shares"), of the Company, at a price of $90.00 per one one-thousandth of a
Preferred Share, subject to adjustment.
 
  Subject to certain limited exceptions until the earlier to occur of (i) ten
days following a public announcement that a person or group of affiliated or
associated persons (an "Acquiring Person") has acquired beneficial ownership
of 15% or more of the outstanding shares of Common Stock, or (ii) ten business
days (or such later date as may be determined by action of the Board of
Directors prior to such time as any person becomes an Acquiring Person)
following the commencement of, or announcement of an intention to make, a
tender offer or exchange offer the consummation of which would result in the
beneficial ownership by a person or group of 15% or more of the outstanding
shares of Common Stock (the earlier of such dates being called the
"Distribution Date"), the Rights will be evidenced by the Common Stock
certificates with a copy of the Summary of Rights attached thereto. As soon as
practicable following the Distribution Date, the rights will become
exercisable, separate certificates evidencing the Rights ("Right
Certificates") will be mailed to stockholders of record on the Distribution
Date and the separate Right Certificates alone will evidence the Rights. The
Rights will expire on the earlier of (i) August 13, 2007 or (ii) the date on
which the Rights are redeemed.
 
                                      46
<PAGE>
 
  In the event that any person becomes an Acquiring Person, proper provision
will be made so that each holder of a Right, other than Rights beneficially
owned by the Acquiring Person and its affiliates and associates (which will
thereafter be void), will thereafter have the right to receive upon exercise,
that number of shares of Common Stock having a market value of two times the
exercise price of the Right. In the event that, at any time after a person
becomes an Acquiring Person, the Company is acquired in a merger or other
business combination transaction or 50% or more of its consolidated assets or
earning power are sold, proper provision will be made so that each holder of a
Right will thereafter have the right to receive, upon the exercise thereof at
the then current exercise price of the Right, that number of shares of common
stock of the acquiring company which at the time of such transaction will have
a market value of two times the exercise price of the Right.
 
  At any time after any person becomes an Acquiring Person and prior to the
acquisition by any person or group of a majority of the outstanding shares of
Common Stock, the Board of Directors may exchange the Rights (other than Rights
owned by such person or group which have become void), in whole or in part, at
an exchange ratio of one share of Common Stock per Right, subject to
adjustment. At any time prior to the time any Person becomes an Acquiring
Person, the Board of Directors of the Company may redeem the Rights in whole,
but not in part, at a price of $0.001 per Right (the "Redemption Price"). The
redemption of the Rights may be made effective at such time, on such basis and
with such conditions as the Board of Directors in its sole discretion may
establish. Immediately upon any redemption of the Rights, the right to exercise
the Rights will terminate and the only right of the holders of Rights will be
to receive the Redemption Price.
 
  The terms of the Rights may be amended by the Board of Directors without the
consent of the holders of the Rights, except that from and after such time as
any person becomes an Acquiring Person no such amendment may adversely affect
the interests of the holders of the Rights (other than the Acquiring Person and
its affiliates and associates).
 
 Delaware Takeover Statute
 
  Pursuant to Delaware law, Delaware corporations are prohibited from engaging
in a wide range of specified transactions with any "interested stockholder,"
defined to include, among others, any person or entity who in the last three
years obtained 15% or more of any class or series of stock entitled to vote
generally in the election of directors, unless, among other exceptions, the
transaction is approved by (i) the Board of Directors prior to the date the
interested stockholder obtained such status or (ii) the holders of two-thirds
of the outstanding shares of each class or series of stock entitled to vote
generally in the election of directors, not including those shares owned by the
interested stockholder. By virtue of the Company's decision not to opt out of
the provisions of this law, it applies to the Company.
 
TRANSFER AGENT AND REGISTRAR
 
  The Transfer Agent and Registrar for the Common Stock is Boston EquiServe LP.
 
                                       47
<PAGE>
 
                                 UNDERWRITING
   
  The Underwriters named below, acting through their representatives
BancAmerica Robertson Stephens and UBS Securities LLC (the "Representatives"),
have severally agreed, subject to the terms and conditions of the Underwriting
Agreement, to purchase from the Company and the Selling Stockholders the
number of shares of Common Stock set forth opposite their names below. The
Underwriters are committed to purchase and pay for all such shares, if any are
purchased.     
 
<TABLE>   
<CAPTION>
                                                                       NUMBER OF
   UNDERWRITER                                                          SHARES
   -----------                                                         ---------
   <S>                                                                 <C>
   BancAmerica Robertson Stephens.....................................
   UBS Securities LLC.................................................
                                                                       ---------
       Total.......................................................... 2,400,000
                                                                       =========
</TABLE>    
 
  The Representatives have advised the Company and the Selling Stockholders
that the Underwriters propose to offer the shares of Common Stock to the
public at the price to the public set forth on the cover page of this
Prospectus and to certain dealers at such price less a concession of not more
than $   per share, of which $   may be reallowed to other dealers. After the
public offering, the public offering price, concession and reallowance to
dealers may be reduced by the Representatives. No such reduction shall change
the amount of proceeds to be received by the Company and Selling Stockholders
as set forth on the cover page of this Prospectus.
 
  The Company has granted to the Underwriters an option, exercisable during
the 30-day period after the date of this Prospectus, to purchase up to 360,000
additional shares of Common Stock at the same price per share as the Company
and Selling Stockholders will receive for the 2,400,000 shares that the
Underwriters have agreed to purchase. To the extent that the Underwriters
exercise such option, each of the Underwriters will have a firm commitment to
purchase approximately the same percentage of such additional shares that the
number of shares of Common Stock to be purchased by it shown in the above
table represents as a percentage of the 2,400,000 shares offered hereby. If
purchased, such additional shares will be sold by the Underwriters on the same
terms as those on which the 2,400,000 shares are being sold. The Company will
be obligated, pursuant to the option, to sell shares to the Underwriters to
the extent the option is exercised. The Underwriters may exercise such option
only to cover over-allotments made in connection with the sale of shares of
Common Stock offered hereby.
 
 
                                      48
<PAGE>
 
  The Underwriting Agreement contains covenants of indemnity among the
Underwriters, the Company and the Selling Stockholders against certain civil
liabilities, including liabilities under the Securities Act and liabilities
arising from breaches of representations and warranties contained in the
Underwriting Agreement.
   
  The Company's executive officers, directors, Genzyme and each of the Selling
Stockholders who, in the aggregate hold approximately 2,872,874 shares of
Common Stock (2,722,874 shares of Common Stock after the sale of shares of
Common Stock by the Selling Stockholders in the offering) have agreed in
writing with the Representatives that, for a period of 90 days from the date
of this Prospectus ("Lock-up Period"), subject to certain limited exceptions,
each will not, directly or indirectly, without the prior written consent of
BancAmerica Robertson Stephens, sell, offer, contract to sell, pledge, grant
any option to purchase or otherwise dispose of any shares of Common Stock or
any securities convertible into or exchangeable for, or any rights to purchase
or acquire, Common Stock held by them, thereafter acquired by them or which
may be deemed to be beneficially owned by them. However, BancAmerica Robertson
Stephens may, in its sole discretion at any time or from time to time, without
notice, release all or any portion of the securities subject to the lock-up
agreements. In addition, the Company has agreed that during the Lock-up
Period, it will not, without the prior written consent of BancAmerica
Robertson Stephens, issue, sell, contract to sell or otherwise dispose of any
shares of Common Stock, any options or warrants to purchase any shares of
Common Stock or any securities convertible into, exercisable for or
exchangeable for shares of Common Stock other than the Company's sale of
shares in this offering, the issuance of Common Stock upon the exercise of
outstanding options and under the Company's existing employee stock purchase
plan, the Company's issuance of options under existing employee and director
stock options plans and under certain other conditions. See "Risk Factors--
Shares Eligible For Future Sale."     
 
  The offering price for the Common Stock has been determined by negotiations
among the Company, the Selling Stockholders and the Representatives of the
Underwriters, based largely upon the market price for the Common Stock as
reported on the Nasdaq National Market.
 
  The Underwriters do not intend to confirm sales to any accounts over which
they exercise discretionary authority in excess of 5% of the number of shares
of Common Stock offered hereby.
 
  The Representatives have advised the Company that, pursuant to Regulation M
under the Securities Act, certain persons participating in the offering may
engage in transactions, including stabilizing bids, syndicate covering
transactions or the imposition of penalty bids, which may have the effect of
stabilizing or maintaining the market price of the Common Stock at a level
above that which might otherwise prevail in the open market. A "stabilizing
bid" is a bid for or the purchase of the Common Stock on behalf of the
Underwriters for the purpose of fixing or maintaining the price of the Common
Stock. A "syndicate covering transaction" is the bid for or the purchase of
the Common Stock on behalf of the Underwriters to reduce a short position
incurred by the Underwriters in connection with the offering. A "penalty bid"
is an arrangement permitting the Representatives to reclaim the selling
concession otherwise accruing to an Underwriter or syndicate member in
connection with the offering if the Common Stock originally sold by such
Underwriter or syndicate member is purchased by the Representatives in a
syndicate covering transaction and has therefore not been effectively placed
by such Underwriter or syndicate member. The Representatives have advised the
Company that such transactions may be effected on the Nasdaq National Market
or otherwise and, if commenced, may be discontinued at any time.
 
  In connection with this offering, certain Underwriters may engage in passive
market making transactions in the Common Stock on the Nasdaq Stock Market in
accordance with Rule 103 of Regulation M under the Securities Exchange Act of
1934 ("Exchange Act"). Passive market making consists of displaying bids on
the Nasdaq National Market limited by the bid prices of independent market
makers and making purchases limited by such prices and effected in response to
order flow. Net purchases by a passive market maker on each day are limited to
a specific percentage of the passive market maker's average daily trading
volume in the Common Stock during a specific period and must be discontinued
when such limit is reached. Passive market making may stabilize the market
price of the Common Stock at a level above that which might otherwise prevail
and, if commenced, may be discontinued at any time.
 
 
                                      49
<PAGE>
 
  Since September 1996, an entity affiliated with UBS Securities LLC has
managed certain assets of the Company, primarily in the form of marketable
securities, held by ABD Holding, Inc., a wholly owned subsidiary of the
Company. The Company pays quarterly fees for such services based on a
percentage of the assets managed. UBS Securities LLC also received fees in
connection with its role as the Company's financial advisor in connection with
the implementation of a stockholder rights plan for the holders of the
Company's Common Stock in August 1997 and its opinion as to the fairness from
a financial point of view of the consideration received by the Company
pursuant to a private placement of the Company's Common Stock in July 1997.
See "Certain Transactions."
       
                                 LEGAL MATTERS
 
  The validity of the securities offered hereby has been passed upon for the
Company and the Selling Stockholders by Brown, Rudnick, Freed & Gesmer,
Boston, Massachusetts. Certain legal matters in connection with this offering
will be passed upon for the Underwriters by Testa, Hurwitz & Thibeault, LLP,
Boston, Massachusetts. A member of Brown, Rudnick, Freed & Gesmer, counsel to
the Company, is the Secretary of the Company.
 
                                    EXPERTS
 
  The financial statements included or incorporated by reference in this
Prospectus or elsewhere in this Registration Statement have been audited by
Arthur Andersen LLP, independent public accountants, as indicated in their
report with respect thereto, and are included or incorporated by reference
herein upon the authority of said firm as experts in giving said report.
 
                             AVAILABLE INFORMATION
 
  The Company is subject to the informational requirements of the Exchange
Act, and in accordance therewith files reports, proxy statements and other
information with the Commission. Such reports, proxy statements and other
information filed by the Company can be inspected and copied at the public
reference facilities maintained by the Commission at 450 Fifth Street, NW,
Room 1024, Judiciary Plaza, Washington, D.C. 20549, and at the Commission's
Regional Offices at Citicorp Center, 500 West Madison Street, Suite 1400,
Chicago, Illinois 60661 and 7 World Trade Center, Suite 1300, New York, New
York 10048, at prescribed rates. In addition, such reports, proxy statements
and information are available through the Commission's Electronic Data
Gathering and Retrieval System at http://www.sec.gov. The Company's Common
Stock is listed on the Nasdaq National Market, and reports, proxy statements
and certain other information concerning the Company can also be inspected at
the offices of the Nasdaq National Market, 1735 K Street NW, Washington, D.C.
20006.
 
  The Company has filed with the Commission a Registration Statement on Form
S-3 under the Securities Act of 1933, as amended, with respect to the Common
Stock being offered hereby. This Prospectus, which constitutes a part of the
Registration Statement, does not contain all of the information set forth in
such Registration Statement and the exhibits and schedules thereto to which
reference is hereby made. The statements in this Prospectus as to the contents
of such Registration Statement are qualified in their entirety by such
reference. The Registration Statement, together with its exhibits and
schedules, may be inspected without charge at the Public Reference Section of
the Commission in Washington, D.C. at the address noted above, and copies of
all or any part thereof may be obtained from the Commission upon payment of
the prescribed fees.
 
                                      50
<PAGE>
 
                INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE
 
  The following documents filed by the Company with the Commission pursuant to
the Exchange Act are incorporated herein by reference:
 
    (1) the Company's Annual Report on Form 10-K for the fiscal year ended
  March 31, 1997;
     
    (2) the Company's Quarterly Reports on Form 10-Q for the fiscal quarters
  ended June 30 and September 30, 1997;     
 
    (3) the Company's Current Report on Form 8-K filed with the Commission on
  August 25, 1997; and
 
    (4) the description of the Company's Common Stock and the Rights
  contained in the Company's Registration Statements on Form 8-A filed with
  the Commission on June 11, 1987 and August 25, 1997.
 
  All reports and other documents subsequently filed by the Company pursuant
to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act after the date of
this Prospectus and prior to the termination of the offering shall be deemed
to be incorporated by reference in this Prospectus and shall be part hereof
from the date of the filing of such document. Any statement contained in a
document incorporated or deemed to be incorporated by reference herein shall
be deemed to be modified or superseded for purposes of this Prospectus to the
extent that a statement contained herein, or in any other subsequently filed
document that also is (or is deemed to be) incorporated by reference herein,
modifies or supersedes such statement. Any statement so modified or superseded
shall not be deemed, except as so modified or superseded, to constitute a part
of the Registration Statement or this Prospectus. The Company will provide
without charge to each person, including any beneficial owner, to whom this
Prospectus is delivered, upon written or oral request of such person, a copy
of any of the documents referred to above (other than exhibits). Requests for
such documents should be submitted in writing to: Investor Relations, ABIOMED,
Inc., Cherry Hill Drive, Danvers, Massachusetts 01923, or by telephone at
(978) 777-5410.
 
                                      51
<PAGE>
 
                         ABIOMED, INC. AND SUBSIDIARIES
 
                   INDEX TO CONSOLIDATED FINANCIAL STATEMENTS
 
<TABLE>   
<CAPTION>
                                                                            PAGE
                                                                            ----
<S>                                                                         <C>
Report of Independent Public Accountants..................................  F-2
Consolidated Balance Sheets as of March 31, 1996 and 1997 and September
 30, 1997 (unaudited).....................................................  F-3
Consolidated Statements of Operations for the Fiscal Years Ended March 31,
 1995, 1996 and 1997 and for the Six Months Ended September 30, 1996 and
 1997 (unaudited).........................................................  F-4
Consolidated Statements of Stockholders' Investment for the Fiscal Years
 Ended March 31, 1995, 1996 and 1997 and for the Six Months Ended
 September 30, 1997 (unaudited)...........................................  F-5
Consolidated Statements of Cash Flows for the Fiscal Years Ended March 31,
 1995, 1996 and 1997 and for the Six Months Ended September 30, 1996 and
 1997 (unaudited).........................................................  F-6
Notes to Consolidated Financial Statements................................  F-7
</TABLE>    
 
                                      F-1
<PAGE>
 
                        ABIOMED, INC. AND SUBSIDIARIES
 
                   REPORT OF INDEPENDENT PUBLIC ACCOUNTANTS
 
To ABIOMED, Inc.:
 
  We have audited the accompanying consolidated balance sheets of ABIOMED,
Inc. (a Delaware corporation) and subsidiaries as of March 31, 1996 and 1997,
and the related consolidated statements of operations, stockholders'
investment and cash flows for each of the three years in the period ended
March 31, 1997. These financial statements are the responsibility of the
Company's management. Our responsibility is to express an opinion on these
financial statements based on our audits.
 
  We conducted our audits in accordance with generally accepted auditing
standards. Those standards require that we plan and perform the audit to
obtain reasonable assurance about whether the financial statements are free of
material misstatement. An audit includes examining, on a test basis, evidence
supporting the amounts and disclosures in the financial statements. An audit
also includes assessing the accounting principles used and significant
estimates made by management, as well as evaluating the overall financial
statement presentation. We believe that our audits provide a reasonable basis
for our opinion.
 
  In our opinion, the financial statements referred to above present fairly,
in all material respects, the financial position of ABIOMED, Inc. and
subsidiaries as of March 31, 1996 and 1997, and the results of their
operations and their cash flows for each of the three years in the period
ended March 31, 1997, in conformity with generally accepted accounting
principles.
 
                                          Arthur Andersen LLP
 
Boston, Massachusetts
May 8, 1997
 
                                      F-2

<PAGE>
 
                         ABIOMED, INC. AND SUBSIDIARIES
 
                          CONSOLIDATED BALANCE SHEETS
 
<TABLE>   
<CAPTION>
                                               MARCH 31,           SEPTEMBER 30,
                                       --------------------------  -------------
                                           1996          1997          1997
                                       ------------  ------------  -------------
                                                                    (unaudited)
<S>                                    <C>           <C>           <C>
                            ASSETS
Current Assets:
  Cash and cash equivalents (Note
   1)................................  $  2,938,332  $  1,616,696  $     711,425
  Short-term marketable securities
   (Note 1)..........................     7,709,110     7,744,664     23,600,089
  Accounts receivable, net of
   allowance for doubtful accounts of
   $111,000, $229,000 and $231,000 at
   March 31, 1996, 1997 and September
   30, 1997, respectively............     2,606,289     4,816,500      6,257,797
  Inventories (Note 1)...............     1,653,512     1,820,783      1,847,624
  Prepaid expenses and other current
   assets............................        92,280       173,172        391,383
                                       ------------  ------------  -------------
    Total current assets.............    14,999,523    16,171,815     32,808,318
                                       ------------  ------------  -------------
Property and Equipment, at cost (Note
 1):
  Machinery and equipment............     2,378,851     3,147,837      3,981,322
  Furniture and fixtures ............       156,048       241,867        380,242
  Leasehold improvements.............       378,998     1,118,677      1,262,937
                                       ------------  ------------  -------------
                                          2,913,897     4,508,381      5,624,501
  Less -- Accumulated depreciation
   and amortization..................     2,331,145     2,618,603      2,988,902
                                       ------------  ------------  -------------
                                            582,752     1,889,778      2,635,599
Other Assets, net (Notes 1 and 7):          627,154       485,000        904,286
                                       ------------  ------------  -------------
                                       $ 16,209,429  $ 18,546,593  $  36,348,203
                                       ============  ============  =============
           LIABILITIES AND STOCKHOLDERS' INVESTMENT
Current Liabilities:
  Accounts Payable...................  $    777,943  $  1,289,024  $   1,132,730
  Accrued expenses (Notes 8 and 9)...     1,486,981     2,032,506      2,567,027
                                       ------------  ------------  -------------
    Total current liabilities........     2,264,924     3,321,530      3,699,757
                                       ------------  ------------  -------------
Commitments (Notes 5 and 7)
Stockholders' Investment (Notes 2 and
 6):
  Class B Preferred Stock, $.01 par
   value --
   Authorized -- 1,000,000 shares
   issued and outstanding-- none.....           --            --             --
  Common Stock, $.01 par value --
    Authorized --25,000,000 shares
   issued and outstanding --
   5,518,054, 7,008,282 and 8,264,556
   shares at March 31, 1996, March
   31, 1997 and September 30, 1997,
   respectively......................        55,180        70,082         82,646
  Class A Common Stock, $.01 par
   value --
   Authorized -- 2,346,000 shares
   issued and outstanding-- 1,428,000
   shares at March 31, 1996 and none
   at March 31, 1997 and September
   30, 1997, respectively............        14,280           --
Additional paid-in capital...........    36,625,221    37,169,893     53,221,747
Accumulated deficit..................   (22,750,176)  (22,014,912)  (20,655,947)
                                       ------------  ------------  -------------
Total stockholders' investment.......    13,944,505    15,225,063     32,648,446
                                       ------------  ------------  -------------
                                       $ 16,209,429  $ 18,546,593  $  36,348,203
                                       ============  ============  =============
</TABLE>    
 
  The accompanying notes are an integral part of these consolidated financial
                                  statements.
 
                                      F-3
<PAGE>
 
                         ABIOMED, INC. AND SUBSIDIARIES
 
                     CONSOLIDATED STATEMENTS OF OPERATIONS
 
<TABLE>   
<CAPTION>
                                                                  SIX MONTHS ENDED
                               YEARS ENDED MARCH, 31,               SEPTEMBER 30,
                         ------------------------------------- -----------------------
                            1995         1996         1997        1996        1997
                         -----------  -----------  ----------- ----------- -----------
                                                               (unaudited) (unaudited)
<S>                      <C>          <C>          <C>         <C>         <C>
Revenues (Note 1):
  Products.............. $ 6,892,931  $ 9,725,332  $12,311,178 $5,759,555  $9,324,205
  Contracts.............   2,337,505    3,118,278    4,150,752  1,753,849   3,680,252
                         -----------  -----------  ----------- ----------  ----------
                           9,230,436   12,843,610   16,461,930  7,513,404  13,004,457
                         -----------  -----------  ----------- ----------  ----------
Costs and expenses:
  Cost of products......   3,288,833    3,921,319    5,360,449  2,122,853   3,437,803
  Research and
   development
   (Note 1).............   2,464,519    3,218,211    3,832,918  1,780,737   3,654,181
  Selling, general and
   administrative.......   4,278,392    5,740,830    7,068,403  3,229,235   4,970,150
                         -----------  -----------  ----------- ----------  ----------
                          10,031,744   12,880,360   16,261,770  7,132,825  12,062,134
                         -----------  -----------  ----------- ----------  ----------
Income (loss) from
 operations.............    (801,308)     (36,750)     200,160    380,579     942,323
  Interest and other
   income...............     449,124      527,874      535,104    256,537     416,642
                         -----------  -----------  ----------- ----------  ----------
Net income (loss)....... $  (352,184) $   491,124  $   735,264 $  637,116  $1,358,965
                         ===========  ===========  =========== ==========  ==========
Net income (loss) per
 common and common
 equivalent share (Note
 1)..................... $     (0.05) $      0.07  $      0.10 $     0.09  $     0.17
                         ===========  ===========  =========== ==========  ==========
Weighted average number
 of common and common
 equivalent shares
 outstanding (Note 1)...   6,511,777    6,995,664    7,162,347  7,196,343   7,868,675
                         ===========  ===========  =========== ==========  ==========
</TABLE>    
 
 
 
  The accompanying notes are an integral part of these consolidated financial
                                  statements.
 
                                      F-4
<PAGE>
 
                         ABIOMED, INC. AND SUBSIDIARIES
 
              CONSOLIDATED STATEMENTS OF STOCKHOLDERS' INVESTMENT
 
<TABLE>   
<CAPTION>
                                                   CLASS A
                            COMMON STOCK         COMMON STOCK
                         ------------------- --------------------- ADDITIONAL                    TOTAL
                          NUMBER     $0.01     NUMBER      $0.01     PAID-IN   ACCUMULATED   STOCKHOLDERS'
                         OF SHARES PAR VALUE OF SHARES   PAR VALUE   CAPITAL     DEFICIT      INVESTMENT
                         --------- --------- ----------  --------- ----------- ------------  -------------
<S>                      <C>       <C>       <C>         <C>       <C>         <C>           <C>
Balance, March 31,
 1994................... 4,432,686  $44,327   2,040,000   $20,400  $33,413,242 $(22,889,116)  $10,588,853
 Stock options
  exercised.............     1,100       11         --        --         6,314          --          6,325
 Stock issued under
  employee stock
  purchase plan.........       639        7         --        --         3,873          --          3,880
 Stock issued in
  exchange for amount
  due to Abiomed Limited
  Partnership...........   451,427    4,514         --        --     3,053,341          --      3,057,855
 Net loss...............       --       --          --        --           --      (352,184)     (352,184)
                         ---------  -------  ----------   -------  ----------- ------------   -----------
Balance, March 31,
 1995................... 4,885,852   48,859   2,040,000    20,400   36,476,770  (23,241,300)   13,304,729
 Conversion of Class A
  Common Stock to Common
  Stock.................   612,000    6,120    (612,000)   (6,120)         --           --            --
 Stock options
  exercised.............    19,425      194         --        --       143,018          --        143,212
 Stock issued under
  employee stock
  purchase plan.........       777        7         --        --         5,433          --          5,440
 Net income.............       --       --          --        --           --       491,124       491,124
                         ---------  -------  ----------   -------  ----------- ------------   -----------
Balance, March 31,
 1996................... 5,518,054   55,180   1,428,000    14,280   36,625,221  (22,750,176)   13,944,505
 Conversion of Class A
  Common Stock to Common
  Stock................. 1,428,000   14,280  (1,428,000)  (14,280)         --           --            --
 Stock options
  exercised.............    59,112      611         --        --       533,142          --        533,753
 Stock issued to
  directors and under
  employee stock
  purchase plan.........     3,116       11         --        --        11,530          --         11,541
 Net income.............       --       --          --        --           --       735,264       735,264
                         ---------  -------  ----------   -------  ----------- ------------   -----------
Balance, March 31,
 1997................... 7,008,282   70,082         --        --    37,169,893  (22,014,912)   15,225,063
 Stock options
  exercised.............    12,015      120         --        --        83,448          --         83,568
 Stock issued under
  employee stock
  purchase plan.........     1,549       17         --        --        15,764          --         15,781
 Private placement of
  Common Stock ......... 1,242,710   12,427         --        --    15,952,642          --     15,965,069
 Net income.............       --       --          --        --           --     1,358,965     1,358,965
                         ---------  -------  ----------   -------  ----------- ------------   -----------
Balance, September 30,
 1997 (unaudited)....... 8,264,556   82,646         --        --    53,221,747  (20,655,947)   32,648,446
</TABLE>    
 
  The accompanying notes are an integral part of these consolidated financial
                                  statements.
 
                                      F-5
<PAGE>
 
                         ABIOMED, INC. AND SUBSIDIARIES
 
                     CONSOLIDATED STATEMENTS OF CASH FLOWS
 
<TABLE>   
<CAPTION>
                                                                     SIX MONTHS
                                                                        ENDED
                                YEARS ENDED MARCH 31,               SEPTEMBER 30,
                           ----------------------------------  ------------------------
                             1995        1996        1997         1996         1997
                           ---------  ----------  -----------  -----------  -----------
                                                               (unaudited)  (unaudited)
<S>                        <C>        <C>         <C>          <C>          <C>
Cash flows from operating
 activities:
 Net income (loss).......  $(352,184) $  491,124  $   735,264  $  637,116   $ 1,358,965
 Adjustments to reconcile
  net income (loss) to
  net cash provided by
  (used in) operating
  activities --
  Depreciation and
   amortization..........    353,293     349,756      429,612     192,168       441,376
  Noncash transactions
   related to Abiomed
   Limited Partnership...   (251,883)        --           --          --            --
  Changes in current
   assets and
   liabilities --
   Accounts receivable...    (73,518)   (830,555)  (2,210,211)   (337,286)   (1,441,297)
   Inventories...........    815,518    (244,232)    (167,271)   (164,591)      (26,841)
   Prepaid expenses and
    other current
    assets...............     58,530     (38,450)     (80,892)   (112,073)     (708,574)
   Accounts payable......    (65,894)    579,663      511,081     148,932      (156,294)
   Accrued expenses......    428,244     259,602      545,525    (252,435)      534,521
                           ---------  ----------  -----------  ----------   -----------
     Net cash provided by
      (used in) operating
      activities.........    912,106     566,908     (236,892)    111,831         1,856
                           ---------  ----------  -----------  ----------   -----------
Cash flows from investing
 activities:
 (Purchases) maturities
  of short term
  marketable security
  investments, net.......   (604,618)  2,701,323      (35,554)  4,519,658   (15,855,425)
 Purchases of property
  and equipment..........   (132,087)   (322,642)  (1,594,484)   (531,873)   (1,116,120)
 Purchases of Abiomed
  Limited Partnership
  units from limited
  partners (Note 7)......        --     (770,000)         --          --            --
                           ---------  ----------  -----------  ----------   -----------
     Net cash provided by
      (used in) investing
      activities.........   (736,705)  1,608,681   (1,630,038)  3,987,785   (16,971,545)
                           ---------  ----------  -----------  ----------   -----------
Cash flows from financing
 activities:
 Registration fees and
  costs in connection
  with exchange of common
  stock for amounts due
  to Abiomed Limited
  Partnership............    (51,573)        --           --          --            --
 Proceeds from private
  placement of Common
  Stock, net.............        --          --           --          --     15,965,069
 Proceeds from exercise
  of stock options and
  stock purchase plan....     10,205     148,652      545,294     266,401        99,349
                           ---------  ----------  -----------  ----------   -----------
     Net cash (used in)
      provided by
      financing
      activities.........    (41,368)    148,652      545,294     266,401    16,064,418
                           ---------  ----------  -----------  ----------   -----------
Net increase (decrease)
 in cash and cash
 equivalents, excluding
 investments.............    134,033   2,324,241   (1,321,636)  4,366,017      (905,271)
Cash and cash
 equivalents, excluding
 investments, at
 beginning of period.....    480,058     614,091    2,938,332   2,938,332     1,616,696
                           ---------  ----------  -----------  ----------   -----------
Cash and cash
 equivalents, excluding
 investments, at end of
 period..................  $ 614,091  $2,938,332  $ 1,616,696  $7,304,349   $   711,425
                           =========  ==========  ===========  ==========   ===========
</TABLE>    
 
  The accompanying notes are an integral part of these consolidated financial
                                  statements.
 
                                      F-6
<PAGE>
 
                        ABIOMED, INC. AND SUBSIDIARIES
 
                  NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
               
            MARCH 31, 1997 AND SEPTEMBER 30, 1997 (UNAUDITED)     
 
(1) SUMMARY OF OPERATIONS AND SIGNIFICANT ACCOUNTING POLICIES
   
  ABIOMED, Inc. and subsidiaries (the Company) is engaged primarily in the
research, development and commercialization of medical devices, with a primary
focus on the development of cardiac assist and heart replacement technology.
In particular, the Company markets the BVS-5000, a bi-ventricular temporary
cardiac assist device, from which the majority of the Company's product
revenues have been derived. The accompanying consolidated financial statements
reflect the application of certain significant accounting policies described
below.     
 
 (a) Principles of Consolidation
 
  The accompanying consolidated financial statements include the accounts of
the Company and its wholly owned subsidiaries, and beginning in fiscal 1996,
the accounts of its majority-owned subsidiary Abiomed Limited Partnership. All
significant intercompany accounts and transactions have been eliminated in
consolidation.
 
 (b) Uses of Estimates in the Preparation of Financial Statements
 
  The preparation of financial statements in conformity with generally
accepted accounting principles requires management to make estimates and
assumptions that affect the reported amounts of assets and liabilities and
disclosure of contingent assets and liabilities at the date of the financial
statements, and the reported amounts of revenue and expenses during the
reporting period. Actual results could differ from those estimates.
 
 (c) Interim Financial Statements
   
  The accompanying consolidated financial statements include amounts from
interim periods that are unaudited but, in the opinion of management, include
all adjustments (consisting only of normal, recurring adjustments) necessary
for a fair presentation of results for these interim periods. The results of
operations for the six months ended September 30, 1997 are not necessarily
indicative of results to be expected for the fiscal year ending March 31,
1998.     
 
 (d) Product Revenues
 
  The Company recognizes product revenues at the time products are shipped to
the customers. Service revenues, which are not material, are recognized over
the periods of the contracts. In fiscal 1995, 1996 and 1997, 13%, 9% and 7%,
respectively, of product revenues were from customers located outside of the
United States. No customer accounted for greater than 10% of product revenues
during fiscal 1995, 1996 or 1997.
   
  During the year ended March 31, 1997 and the six months ended September 30,
1997, the Company recognized $580,000 and $870,000, respectively, of product
revenues related to sales-type lease transactions. The terms of these
noncancellable leases are for one to three years. As of September 30, 1997,
the long-term portion of these lease payments, approximately $490,000, is
included in other assets and the current portion, approximately $350,000, is
included in accounts receivable.     
 
 (e) Contract Revenues
   
  In fiscal 1995, 1996 and 1997, the majority of the Company's research and
development contract revenues were generated from contracts and grants with
various government agencies. Each of these contracts and grants provide for
revenues on a cost-plus-fixed-fee basis. The Company recognizes revenue under
its government contracts and grants as work is performed, provided that the
government has appropriated sufficient funds for the work. The Company retains
rights to all technological discoveries and products resulting from these
efforts. Costs associated with these contracts and grants are recorded in the
accompanying consolidated financial statements as part of research and
development expenses and totaled approximately $1,718,000, $2,457,000,
$3,232,000, $1,396,000 and $3,410,000 for fiscal 1995, 1996 and 1997, and for
the six months ended September 30, 1996 and 1997, respectively.     
 
                                      F-7
<PAGE>
 
                        ABIOMED, INC. AND SUBSIDIARIES
 
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(CONTINUED)
               
            MARCH 31, 1997 AND SEPTEMBER 30, 1997 (UNAUDITED)     
 
 
 (f) Inventories
 
  Inventories include raw materials, work-in-process and finished goods, are
priced at the lower of cost (first-in, first-out) or market and consist of the
following:
 
<TABLE>   
<CAPTION>
                                                   MARCH 31,
                                             --------------------- SEPTEMBER 30,
                                                1996       1997        1997
                                             ---------- ---------- -------------
                                                                    (unaudited)
   <S>                                       <C>        <C>        <C>
   Raw materials............................ $  799,548 $  896,433  $  919,677
   Work-in-process..........................    428,287    373,383     360,025
   Finished goods...........................    425,677    550,967     567,922
                                             ---------- ----------  ----------
                                             $1,653,512 $1,820,783  $1,847,624
                                             ========== ==========  ==========
</TABLE>    
 
  Finished goods and work-in-process inventories consist of direct material,
labor and overhead.
 
 (g) Depreciation and Amortization
 
  The Company provides for depreciation and amortization by charges to
operations in amounts that allocate the cost of depreciable assets over their
estimated useful lives as follows:
 
<TABLE>
<CAPTION>
                                                                      ESTIMATED
     CLASSIFICATION                          METHOD                  USEFUL LIFE
     --------------                          ------                 -------------
   <S>                       <C>                                    <C>
   Machinery and equip-
    ment...................  Sum-of-the-year's digits/Straight-line    3- 5 Years
   Furniture and fixtures..  Sum-of-the-year's digits/Straight-line    5-10 Years
   Leasehold improvements..  Straight-line                          Life of lease
</TABLE>
 
 (h) Net Income (Loss) per Common and Common Equivalent Share
 
  Net income per common and common equivalent share is computed by dividing
net income by the weighted average number of common and common equivalent
shares outstanding during the period using the treasury stock method. Net loss
per share is computed by dividing the net loss by the weighted average number
of common shares outstanding during the period excluding the effect of stock
options outstanding.
 
 (i) Cash and Cash Equivalents
 
  The Company classifies any marketable security with an original maturity
date of 90 days or less at the time of purchase as a cash equivalent.
 
 (j) Investments
 
  The Company classifies any security, including marketable securities, with
an original maturity of greater than 90 days as investments and classifies
investments with a maturity of greater than one year from the balance sheet
date as long-term investments.
 
  Under Statement of Financial Accounting Standards (SFAS) No. 115, Accounting
for Certain Investments in Debt and Equity Securities, investments that the
Company has the positive intent and ability to hold to maturity are reported
at amortized cost and classified as held-to-maturity. The Company has
classified all investments at March 31, 1996 and 1997 as held-to-maturity. The
amortized cost and market value of short-term investments were approximately
$7,709,000 and $7,545,000 at March 31, 1996 and $7,745,000 and $7,689,000 at
March 31, 1997, respectively. At March 31, 1997, these short-term investments
consisted of government grade securities.
 
                                      F-8
<PAGE>
 
                        ABIOMED, INC. AND SUBSIDIARIES
 
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(CONTINUED)
               
            MARCH 31, 1997 AND SEPTEMBER 30, 1997 (UNAUDITED)     
 
 
 (k) Disclosures about Fair Value of Financial Instruments
 
  As of March 31, 1996 and 1997 the Company's financial instruments were
comprised of cash and cash equivalents, accounts receivable, accounts payable
and short term investments, the carrying amounts of which approximated fair
market value.
 
 (l) Recent Accounting Pronouncements
 
  For fiscal 1997, under SFAS No. 121 Accounting for the Impairment of Long-
lived Assets and for Long-lived Assets to be Disposed of, the Company is
required to review impairment of long-lived assets and certain intangibles
whenever events indicate that the carrying amount of the assets may not be
recoverable. The adoption of this statement did not have a material impact on
the Company's results of operations.
 
  On March 3, 1997, the Financial Accounting Standards Board (FASB) issued
SFAS No. 128, Earnings Per Share, superseding Accounting Principles Board
(APB) Opinion No. 15. SFAS No. 128 establishes standards for the computation
and presentation of earnings per share (EPS) and applies to entities with
publicly held common stock or potential common stock. This statement is
effective for fiscal years ending after December 15, 1997 and requires
restatement of all prior-period EPS data presented. The statement is not
expected to have a material impact on the Company's EPS presentation.
 
(2) CAPITAL STOCK
 
  Each share of Common Stock has a voting right of one vote per share. During
fiscal 1996 and 1997 respectively, 612,000 and 1,428,000 shares of Class A
Common Stock, representing all of the remaining shares of Class A Common
Stock, were converted to Common Stock. As of August 1997, Class A Common Stock
is no longer authorized.
   
  On July 15, 1997, the Company completed a private placement of 1,242,710
shares of its Common Stock. Proceeds to the Company from the private
placement, net of approximately $145,000 in direct transaction related
expenses, totaled approximately $15,965,000.     
 
  The Company has authorized 1,000,000 shares of Class B Preferred Stock, $.01
par value, of which the designation, rights and privileges can be set by the
Board of Directors. No share of Class B Preferred Stock has been issued or is
outstanding.
 
  On August 13, 1997, the Company declared a dividend of one Preferred Share
Purchase Right (the "Right") for each outstanding share of Common Stock to its
stockholders of record at August 28, 1997. Each right entitles the registered
holder to purchase from the Company one one-thousandth of a share of Series A
Junior Participating Preferred Stock with a par value of $0.01 per share, at a
price of $90.00 per one one-thousandth of a share, subject to adjustment.
 
  In accordance with the terms set forth in the Rights Agreement, the Rights
are not exercisable until the occurrence of certain events, as defined. In
addition, the registered holders of the Rights will have no rights as a Common
stockholder of the Company until the Rights are exercised. The terms of the
Rights may be amended by the Board of Directors. The Rights will expire on
August 13, 2007.
 
                                      F-9
<PAGE>
 
                        ABIOMED, INC. AND SUBSIDIARIES
 
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(CONTINUED)
               
            MARCH 31, 1997 AND SEPTEMBER 30, 1997 (UNAUDITED)     
 
 
(3) LINE OF CREDIT WITH A BANK
   
  The Company has an unsecured demand line of credit under which it can borrow
up to $3,000,000 from a bank at the bank's prime rate. The Company is required
to maintain a compensating balance of $100,000 plus 5% of any amounts
outstanding under the arrangement. There were no borrowings under the
company's line of credit at March 31, 1996 and 1997 and September 30, 1997.
The Company has renewed this line of credit in each of the past three years.
The current line of credit expires in September 1998.     
 
(4) INCOME TAXES
 
  The Company accounts for income taxes in accordance with the provisions of
SFAS No. 109, Accounting for Income Taxes. The asset and liability approach
used under SFAS No. 109 requires a recognition of deferred tax assets and
liabilities for the expected future tax consequences of temporary differences
between the carrying amounts and the tax bases of other assets and
liabilities.
 
  At March 31, 1997 the Company had available net operating loss carryforwards
of approximately $21,241,000. The Company also had available, at March 31,
1997, approximately $766,000 of tax credits to reduce future federal income
taxes, if any. The net operating loss and tax credit carryforwards expire
through 2010. These carryforwards are subject to review by the Internal
Revenue Service and may be subject to limitation in any given year under
certain conditions.
 
  During 1997, the Company utilized a portion of its net operating loss
carryforward to reduce its current year taxable income. The Company has placed
a valuation allowance of approximately $11,330,000 as of March 31, 1997
against its otherwise recognizable net deferred tax asset due to the
uncertainty surrounding the timing of the realization of the tax benefits.
 
  The deferred tax asset as of March 31, 1996 and 1997 consisted of the
following:
 
<TABLE>
<CAPTION>
                                                            MARCH 31,
                                                    --------------------------
                                                        1996          1997
                                                    ------------  ------------
   <S>                                              <C>           <C>
   Purchase of technology (Note 7)................. $  1,573,000  $  1,353,000
   Net operating loss and tax credit
    carryforwards..................................    9,082,000     9,262,000
   Other, net......................................      549,000       715,000
                                                    ------------  ------------
                                                      11,204,000    11,330,000
   Less--Valuation allowance.......................  (11,204,000)  (11,330,000)
                                                    ------------  ------------
                                                    $        --   $        --
                                                    ============  ============
</TABLE>
 
(5) COMMITMENTS
 
  (a) The Company leases its facilities and certain equipment under various
operating lease agreements with terms through fiscal 2001. Total rent expense
under these leases, included in the accompanying consolidated statements of
operations, was approximately $262,000, $233,000 and $324,000 for fiscal 1995,
1996 and 1997, respectively.
 
                                     F-10
<PAGE>
 
                        ABIOMED, INC. AND SUBSIDIARIES
 
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(CONTINUED)
               
            MARCH 31, 1997 AND SEPTEMBER 30, 1997 (UNAUDITED)     
 
  Future minimum lease payments under these agreements are as follows:
 
<TABLE>
<CAPTION>
     YEARS ENDED MARCH 31,                                               AMOUNT
     ---------------------                                              --------
     <S>                                                                <C>
       1998............................................................ $307,000
       1999............................................................  247,000
       2000............................................................  120,000
       2001............................................................   31,000
                                                                        --------
                                                                        $705,000
                                                                        ========
</TABLE>
 
  (b) The Company maintains various insurance coverages. Most policies renew
on a fiscal year basis while several policies have been secured for a three-
year period. Future insurance obligations under these insurance policies, over
a three-year period, are approximately $540,000.
 
(6) STOCK OPTIONS PLANS
 
  All stock options granted by the Company under the plans described below
were granted at the fair value of the stock at the date of grant. Outstanding
stock options, if not exercised, expire 10 years from the date of grant.
 
  The 1992 Combination Stock Option Plan (the Combination Plan) as amended,
approved by the Company's stockholders, combined and restated the Company's
then outstanding Incentive Stock Option Plan and Nonqualified Plan. The
options generally become exercisable ratably over five years. All of the
options granted under the Combination Plan during the three years ended March
31, 1997 were to employees.
 
  In addition, the Company has a nonqualified stock option plan for
nonemployee directors (the Directors' Plan). The Directors' Plan, as adopted
in July 1989 and amended, with shareholder approval, granted options to
purchase 12,500 shares of the Company's Common Stock to each of the Company's
then elected outside directors and provides for grants of options to purchase
12,500 shares of the Company's Common Stock to any newly elected eligible
director. Thereafter, each eligible director will be granted a new option to
purchase 12,500 shares of Common Stock on July 1 of each successive fifth
year. These options vest over a five-year period at the rate of 2,500 shares
per year, commencing on June 30 of the year following the date of grant.
 
                                     F-11
<PAGE>
 
                        ABIOMED, INC. AND SUBSIDIARIES
 
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(CONTINUED)
               
            MARCH 31, 1997 AND SEPTEMBER 30, 1997 (UNAUDITED)     
 
 
  The following table summarizes stock option activity under these plans:
 
<TABLE>   
<CAPTION>
                                 COMBINATION PLAN                   DIRECTORS' PLAN
                         ---------------------------------- ---------------------------------
                                                  WEIGHTED                          WEIGHTED
                          NUMBER                   AVERAGE  NUMBER                   AVERAGE
                            OF                      PRICE     OF                      PRICE
                         OPTIONS   EXERCISE PRICE PER SHARE OPTIONS  EXERCISE PRICE PER SHARE
                         --------  -------------- --------- -------  -------------- ---------
<S>                      <C>       <C>            <C>       <C>      <C>            <C>
Options outstanding,
 March 31, 1994.........  410,830  $ 0.55-$13.50   $ 8.47    95,000  $ 7.00-$13.88   $10.72
 Options granted........   17,000     5.63- 6.50     6.19       --             --       --
 Options exercised......   (1,100)          5.75     5.75       --             --       --
 Options canceled.......  (31,500)   5.75- 13.50     8.48       --             --       --
                         --------  -------------   ------   -------  -------------   ------
Options outstanding,
 March 31, 1995.........  395,230     0.55-13.50     8.38    95,000     7.00-13.88   $10.72
 Options granted........  219,000     6.25-11.00    10.23    12,500          11.00    11.00
 Options exercised......  (16,925)    5.75- 8.50     7.34    (2,500)          7.00     7.00
 Options canceled.......  (19,140)    5.75-13.50     9.90   (15,000)   11.00-11.13    11.02
                         --------  -------------   ------   -------  -------------   ------
Options outstanding,
 March 31, 1996.........  578,165     0.55-13.50   $ 9.09    90,000     7.00-13.88    10.81
 Option granted.........  234,235    11.00-13.50    12.53       --             --       --
 Options exercised......  (59,112)    0.55-13.50     8.65       --             --       --
 Options canceled.......  (55,413)    5.75-13.50    11.45       --             --       --
                         --------  -------------   ------   -------  -------------   ------
Options outstanding,
 March 31, 1997.........  697,875  $ 5.63-$13.50   $10.29    90,000  $ 7.00-$13.88   $10.81
 Option granted.........  159,750    10.00-12.15    11.52    50,000          14.00    14.00
 Options exercised...... (12,015)      5.63-8.00     6.96       --             --       --
 Options canceled....... (21,200)     5.63-10.63     9.11       --             --       --
                         --------  -------------   ------   -------  -------------   ------
Options outstanding,
 September 30, 1997.....  824,410  $ 5.63-$13.50   $10.53   140,000  $ 7.00-$14.00   $10.81
                         ========                           =======
Options exercisable:
 March 31, 1997.........  179,415  $ 5.63-$13.50    $8.96    70,000  $ 7.00-$13.88   $10.76
                         ========                           =======
 September 30, 1997.....  182,500  $ 5.63-$13.50    $9.02    82,500  $ 7.00-$14.00   $10.76
                         ========                           =======
Shares available for
 Future issuance,
 March 31, 1997.........  459,032                           107,500
                         ========                           =======
 September 30, 1997.....  320,482                            57,500
                         ========                           =======
</TABLE>    
   
  The Company has an Employee Stock Purchase Plan (the Purchase Plan), as
amended. Under the Purchase Plan, all employees (including officers and
directors) of the Company who have completed six months of employment are
eligible to purchase the Company's Common Stock at an exercise price equal to
85% of the fair market value of the Common Stock. The Company has reserved
100,000 shares of Common Stock for issuance under the Purchase Plan, of which
89,138 shares are available for future issuance as of March 31, 1997. During
the years ended March 31, 1996 and 1997, and the six months ended September
30, 1997, 777 shares, 1,116 shares and 1,549 shares, respectively, of Common
Stock were sold pursuant to the Purchase Plan.     
 
                                     F-12
<PAGE>
 
                        ABIOMED, INC. AND SUBSIDIARIES
 
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(CONTINUED)
               
            MARCH 31, 1997 AND SEPTEMBER 30, 1997 (UNAUDITED)     
 
 
  In October 1995, FASB issued SFAS No. 123, Accounting for Stock-Based
Compensation. SFAS No. 123 requires the measurement of the fair value of stock
options, including stock purchase plans, or warrants granted to employees to
be included in the statement of operations or disclosed in the notes to
financial statements. The Company has determined that it will continue to
account for stock-based compensation for employees under APB Opinion No. 25
and elect the disclosure-only alternative under SFAS No 123. The Company has
computed the pro forma disclosures required under SFAS No. 123 for options
granted in fiscal 1996 and 1997 using the Black-Scholes option pricing model
prescribed by SFAS No. 123. The weighted average information and assumptions
used for 1996 and 1997 are as follows:
 
<TABLE>
<CAPTION>
                                                                1996     1997
                                                               -------  -------
     <S>                                                       <C>      <C>
     Risk-free interest rate..................................    6.75%    6.75%
     Expected dividend yield..................................     --       --
     Expected life............................................ 5 years  5 years
     Expected volatility......................................      30%      33%
</TABLE>
 
  The Black-Scholes option-pricing model was developed for use in estimating
the fair value of traded options, which have no vesting restrictions and are
fully transferable. In addition, option-pricing models require the input of
highly subjective assumptions including expected stock price volatility.
Because the Company's employee stock options have characteristics
significantly different from those of traded options, and because changes in
the subjective input assumptions can materially affect the fair value
estimate, in management's opinion, the existing models do not necessarily
provide a reliable single measure of the fair value of its employee stock
options.
 
  The total fair value of the options granted during fiscal 1996 and 1997 was
computed as approximately $431,000 and $598,000, respectively. Of these
amounts approximately $108,000 and $257,000 would be charged to operations for
the years ended March 31, 1996 and 1997 respectively. The remaining amount,
approximately $664,000, would be amortized over the remaining vesting periods.
Similarly, the total fair value of stock sold under this Purchase Plan was
computed as approximately $4,000 and $3,000 during fiscal 1996 and 1997. The
resulting pro forma compensation expense may not be representative of the
amount to be expected in future years as pro forma compensation expense may
vary based upon the number of options granted and shares purchased.
 
  The pro forma net income and pro forma net income per common share presented
below have been computed assuming no tax benefit. The effect of a tax benefit
has not been considered since a substantial portion of the stock options
granted are incentive stock options and the Company does not anticipate a
future deduction associated with the exercise of these stock options.
 
  The pro forma effect of SFAS No. 123 for the years ended March 31, 1996 and
1997 is as follows:
 
<TABLE>
<CAPTION>
                                            1996                  1997
                                    --------------------- ---------------------
                                    AS REPORTED PRO FORMA AS REPORTED PRO FORMA
                                    ----------- --------- ----------- ---------
   <S>                              <C>         <C>       <C>         <C>
   Net income.....................   $491,124   $379,124   $735,264   $475,264
   Pro forma net income per common
    and common equivalent share...   $  0 .07   $  0 .05   $  0 .10   $  0 .07
</TABLE>
 
(7) ROYALTY OBLIGATION
 
  Commencing April 1, 1995 and ending August 3, 2000, the Company owes a
royalty to certain third parties equal in aggregate to approximately 2.1% of
certain revenues derived from the BVS 5000 and certain
 
                                     F-13
<PAGE>
 
                        ABIOMED, INC. AND SUBSIDIARIES
 
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(CONTINUED)
               
            MARCH 31, 1997 AND SEPTEMBER 30, 1997 (UNAUDITED)     
   
other technology. This royalty is subject to certain maximum revenue amounts
and to certain adjustments, as defined, in the event that the Company sells
the underlying technology. For the years ended March 31, 1996 and 1997, and
the six months ended September 30, 1997 the amount of this royalty, net of
certain reimbursed expenses, was approximately $160,000, $216,000 and $174,000
respectively. These amounts are reflected as part of the cost of product sales
in the accompanying consolidated financial statements.     
 
  This royalty is paid to the third parties through Abiomed Limited
Partnership which, at present, is inactive except with respect to the
distribution of such royalties. During fiscal 1996, the Company paid $770,000
to reduce its royalty obligation to 2.1%, as described above. This one-time
payment capitalized by the Company, is being amortized on a straight-line
basis over the estimated useful life of the asset (5 years) and, net of
accumulated amortization, is classified as a long-term other asset in the
accompanying consolidated financial statements.
 
(8) EMPLOYEE DEFERRED COMPENSATION PROFIT-SHARING PLAN AND TRUST
 
  The Company has an Employee Deferred Compensation Profit-sharing Plan and
Trust (the 401(k) Plan) that covers all employees over 20 years of age who
have completed at least six months of service with the Company. Contributions
by the Company are determined by the Company's Board of Directors and totaled
approximately $36,000, $80,000 and $59,000 for the fiscal years ended March
31, 1995, 1996 and 1997, respectively.
 
(9) ACCRUED EXPENSES
 
  Accrued expenses consist of the following:
 
<TABLE>   
<CAPTION>
                                                  MARCH 31,
                                            --------------------- SEPTEMBER 30,
                                               1996       1997        1997
                                            ---------- ---------- -------------
                                                                   (unaudited)
   <S>                                      <C>        <C>        <C>
   Salaries and benefits................... $  703,478 $  700,570  $1,227,718
   Legal and audit.........................     72,436     76,914     103,106
   Customer advances.......................     56,067    287,882      67,340
   Sales taxes.............................    214,521    172,836     221,023
   Warranty................................     72,662    227,093     187,472
   Other...................................    367,817    567,211     760,368
                                            ---------- ----------  ----------
                                            $1,486,981 $2,032,506  $2,567,027
                                            ========== ==========  ==========
</TABLE>    
 
                                     F-14
<PAGE>
 
 
[DRAWING OF A TAH IMPLANTED          THE COMPANY'S TOTAL ARTIFICIAL HEART IS
IN A WOMAN]                          A CLASS III DEVICE UNDER DEVELOPMENT
                                     AND HAS NOT BEEN APPROVED FOR SALE IN ANY
                                     COUNTRY. THE COMPANY DOES NOT INTEND TO
                                     APPLY FOR REGULATORY APPROVAL TO MARKET
                                     THIS DEVICE FOR SEVERAL YEARS, IF EVER,
                                     AND WILL BE REQUIRED TO SUCCESSFULLY
                                     COMPLETE CLINICAL TRIALS TO DEMONSTRATE
                                     ITS SAFETY AND EFFICACY PRIOR TO FILING
                                     FOR REGULATORY APPROVAL. SEE "RISK
                                     FACTORS."
   
[ILLUSTRATION OF THE IMPLANTABLE             ILLUSTRATION OF THE IMPLANTABLE
COMPONENTS]                                  COMPONENTS OF THE ABIOMED TAH, A
                                             BATTERY-POWERED TOTALLY
                                             IMPLANTABLE ARTIFICIAL HEART BEING
                                             DEVELOPED AS A PERMANENT
                                             REPLACEMENT DEVICE TO ASSUME THE
                                             FULL PUMPING FUNCTION OF BOTH THE
                                             LEFT AND RIGHT VENTRICLES OF THE
                                             HEART.     

                                            
DEVELOPMENTAL MODEL TAH WITH THE             [PHOTOGRAPH OF TAH SYSTEM.
IMPLANTABLE COMPONENTS: THE THORACIC         COMPONENTS OF TAH SYSTEM ARE
UNIT, THE INTERNAL RECHARGEABLE              IDENTIFIED WITH CAPTIONS]  
BATTERY, THE INTERNAL ELECTRONICS 
PACKAGE AND THE INTERNAL COMPONENT 
OF THE ENERGY TRANSMISSION SYSTEM.     

<PAGE>
 
 
 
 
                         [ABIOMED LOGO APPEARS HERE]
 
 
 
<PAGE>
 
                                    PART II
 
                    INFORMATION NOT REQUIRED IN PROSPECTUS
 
ITEM 14. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION
 
<TABLE>
<S>                                                                     <C>
SEC Registration Fee................................................... $14,323
NASD Filing Fee........................................................  30,500
Nasdaq National Market Listing Fee.....................................  17,500
Transfer Agent and Registrant Fees.....................................   2,500*
Accounting Fees and Expenses...........................................  50,000*
Legal Fees and Expenses................................................ 175,000*
Printing and Engraving ................................................  60,000*
Miscellaneous..........................................................  50,177*
                                                                        -------
  TOTAL................................................................ 400,000*
                                                                        =======
</TABLE>
- --------
* Estimated
 
ITEM 15. INDEMNIFICATION OF DIRECTORS AND OFFICERS
 
  The Company's Certificate of Incorporation provides that, to the fullest
extent permitted by Delaware law, no director of the Company shall be
personally liable to the Company or its stockholders for monetary damages for
breach of fiduciary duty as a director, notwithstanding any other provision of
law. However, a director shall be liable to the extent required by law (i) for
any breach of the director's duty of loyalty to the Company or its
stockholders, (ii) for acts or omissions not in good faith or which involve
intentional misconduct or a knowing violation of law, (iii) in respect of
certain unlawful dividend payments or stock redemptions or repurchases, or
(iv) for any transaction from which the director derived an improper personal
benefit.
 
  The Company entered into indemnification agreements with each of its
directors and anticipates that it will enter into similar agreements with any
future director. Generally, these agreements attempt to provide the maximum
protection permitted by Delaware law with respect to indemnification. The
indemnification agreements provide that the Company will pay certain amounts
incurred by a director in connection with any civil or criminal action or
proceeding, specifically including actions by or in the name of the Company
(derivative suits) where the individual's involvement is by reason of the fact
that he is or was a director or officer. For directors, such amounts include,
to the maximum extent permitted by law, attorney's fees, judgments, civil or
criminal fines, settlement amounts and other expenses customarily incurred in
connection with legal proceedings. Under the indemnification agreements, a
director will not receive indemnification if the director is found not to have
acted in good faith and in a manner he reasonably believed to be in or not
opposed to the best interests of the Company. The Company has also entered
into similar agreements with certain of the Company's officers and top
management personnel who are not also directors. The indemnification
agreements with officers are slightly more restrictive. Generally, the
indemnification agreements attempt to provide the maximum protection permitted
by Delaware law with respect to indemnification of directors and officers.
 
  The effect of these provisions would be to permit such indemnification by
the Company for liabilities arising under the Securities Act of 1933, as
amended.
 
  Reference is hereby made to Section 8 of the Underwriting Agreement among
the Company, the Selling Stockholders and the Underwriters, filed as Exhibit
1.1 to this Registration Statement, for a description of indemnification
arrangements among the Company, the Selling Stockholders and the Underwriters.
 
  Reference is hereby made to Section 2 of the Selling Stockholder Agreement
among the Company and the Selling Stockholders, filed as Exhibit 99.1 to this
Registration Statement, for a description of indemnification arrangements
among the Company and the Selling Stockholders.
 
                                     II-1
<PAGE>
 
ITEM 16. EXHIBITS
 
<TABLE>   
<CAPTION>
 EXHIBIT
 NUMBER
 -------  
 <C>     <S> 
  1.1    Form of Underwriting Agreement***
  3.1    Restated Certificate of Incorporation of the Company**
  3.2    Restated Bylaws of the Company--Filed as Exhibit 3(b) to the
         Company's Annual Report on Form 10-K for the fiscal year ended
         March 31, 1991*
         Certificate of Designations of Series A Junior Participating
  3.3    Preferred Stock**
  4.1    Specimen Certificate of Common Stock--Filed as Exhibit 4.1 to
         Registration Statement No. 33-14861 on Form S-1*
  4.2    Description of Capital Stock (contained in the Restated
         Certificate of Incorporation of the Company filed as Exhibit 3.1
         and in the Certificate of Designations of Series A Junior
         Participating Preferred Stock filed as Exhibit 3.3)**
  4.3    Rights Agreement between the Registrant and BankBoston, N.A., as
         Rights Agent dated as of August 13, 1997 (including Form of
         Right Certificate attached thereto as Exhibit A)--Filed as
         Exhibit 4 to the Registrant's Current Report on Form 8-K, dated
         August 13, 1997*
  5.1    Legal Opinion of Brown, Rudnick, Freed & Gesmer**
 23.1    Consent of Arthur Andersen LLP***
         Consent of Brown, Rudnick, Freed & Gesmer (included in Exhibit
 23.2    5.1)**
 24.1    Power of Attorney (previously filed, except for Power of
         Attorney of one director which is filed herewith)** ***
 99.1    Form of Selling Stockholder Agreement***
 99.2    Common Stock Purchase Agreement between the Company and Genzyme
         Corporation**
 99.3    Common Stock Purchase Agreements between the Company and certain
         directors**
</TABLE>    
 
- --------
  * Not filed herewith. In accordance with Rule 411 promulgated pursuant to
    the Securities Act of 1933, as amended, reference is made to the documents
    previously filed with the Commission, which are incorporated by reference
    herein.
   
 ** Previously filed.     
   
*** Filed herewith.     
 
ITEM 17. UNDERTAKINGS
 
  (a) Insofar as indemnification for liabilities arising under the Securities
Act of 1933 may be permitted to directors, officers and controlling persons of
the Registrant pursuant to the Registrants By-Laws, or otherwise, the
Registrant has been advised that in the opinion of the Securities and Exchange
Commission such indemnification is against public policy as expressed in the
Act and is, therefore, unenforceable. In the event
 
                                     II-2
<PAGE>
 
that a claim for indemnification against such liabilities (other than the
payment by the Registrant of expenses incurred or paid by a director, officer
or controlling person of the Registrant in the successful defense of any
action, suit or proceeding) is asserted by such director, officer or
controlling person in connection with the securities being registered, the
Registrant will, unless in the opinion of its counsel the matter has been
settled by controlling precedent, submit to a court of appropriate
jurisdiction the question whether such indemnification by it is against public
policy as expressed in the Act and will be governed by the final adjudication
of such issue.
 
  (b) The undersigned Registrant hereby further undertakes that:
 
    (1) For purposes of determining any liability under the Securities Act of
  1933, each filing of the Registrant's annual report pursuant to Section
  13(a) or Section 15(d) of the Securities Exchange Act of 1934 (and, where
  applicable, each filing of an employee benefit plan's annual report
  pursuant to Section 15(d) of the Securities Exchange Act of 1934) that is
  incorporated by reference in the registration statement shall be deemed to
  be a new registration statement relating to the securities offered therein,
  and the offering of such securities at that time shall be deemed to be
  initial bona fide offering thereof.
 
    (2) For purposes of determining any liability under the Securities Act of
  1933, the information omitted from the form of prospectus filed as part of
  this registration statement in reliance upon Rule 430A and contained in a
  form of prospectus filed by the Registrant pursuant to Rule 424(b)(1) or
  (4) or 497(h) under the Securities Act shall be deemed to be part of this
  registration statement as of the time it was declared effective.
 
    (3) For the purpose of determining any liability under the Securities Act
  of 1933, each post-effective amendment that contains a form of prospectus
  shall be deemed to be a new registration statement relating to the
  securities offered therein, and the offering of such securities at that
  time shall be deemed to be the initial bona fide offering thereof.
 
                                     II-3
<PAGE>
 
                                  SIGNATURES
   
  PURSUANT TO THE REQUIREMENTS OF THE SECURITIES ACT OF 1933, THE REGISTRANT
CERTIFIES THAT IT HAS DULY CAUSED THIS AMENDMENT NO. 1 TO THE REGISTRATION
STATEMENT TO BE SIGNED ON ITS BEHALF BY THE UNDERSIGNED, THEREUNTO DULY
AUTHORIZED, IN THE CITY OF BOSTON, COMMONWEALTH OF MASSACHUSETTS, ON OCTOBER
10, 1997.     
 
                                          ABIOMED, Inc.
                                                 
                                              /s/ Dr. David M. Lederman 
                                          By: _________________________________
                                            DR. DAVID M. LEDERMANPRESIDENT AND
                                                  CHIEF EXECUTIVE OFFICER
                                                                             
       
   
  PURSUANT TO THE REQUIREMENTS OF THE SECURITIES ACT OF 1933, THIS AMENDMENT
NO. 1 TO THIS REGISTRATION STATEMENT HAS BEEN SIGNED BY THE FOLLOWING PERSONS
IN THE CAPACITIES AND ON THE DATES INDICATED.     
 
              SIGNATURE                        TITLE                 DATE
 
                                        Chief Executive    
     /s/ David M. Lederman              Officer, President     October 10, 1997
- -------------------------------------   and Director                      
          DAVID M. LEDERMAN             (Principal
                                        Executive Officer)
 
                                        Chief Financial   
       /s/ John F. Thero                Officer, Vice          October 10, 1997
- -------------------------------------   President--Finance                 
            JOHN F. THERO               and Treasurer
                                        (Principal Financial
                                        and Accounting
                                        Officer)
                                               
       
       
                                       Director       
               *                                               October 10, 1997
- -------------------------------------                                    
      DESMOND H. O'CONNELL, JR.
 
                                       Director      
               *                                               October 10, 1997
- -------------------------------------                                    
           JOHN F. O'BRIEN
 
                                       Director   
               *                                               October 10, 1997
- -------------------------------------                                    
          HENRI A. TERMEER
 
                                       Director  
               *                                               October 10, 1997
- -------------------------------------                                    
          W. GERALD AUSTEN
 
                                       Director     
               *                                               October 10, 1997
- -------------------------------------                                    
            PAUL FIREMAN           
   
     /s/ David M. Lederman 
*By: ___________________________ 
     DAVID M. LEDERMANATTORNEY-IN-FACT
                    
                                     II-4
<PAGE>
 
                                 EXHIBIT INDEX
 
<TABLE>   
<CAPTION>
 EXHIBIT
 NUMBER  DESCRIPTION
 ------- -----------
 <C>     <S>
  1.1    Form of Underwriting Agreement***
  3.1    Restated Certificate of Incorporation of the Company**
  3.2    Restated Bylaws of the Company--Filed as Exhibit 3(b) to the Company's
         Annual Report on Form 10-K for the fiscal year ended March 31, 1991*
         Certificate of Designations of Series A Junior Participating Preferred
  3.3    Stock**
  4.1    Specimen Certificate of Common Stock--Filed as Exhibit 4.1 to
         Registration Statement No. 33-14861 on Form S-1*
  4.2    Description of Capital Stock (contained in the Restated Certificate of
         Incorporation of the Company filed as Exhibit 3.1 and in the
         Certificate of Designations of Series A Junior Participating Preferred
         Stock filed as Exhibit 3.3)**
  4.3    Rights Agreement between the Registrant and BankBoston, N.A., as
         Rights Agent dated as of August 13, 1997 (including Form of Right
         Certificate attached thereto as Exhibit A)--Filed as Exhibit 4 to the
         Registrant's Current Report on Form 8-K, dated August 13, 1997*
  5.1    Legal Opinion of Brown, Rudnick, Freed & Gesmer**
 23.1    Consent of Arthur Andersen LLP***
 23.2    Consent of Brown, Rudnick, Freed & Gesmer (included in Exhibit 5.1)**
 24.1    Power of Attorney (previously filed, except for Power of Attorney of
         one director of which is filed herewith)** ***
 99.1    Form of Selling Stockholder Agreement***
 99.2    Common Stock Purchase Agreement between the Company and Genzyme
         Corporation**
 99.3    Common Stock Purchase Agreements between the Company and certain
         directors**
</TABLE>    
 
- --------
  * Not filed herewith. In accordance with Rule 411 promulgated pursuant to
    the Securities Act of 1933, as amended, reference is made to the documents
    previously filed with the Commission, which are incorporated by reference
    herein.
   
 ** Previously filed.     
   
*** Filed herewith.     

<PAGE>
 
                                                                     Exhibit 1.1



                              2,400,000 Shares/1/

                                 ABIOMED, INC.

                                 COMMON STOCK


                            UNDERWRITING AGREEMENT
                            ----------------------

                                                              ____________, 1997


BANCAMERICA ROBERTSON STEPHENS
UBS SECURITIES LLC
 As Representatives of the several Underwriters
c/o BancAmerica Robertson Stephens
555 California Street
Suite 2600
San Francisco, California  94104

Ladies/Gentlemen:

     ABIOMED, Inc., a Delaware corporation (the "Company"), and certain
stockholders of the Company named in Schedule B hereto (herein collectively
                                     ----------                            
called the "Selling Stockholders"), address you as the Representatives of each
of the persons, firms and corporations listed in Schedule A hereto (herein
                                                 ----------               
collectively called the "Underwriters") and hereby confirm their respective
agreements with the several Underwriters as follows:

     1.  Description of Shares. The Company proposes to issue and sell
         ---------------------                                         
2,250,000 shares of its authorized and unissued Common Stock, par value $0.01
per share, to the several Underwriters.  The Selling Stockholders, acting
severally and not jointly, propose to sell an aggregate of 150,000 shares of the
Company's authorized and outstanding Common Stock, par value $0.01 per share, to
the several Underwriters.  The 2,250,000 shares of Common Stock, par value $0.01
per share, of the Company to be sold by the Company are hereinafter called the
"Company Shares" and the 150,000 shares of Common Stock, par value $0.01 per
share, to be sold by the Selling Stockholders are hereinafter called the
"Selling Stockholder Shares."  The Company Shares and the Selling Stockholder
Shares are hereinafter collectively referred to as the "Firm Shares."  The
Company also proposes to grant to the Underwriters an option to purchase
up to 360,000 additional shares of the

- -----------------------------
/1/ Plus an option to purchase up to 360,000 additional shares from the Company 
to cover over-allotments, if any.
<PAGE>
 
Company's Common Stock, par value $0.01 per share (the "Option Shares"), as
provided in Section 7 hereof. As used in this Agreement, the term "Shares" shall
include the Firm Shares and the Option Shares. All shares of Common Stock, par
value $0.01 per share, of the Company to be outstanding after giving effect to
the sales contemplated hereby, including the Shares, are hereinafter referred to
as "Common Stock."

     2.  Representations, Warranties and Agreements of the Company and the
         -----------------------------------------------------------------
Selling Stockholders.
- -------------------- 
 
     I.  The Company represents and warrants to and agrees with each Underwriter
and each Selling Stockholder that:
 
     (a) A registration statement on Form S-3 (File No. 333-36657) with respect
to the Shares, including a prospectus subject to completion, has been prepared
by the Company in conformity with the requirements of the Securities Act of
1933, as amended (the "Act"), and the applicable rules and regulations (the
"Rules and Regulations") of the Securities and Exchange Commission (the
"Commission") under the Act and has been filed with the Commission; such
amendments to such registration statement, such amended prospectuses subject to
completion and such abbreviated registration statements pursuant to Rule 462(b)
of the Rules and Regulations as may have been required prior to the date hereof
have been similarly prepared and filed with the Commission; and the Company will
file such additional amendments to such registration statement, such amended
prospectuses subject to completion and such abbreviated registration statements
pursuant to Rule 462(b) of the Rules and Regulations as may hereafter be
required.  Copies of such registration statement and amendments, of each related
prospectus subject to completion (the "Preliminary Prospectuses"), including all
documents incorporated by reference therein, and of any abbreviated registration
statement pursuant to Rule 462(b) of the Rules and Regulations have been
delivered to you.  The Company and the transactions contemplated by this
Agreement meet the requirements for using Form S-3 under the Act.
 
     If the registration statement relating to the Shares has been declared
effective under the Act by the Commission, the Company will prepare and promptly
file with the Commission the information omitted from the registration statement
pursuant to Rule 430A(a) or, if BancAmerica Robertson Stephens, on behalf of the
several Underwriters, shall agree to the utilization of Rule 434 of the Rules
and Regulations, the information required to be included in any term sheet filed
pursuant to Rule 434(b) or (c), as applicable, of the Rules and Regulations
pursuant to subparagraph (1), (4) or (7) of Rule 424(b) of the Rules and
Regulations or as part of a post-effective amendment to the registration
statement (including a final form of prospectus).  If the registration statement
relating to the Shares has not been declared effective under the Act by the
Commission, the Company will prepare and promptly file an amendment to the
registration statement, including a final form of prospectus, or, if BancAmerica
Robertson Stephens, on behalf of the several Underwriters, shall agree to the
utilization of Rule 434 of the Rules and Regulations, the information required
to be included in any term sheet filed pursuant to Rule 434(b) or (c), as
applicable, of the Rules and Regulations.  The term "Registration Statement" as
used in this Agreement shall mean such registration statement, including
financial statements, schedules and exhibits, in the form in which it became or
becomes, as the case may be, effective (including, if the

                                      -2-
<PAGE>
 
Company omitted information from the registration statement pursuant to Rule
430A(a) or files a term sheet pursuant to Rule 434 of the Rules and Regulations,
the information deemed to be a part of the registration statement at the time it
became effective pursuant to Rule 430A(b) or Rule 434(d) of the Rules and
Regulations) and, in the event of any amendment thereto or the filing of any
abbreviated registration statement pursuant to Rule 462(b) of the Rules and
Regulations relating thereto after the effective date of such registration
statement, shall also mean (from and after the effectiveness of such amendment
or the filing of such abbreviated registration statement) such registration
statement as so amended, together with any such abbreviated registration
statement pursuant to Rule 462(b) of the Rules and Regulations. The term
"Prospectus" as used in this Agreement shall mean the prospectus relating to the
Shares as included in such Registration Statement at the time it becomes
effective (including, if the Company omitted information from the Registration
Statement pursuant to Rule 430A(a) of the Rules and Regulations, the information
deemed to be a part of the Registration Statement at the time it became
effective pursuant to Rule 430A(b) of the Rules and Regulations);
provided, however, that if in reliance on Rule 434 of the Rules and Regulations
- --------  -------                                                              
and with the consent of BancAmerica Robertson Stephens, on behalf of the several
Underwriters, the Company shall have provided to the Underwriters a term sheet
pursuant to Rule 434(b) or (c), as applicable, prior to the time that a
confirmation is sent or given for purposes of Section 2(10)(a) of the Act, the
term "Prospectus" shall mean the "prospectus subject to completion" (as defined
in Rule 434(g) of the Rules and Regulations) last provided to the Underwriters
by the Company and circulated by the Underwriters to all prospective purchasers
of the Shares (including the information deemed to be a part of the Registration
Statement at the time it became effective pursuant to Rule 434(d) of the Rules
and Regulations).  Notwithstanding the foregoing, if any revised prospectus
shall be provided to the Underwriters by the Company for use in connection with
the offering of the Shares that differs from the prospectus referred to in the
immediately preceding sentence (whether or not such revised prospectus is
required to be filed with the Commission pursuant to Rule 424(b) of the Rules
and Regulations), the term "Prospectus" shall refer to such revised prospectus
from and after the time it is first provided to the Underwriters for such use.
If in reliance on Rule 434 of the Rules and Regulations and with the consent of
BancAmerica Robertson Stephens, on behalf of the several Underwriters, the
Company shall have provided to the Underwriters a term sheet pursuant to Rule
434(b) or (c), as applicable, prior to the time that a confirmation is sent or
given for purposes of Section 2(10)(a) of the Act, the Prospectus and the term
sheet, together, will not be materially different from the prospectus in the
Registration Statement.  Any reference to the Registration Statement or the
Prospectus shall be deemed to refer to and include the documents incorporated by
reference therein pursuant to Item 12 of Form S-3 under the Act, as of the date
of the Registration Statement or the Prospectus, as the case may be, and any
reference to any amendment or supplement to the Registration Statement or the
Prospectus shall be deemed to refer to and include any documents filed after
such date under the Securities Exchange Act of 1934, as amended (the "Exchange
Act"), which, upon filing, are incorporated by reference therein, as required by
paragraph (b) of Item 12 of Form S-3.  As used in this Agreement, the term
"Incorporated Documents" means the documents which at the time are incorporated
by reference in the Registration Statement, the Prospectus or any amendment or
supplement thereto.
 
     (b) The Commission has not issued any order preventing or suspending the
use of any Preliminary Prospectus or instituted proceedings for that purpose,
and each such Preliminary Prospectus has conformed in all material respects to
the requirements of the Act and

                                      -3-
<PAGE>
 
the Rules and Regulations and, as of its date, has not included any untrue
statement of a material fact or omitted to state a material fact necessary to
make the statements therein, in the light of the circumstances under which they
were made, not misleading; and at the time the Registration Statement became or
becomes, as the case may be, effective and at all times subsequent thereto up to
and on the Closing Date (as hereinafter defined) and up to and on any later date
on which Option Shares are to be purchased, (i) the Registration Statement and
the Prospectus, and any amendments or supplements thereto, contained and will
contain all material information required to be included therein by the Act and
the Rules and Regulations and will in all material respects conform to the
requirements of the Act and the Rules and Regulations, (ii) the Registration
Statement, and any amendments or supplements thereto, did not and will not
include any untrue statement of a material fact or omit to state a material fact
required to be stated therein or necessary to make the statements therein not
misleading, and (iii) the Prospectus, and any amendments or supplements thereto,
did not and will not include any untrue statement of a material fact or omit to
state a material fact necessary to make the statements therein, in the light of
the circumstances under which they were made, not misleading; provided, however,
                                                              --------  -------
that none of the representations and warranties contained in this subparagraph
(b) shall apply to information contained in or omitted from the Registration
Statement or Prospectus, or any amendment or supplement thereto, in reliance
upon, and in conformity with, written information relating to any Underwriter
furnished to the Company by such Underwriter specifically for use in the
preparation thereof.
 
     The Incorporated Documents heretofore filed, when they were filed (or, if
any amendment with respect to any such document was filed, when such amendment
was filed), conformed in all material respects with the requirements of the
Exchange Act and the rules and regulations of the Commission thereunder; any
further Incorporated Documents so filed will, when they are filed, conform in
all material respects with the requirements of the Exchange Act and the rules
and regulations of the Commission thereunder; no such document when it was filed
(or, if an amendment with respect to any such document was filed, when such
amendment was filed), contained any untrue statement of a material fact or
omitted to state a material fact required to be stated therein or necessary to
make the statements therein not misleading; and no such further amendment will
contain any untrue statement of a material fact or omit to state a material fact
required to be stated therein or necessary to make the statements therein not
misleading.
 
     (c)  Each of the Company and its subsidiaries has been duly incorporated
and is validly existing as a corporation in good standing under the laws of the
jurisdiction of its incorporation with full power and authority (corporate and
other) to own, lease and operate its properties and conduct its business as
described in the Prospectus; the Company owns all of the outstanding capital
stock of its subsidiaries free and clear of any pledge, lien, security interest,
encumbrance, claim or equitable interest; each of the Company and its
subsidiaries is duly qualified to do business as a foreign corporation and is in
good standing in each jurisdiction in which the ownership or leasing of its
properties or the conduct of its business requires such qualification, except
where the failure to be so qualified or be in good standing would not have a
material adverse effect on the condition (financial or otherwise), earnings,
operations, business or business prospects of the Company and its subsidiaries
considered as one enterprise; no proceeding has been instituted in any such
jurisdiction, revoking, limiting or curtailing, or seeking to revoke, limit or
curtail, such power and authority or qualification; each of the Company and its
subsidiaries is in possession of

                                      -4-
<PAGE>
 
and operating in compliance with all authorizations, licenses, approvals,
certificates, consents, orders and permits from state, federal and other
domestic and foreign regulatory authorities, including, without limitation, the
United States Food and Drug Administration (the "FDA"), which are material to
the conduct of its business, all of which are valid and in full force and
effect; neither the Company nor any of its subsidiaries is in violation of its
respective charter or bylaws or in default in the performance or observance of
any material obligation, agreement, covenant or condition contained in any
material bond, debenture, note or other evidence of indebtedness, or in any
material lease, contract, indenture, mortgage, deed of trust, loan agreement,
joint venture or other agreement or instrument to which the Company or any of
its subsidiaries is a party or by which it or any of its subsidiaries or their
respective properties may be bound; neither the Company nor any of its
subsidiaries is in material violation of any law, order, rule, regulation, writ,
injunction, judgment or decree of any court, government or governmental agency
or body, domestic or foreign, having jurisdiction over the Company or any of its
subsidiaries or over their respective properties of which it has knowledge;
neither the Company nor any of its subsidiaries is in material violation of the
Food, Drug and Cosmetic Act, as amended, or any of the rules and regulations of
the FDA, including the FDA's Quality System Regulations, or of the rules and
regulations of any other federal, state or foreign regulatory body or agency;
there is not any pending or, to the best of the Company's knowledge, threatened
FDA enforcement action against the Company or any of its subsidiaries; and to
the best of the Company's knowledge there is not any pending or threatened
investigation by the FDA of the Company or any of its subsidiaries or any of
their products. The Company does not own or control, directly or indirectly, any
corporation, association or other entity other than ABIOMED Cardiovascular,
Inc., ABIODENT, Inc., ABIOMED R&D, Inc., ABD Holding Company, Inc., Abiomed
Research & Development, Inc. and Abiomed Limited Partnership (collectively, the
"subsidiaries").

     (d) The Company has full legal right, power and authority to enter into
this Agreement and the Custody Agreement (as hereinafter defined) and perform
the transactions contemplated hereby and thereby. Each of this Agreement and the
Custody Agreement has been duly authorized, executed and delivered by the
Company and is a valid and binding agreement on the part of the Company,
enforceable in accordance with its terms, except as rights to indemnification
hereunder may be limited by applicable law and except as the enforcement hereof
and thereof may be limited by applicable bankruptcy, insolvency, reorganization,
moratorium or other similar laws relating to or affecting creditors' rights
generally or by general equitable principles; the performance of this Agreement
and the Custody Agreement, and the consummation of the transactions herein and
therein contemplated, will not result in a material breach or violation of any
of the terms and provisions of, or constitute a default under, (i) any bond,
debenture, note or other evidence of indebtedness, or any lease, contract,
indenture, mortgage, deed of trust, loan agreement, joint venture or other
agreement or instrument to which the Company or any of its subsidiaries is a
party or by which it or any of its subsidiaries or their respective properties
may be bound, (ii) the charter or bylaws of the Company or any of its
subsidiaries, or (iii) any law, order, rule, regulation, writ, injunction,
judgment or decree of any court, government or governmental agency or body,
domestic or foreign, having jurisdiction over the Company or any of its
subsidiaries or over their respective properties. No consent, approval,
authorization or order of or qualification with any court, government or
governmental agency or body, domestic or foreign, having jurisdiction over the
Company or any of its subsidiaries or over their respective properties is

                                      -5-
<PAGE>
 
required for the execution and delivery of this Agreement and the Custody
Agreement and the consummation by the Company or any of its subsidiaries of the
transactions herein or therein contemplated, except such as may be required by
the National Association of Securities Dealers, Inc. (the "NASD") with respect
to the listing of the additional shares of Common Stock to be offered hereby on
The Nasdaq National Market or as may be required under the Act or under state or
other securities or Blue Sky laws, all of which requirements have been satisfied
in all material respects.
 
     (e)  There is not any pending or, to the best of the Company's knowledge,
threatened action, suit, claim or proceeding against the Company, any of its
subsidiaries or any of their respective officers or any of their respective
properties, assets or rights before any court, government or governmental agency
or body, domestic or foreign, having jurisdiction over the Company or any of its
subsidiaries or over their respective officers or properties or otherwise which
(i) might result in any material adverse change in the condition (financial or
otherwise), earnings, operations, business or business prospects of the Company
and its subsidiaries considered as one enterprise or might materially and
adversely affect their properties, assets or rights, (ii) might prevent
consummation of the transactions contemplated hereby or (iii) is required to be
disclosed in the Registration Statement or Prospectus and is not so disclosed;
and there are no agreements, contracts, leases or documents of the Company or
any of its subsidiaries of a character required to be described or referred to
in the Registration Statement or Prospectus or any Incorporated Document or to
be filed as an exhibit to the Registration Statement or any Incorporated
Document by the Act or the Rules and Regulations or by the Exchange Act or the
rules and regulations of the Commission thereunder which have not been
accurately described in all material respects in the Registration Statement or
Prospectus or any Incorporated Document or filed as exhibits to the Registration
Statement or any Incorporated Document.
 
     (f) All outstanding shares of capital stock of the Company (including the
Selling Stockholder Shares) have been duly authorized and validly issued and are
fully paid and nonassessable, have been issued in compliance with all federal
and state securities laws, were not issued in violation of or subject to any
preemptive rights or other rights to subscribe for or purchase securities, and
the authorized and outstanding capital stock of the Company is as set forth in
the Prospectus under the caption "Capitalization" and conforms in all material
respects to the statements relating thereto contained in the Registration
Statement and the Prospectus and any Incorporated Document (and such statements
correctly state the substance of the instruments defining the capitalization of
the Company); the Company Shares and the Option Shares have been duly authorized
for issuance and sale to the Underwriters pursuant to this Agreement and, when
issued and delivered by the Company against payment therefor in accordance with
the terms of this Agreement, will be duly and validly issued and fully paid and
nonassessable, and will be sold free and clear of any pledge, lien, security
interest, encumbrance, claim or equitable interest; and no preemptive right, co-
sale right, registration right, right of first refusal or other similar right of
shareholders exists with respect to any of the Company Shares or Option Shares
or the issuance and sale thereof other than those that have been expressly
waived prior to the date hereof and those that will automatically expire upon
and will not apply to the consummation of the transactions contemplated on the
Closing Date. No further approval or authorization of any stockholder, the Board
of Directors of the Company or others is required for the issuance and sale or
transfer of the

                                      -6-
<PAGE>
 
Shares except as may be required under the Act, under state or other securities
or Blue Sky laws or with respect to the listing of the Shares on The Nasdaq
National Market. All issued and outstanding shares of capital stock or
partnership interests, as applicable, of each subsidiary of the Company have
been duly authorized and validly issued and are fully paid and nonassessable,
and were not issued in violation of or subject to any preemptive right, or other
rights to subscribe for or purchase shares or partnership interests, as
applicable, and are owned by the Company free and clear of any pledge, lien,
security interest, encumbrance, claim or equitable interest, except for Abiomed
Limited Partnership of which the Company owns 61.7% of the outstanding
partnership interests. Except as disclosed in the Prospectus and the financial
statements of the Company, and the related notes thereto, included in the
Prospectus, neither the Company nor any subsidiary has outstanding any options
to purchase, or any preemptive rights or other rights to subscribe for or to
purchase, any securities or obligations convertible into, or any contracts or
commitments to issue or sell, shares of its capital stock or partnership
interests, or any such options, rights, convertible securities or obligations.
The description of the Company's stock option, stock bonus and other stock plans
or arrangements, and the options or other rights granted and exercised
thereunder, set forth or incorporated by reference in the Prospectus accurately
and fairly presents the information required to be shown with respect to such
plans, arrangements, options and rights in all material respects.
 
     (g) Arthur Andersen LLP, which has examined the consolidated balance sheets
of the Company, together with the related schedules and notes, as of March 31,
1996 and 1997 and the related consolidated statements of operations,
stockholders' investment and cash flows for each of the three (3) years in the
period ended March 31, 1997 filed with the Commission as a part of the
Registration Statement, which are included in the Prospectus, are independent
accountants within the meaning of the Act and the Rules and Regulations; the
audited consolidated financial statements of the Company, together with the
related schedules and notes, and the unaudited consolidated financial
information, forming part of the Registration Statement and Prospectus, fairly
present the financial position and the results of operations of the Company and
its subsidiaries at the respective dates and for the respective periods to which
they apply; and all audited consolidated financial statements of the Company,
together with the related schedules and notes, and the unaudited consolidated
financial information, filed with the Commission as part of or incorporated by
reference into the Registration Statement, have been prepared in accordance with
generally accepted accounting principles consistently applied throughout the
periods involved except as may be otherwise stated therein.  The selected and
summary financial and statistical data included or incorporated by reference in
the Registration Statement present fairly the information shown therein and have
been compiled on a basis consistent with the audited financial statements
presented therein.  No other financial statements or schedules are required to
be included or incorporated by reference in the Registration Statement.

     (h) Subsequent to the respective dates as of which information is given in
the Registration Statement and Prospectus, there has not been (i) any material
adverse change in the condition (financial or otherwise), earnings, operations,
business or business prospects of the Company and its subsidiaries considered as
one enterprise, (ii) any transaction that is material to the Company and its
subsidiaries considered as one enterprise, except transactions entered into in
the ordinary course of business, (iii) any obligation, direct or contingent,
that is material to the

                                      -7-
<PAGE>
 
Company and its subsidiaries considered as one enterprise, incurred by the
Company or its subsidiaries, except obligations incurred in the ordinary course
of business, (iv) any change in the capital stock, partnership interests or
outstanding indebtedness of the Company or any of its subsidiaries that is
material to the Company and its subsidiaries considered as one enterprise, (v)
any dividend or distribution of any kind declared, paid or made on the capital
stock of the Company or any of its subsidiaries, or (vi) any loss or damage
(whether or not insured) to the property of the Company or any of its
subsidiaries which has been sustained or will have been sustained which has a
material adverse effect on the condition (financial or otherwise), earnings,
operations, business or business prospects of the Company and its subsidiaries
considered as one enterprise.
 
     (i) Except as set forth in the Registration Statement and Prospectus and
any Incorporated Document, (i) each of the Company and its subsidiaries has good
and marketable title to all properties and assets described in the Registration
Statement and Prospectus and any Incorporated Document as owned by it, free and
clear of any pledge, lien, security interest, encumbrance, claim or equitable
interest, other than such as would not have a material adverse effect on the
condition (financial or otherwise), earnings, operations, business or business
prospects of the Company and its subsidiaries considered as one enterprise, (ii)
the agreements to which the Company or any of its subsidiaries is a party
described in the Registration Statement and Prospectus and any Incorporated
Document are valid agreements, enforceable by the Company and its subsidiaries
(as applicable), except as the enforcement thereof may be limited by applicable
bankruptcy, insolvency, reorganization, moratorium or other similar laws
relating to or affecting creditors' rights generally or by general equitable
principles and, to the best of the Company's knowledge, the other contracting
party or parties thereto are not in material breach or material default under
any of such agreements, and (iii) each of the Company and its subsidiaries has
valid and enforceable leases for all properties described in the Registration
Statement and Prospectus and any Incorporated Document as leased by it, except
as the enforcement thereof may be limited by applicable bankruptcy, insolvency,
reorganization, moratorium or other similar laws relating to or affecting
creditors' rights generally or by general equitable principles.  Except as set
forth in the Registration Statement and Prospectus and any Incorporated
Document, the Company owns or leases all such properties as are necessary to its
operations as now conducted or as proposed to be conducted.
 
     (j) The Company and its subsidiaries have timely filed all necessary
federal, state and foreign income and franchise tax returns and have paid all
taxes shown thereon as due, and there is no tax deficiency that has been or, to
the best of the Company's knowledge, might be asserted against the Company or
any of its subsidiaries that might have a material adverse effect on the
condition (financial or otherwise), earnings, operations, business or business
prospects of the Company and its subsidiaries considered as one enterprise; and
all tax liabilities are adequately provided for on the books of the Company and
its subsidiaries.
 
     (k) The Company and its subsidiaries maintain insurance with insurers of
recognized financial responsibility of the types and in the amounts generally
deemed adequate for their respective businesses and consistent with insurance
coverage maintained by similar companies in similar businesses, including, but
not limited to, product liability insurance, insurance

                                      -8-
<PAGE>
 
covering real and personal property owned or leased by the Company or its
subsidiaries against theft, damage, destruction, acts of vandalism, and
insurance covering all other risks customarily insured against, all of which
insurance is in full force and effect; neither the Company nor any such
subsidiary has been refused any insurance coverage sought or applied for; and
neither the Company nor any such subsidiary has any reason to believe that it
will not be able to renew its existing insurance coverage as and when such
coverage expires or to obtain similar coverage from similar insurers as may be
necessary to continue its business at a cost that would not materially and
adversely affect the condition (financial or otherwise), earnings, operations,
business or business prospects of the Company and its subsidiaries considered as
one enterprise.
 
     (l) To the best of the Company's knowledge, no labor disturbance by the
employees of the Company or any of its subsidiaries exists or is imminent; and
the Company is not aware of any existing or imminent labor disturbance by the
employees of any of its principal suppliers, subcontractors, dealers or
distributors that might be expected to result in a material adverse change in
the condition (financial or otherwise), earnings, operations, business or
business prospects of the Company and its subsidiaries considered as one
enterprise.  No collective bargaining agreement exists with any of the Company's
or any of its subsidiaries' employees and, to the best of the Company's
knowledge, no such agreement is imminent.
 
     (m) Each of the Company and its subsidiaries owns or possesses adequate
rights to use all patents, patent rights, inventions, trade secrets, know-how,
trademarks, service marks, trade names and copyrights (collectively,
"Intellectual Property Rights") which are necessary to conduct its business as
described in the Registration Statement and Prospectus and any Incorporated
Document; the Company has not received any notice of, and has no knowledge of,
any infringement of or conflict with asserted rights of the Company by others
with respect to any Intellectual Property Rights; and the Company has not
received any notice of, and has no knowledge of, any infringement of or conflict
with asserted rights of others with respect to any Intellectual Property Rights
which, singly or in the aggregate, if the subject of an unfavorable decision,
ruling or finding, might have a material adverse effect on the condition
(financial or otherwise), earnings, operations, business or business prospects
of the Company and its subsidiaries considered as one enterprise; and to the
knowledge of the Company, none of the patents owned by the Company or any of its
subsidiaries are unenforceable or invalid.  The Company has duly and properly
filed or caused to be filed with the United States Patent and Trademark Office
(the "PTO") and applicable foreign and international patent authorities all
patent applications described or referred to in the Prospectus, and believes it
has complied with the PTO's duty of candor and disclosure for each of the United
States patent applications described or referred to in the Prospectus; the
Company is unaware of any facts which would preclude the grant of a patent from
each of the patent applications described or referred to in the
Prospectus; and the Company has no knowledge of any facts which would preclude
it from having clear title to its patent applications described or referred to
in the Prospectus.
 
     (n) The Common Stock is registered pursuant to Section 12(g) of the
Exchange Act and is listed on The Nasdaq National Market, and the Company has
taken no action designed to, or likely to have the effect of, terminating the
registration of the Common Stock under the Exchange Act or delisting the Common
Stock from The Nasdaq National Market, nor has the

                                      -9-
<PAGE>
 
Company received any notification that the Commission or the NASD is
contemplating terminating such registration or listing.
 
     (o) The Company has been advised concerning the Investment Company Act of
1940, as amended (the "1940 Act"), and the rules and regulations thereunder, and
has in the past conducted, and intends in the future to conduct, its affairs in
such a manner as to ensure that it will not become an "investment company" or a
company "controlled" by an "investment company" within the meaning of the 1940
Act and such rules and regulations.
 
     (p) The Company has not distributed and will not distribute prior to the
later of (i) the Closing Date, or any date on which Option Shares are to be
purchased, as the case may be, and (ii) completion of the distribution of the
Shares, any offering material in connection with the offering and sale of the
Shares other than any Preliminary Prospectuses, the Prospectus, the Registration
Statement and other materials, if any, permitted by the Act.
 
     (q) Neither the Company nor any of its subsidiaries has at any time during
the last five (5) years (i) made any unlawful contribution to any candidate for
foreign office or failed to disclose fully any contribution in violation of law,
or (ii) made any payment to any federal or state governmental officer or
official, or other person charged with similar public or quasi-public duties,
other than payments required or permitted by the laws of the United States or
any jurisdiction thereof.
 
     (r) The Company has not taken and will not take, directly or indirectly,
any action designed to or that might reasonably be expected to cause or result
in stabilization or manipulation of the price of the Common Stock to facilitate
the sale or resale of the Shares.
 
     (s) Each executive officer and director of the Company, each Selling
Stockholder and Genzyme Corporation have agreed in writing that such person will
not, directly or indirectly, sell, offer, contract to sell, pledge, grant any
option to purchase or otherwise dispose of (collectively, a "Disposition") any
shares of Common Stock or any securities convertible into or exchangeable for,
or any rights to purchase or acquire, Common Stock (the "Securities") held by
such person, acquired by such person after the date hereof or which may be
deemed to be beneficially owned by such person pursuant to the Rules and
Regulations, for a period commencing on the date such agreement was executed and
ending 90 days after the effective date of the Registration Statement (the
"Lock-Up Period"), otherwise than (i) as a bona fide gift or gifts, provided the
donee or donees thereof agree in writing to be bound by this restriction, (ii)
as a distribution to partners or shareholders of such person, provided that the
distributees thereof agree in writing to be bound by the terms of this
restriction, or (iii) with the prior written consent of BancAmerica Robertson
Stephens. The foregoing restriction has been expressly agreed to preclude the
holder of the Securities from engaging in any hedging or other transaction which
is designed to or reasonably expected to lead to or result in a Disposition of
Securities during the Lock-up Period, even if such Securities would be disposed
of by someone other than such holder. Such prohibited hedging or other
transactions would include, without limitation, any short sale (whether or not
against the box) or any purchase, sale or grant of any right (including, without
limitation, any put or call option) with respect to any Securities or with
respect to any security (other than a broad-based

                                      -10-
<PAGE>
 
market basket or index) that includes, relates to or derives any significant
part of its value from Securities. Furthermore, such person has also agreed and
consented to the entry of stop transfer instructions with the Company's transfer
agent against the transfer of the Securities held by such person except in
compliance with this restriction. The Company has provided to counsel for the
Underwriters a complete and accurate list of all securityholders of the Company
and the number and type of securities held by each securityholder. The Company
has provided to counsel for the Underwriters true, accurate and complete copies
of all of the agreements, if any, pursuant to which its officers, directors and
shareholders have agreed to such or similar restrictions (the "Lock-up
Agreements") presently in effect or effected hereby. The Company hereby
represents and warrants that it will not release any of its officers, directors
or other shareholders from any Lock-up Agreements currently existing or
hereafter effected without the prior written consent of BancAmerica Robertson
Stephens.
 
     (t) Except as set forth in the Registration Statement and Prospectus and
any Incorporated Document, (i) the Company and each of its subsidiaries is in
compliance with all rules, laws and regulations relating to the use, treatment,
storage and disposal of toxic substances and protection of health or the
environment ("Environmental Laws") which are applicable to its business, (ii)
neither the Company nor any of its subsidiaries has received any notice from any
governmental authority or third party of an asserted claim under Environmental
Laws, which claim is required to be disclosed in the Registration Statement, the
Prospectus or any Incorporated Document, (iii) neither the Company nor any of
its subsidiaries will be required to make future material capital expenditures
to comply with Environmental Laws and (iv) no property which is owned, leased or
occupied by the Company or any subsidiary has been designated as a Superfund
site pursuant to the Comprehensive Response, Compensation, and Liability Act of
1980, as amended (42 U.S.C. (S) 9601, et seq.), or otherwise designated as a
                                      -- ----                               
contaminated site under applicable state or local law.
 
     (u) The Company and each of its subsidiaries maintain a system of internal
accounting controls sufficient to provide reasonable assurances that (i)
transactions are executed in accordance with management's general or specific
authorizations, (ii) transactions are recorded as necessary to permit
preparation of financial statements in conformity with generally accepted
accounting principles and to maintain accountability for assets, (iii) access to
assets is permitted only in accordance with management's general or specific
authorization, and (iv) the recorded accountability for assets is compared with
existing assets at reasonable intervals and appropriate action is taken with
respect to any differences.

     (v) There are no outstanding loans, advances (except normal advances for
business expenses in the ordinary course of business) or guarantees of
indebtedness by the Company to or for the benefit of any of the officers or
directors of the Company or any of the members of the families of any of them,
except as disclosed in the Registration Statement and the Prospectus and any
Incorporated Document.
 
     (w) The Company has complied with all provisions of Section 517.075,
Florida Statutes relating to doing business with the Government of Cuba or with
any person or affiliate located in Cuba.

                                      -11-
<PAGE>
 
     II.  Each Selling Stockholder severally and not jointly, represents and
warrants to and agrees with each Underwriter and the Company that:
 
     (a) Such Selling Stockholder now has and, on the Closing Date, will have
valid marketable title to the Shares to be sold by such Selling Stockholder,
free and clear of any pledge, lien, security interest, encumbrance, claim or
equitable interest other than pursuant to this Agreement; and upon delivery of
such Shares hereunder and payment of the purchase price as herein contemplated,
each of the Underwriters will obtain valid marketable title to the Shares
purchased by it from such Selling Stockholder, free and clear of any pledge,
lien, security interest pertaining to such Selling Stockholder or such Selling
Stockholder's property, encumbrance, claim or equitable interest, including any
liability for estate or inheritance taxes, or any liability to or claims of any
creditor, devisee, legatee or beneficiary of such Selling Stockholder.
 
     (b) Such Selling Stockholder has duly authorized (if applicable), executed
and delivered, in the form heretofore furnished to the Representatives, an
irrevocable Power of Attorney (the "Power of Attorney") appointing David M.
Lederman and John F. Thero as attorneys-in-fact (collectively, the "Attorneys"
and individually, an "Attorney") and a Letter of Transmittal and Custodian
Agreement (the "Custody Agreement") with the Company, as custodian (the
"Custodian"); each of the Power of Attorney and the Custody Agreement
constitutes a valid and binding agreement on the part of such Selling
Stockholder, enforceable in accordance with its terms, except as the enforcement
thereof may be limited by applicable bankruptcy, insolvency, reorganization,
moratorium or other similar laws relating to or affecting creditors' rights
generally or by general equitable principles; and each of such Selling
Stockholder's Attorneys, acting alone, is authorized to execute and deliver this
Agreement and the certificate referred to in Section 6(i) hereof on behalf of
such Selling Stockholder, to determine the purchase price to be paid by the
several Underwriters to such Selling Stockholder as provided in Section 3
hereof, to authorize the delivery of the Selling Stockholder Shares pursuant to
the terms of this Agreement and to duly endorse (in blank or otherwise) the
certificate or certificates representing such Shares or a stock power or powers
with respect thereto, to accept payment therefor, and otherwise to act on behalf
of such Selling Stockholder in connection with this Agreement.
 
     (c) All consents, approvals, authorizations and orders required for the
execution and delivery by such Selling Stockholder of the Power of Attorney and
the Custody Agreement, the execution and delivery by or on behalf of such
Selling Stockholder of this Agreement and the sale and delivery of the Selling
Stockholder Shares under this Agreement (other than, at the time of the
execution hereof (if the Registration Statement has not yet been declared
effective by the Commission), the issuance of the order of the Commission
declaring the Registration Statement effective and such consents, approvals,
authorizations or orders as may be necessary under state or other securities or
Blue Sky laws) have been obtained and are in full force and effect; such Selling
Stockholder, if other than a natural person, has been duly organized and is
validly existing in good standing under the laws of the jurisdiction of its
organization as the type of entity that it purports to be; and such Selling
Stockholder has full legal right, power and authority to enter into and perform
its obligations under this Agreement, such Power of Attorney and such

                                      -12-
<PAGE>
 
Custody Agreement, and to sell, assign, transfer and deliver the Shares to be
sold by such Selling Stockholder under this Agreement.
 
     (d) Such Selling Stockholder will not, during the Lock-up Period, effect
the Disposition of any Securities, otherwise than (i) as a bona fide gift or
gifts, provided the donee or donees thereof agree in writing to be bound by this
restriction, (ii) as a distribution to partners or shareholders of such Selling
Stockholder, provided that the distributees thereof agree in writing to be bound
by the terms of this restriction, or (iii) with the prior written consent of
BancAmerica Robertson Stephens.  The foregoing restriction is expressly agreed
to preclude the holder of the Securities from engaging in any hedging or other
transaction which is designed to or reasonably expected to lead to or result in
a Disposition of Securities during the Lock-up Period, even if such Securities
would be disposed of by someone other than the Selling Stockholder.  Such
prohibited hedging or other transactions would including, without limitation,
any short sale (whether or not against the box), or any purchase, sale or grant
of any right (including, without limitation, any put or call option) with
respect to any Securities or with respect to any security (other than a broad-
based market basket or index) that includes, relates to or derives any
significant part of its value from Securities.  Such Selling Stockholder also
agrees and consents to the entry of stop transfer instructions with the
Company's transfer agent against the transfer of the securities held by such
Selling Stockholder except in compliance with this restriction.
 
     (e) Certificates in negotiable form for all Shares to be sold by such
Selling Stockholder under this Agreement, together with a stock power or powers
duly endorsed in blank by such Selling Stockholder, have been placed in custody
with the Custodian for the purpose of effecting delivery hereunder.
 
     (f) This Agreement has been duly authorized by each Selling Stockholder
that is not a natural person and has been duly executed and delivered by or on
behalf of each Selling Stockholder and is a valid and binding agreement of each
Selling Stockholder, enforceable in accordance with its terms, except as rights
to indemnification hereunder may be limited by applicable law and except as the
enforcement hereof may be limited by bankruptcy, insolvency, reorganization,
moratorium or other similar laws relating to or affecting creditors' rights
generally or by general equitable principles; and the performance of this
Agreement and the consummation of the transactions herein contemplated will not
result in a breach or violation of any of the terms and provisions of or
constitute a default under any bond, debenture, note or other evidence of
indebtedness, or under any lease, contract, indenture, mortgage, deed of trust,
loan agreement, joint venture or other agreement or instrument to which such
Selling Stockholder is a party or by which such Selling Stockholder, or any
Selling Stockholder Shares hereunder, may be bound or, to the best of such
Selling Stockholders' knowledge, result in any violation of any law, order,
rule, regulation, writ, injunction, judgment or decree of any court, government
or governmental agency or body, domestic or foreign, having jurisdiction over
such Selling Stockholder or over the properties of such Selling Stockholder, or,
if such Selling Stockholder is other than a natural person, result in any
violation of any provisions of the charter, bylaws or other organizational
documents of such Selling Stockholder.

                                      -13-
<PAGE>
 
     (g) Such Selling Stockholder has not taken and will not take, directly or
indirectly, any action designed to or that might reasonably be expected to cause
or result in stabilization or manipulation of the price of the Common Stock to
facilitate the sale or resale of the Shares.
 
     (h) Such Selling Stockholder has not distributed and will not distribute
any prospectus or other offering material in connection with the offering and
sale of the Shares.
 
     (i) All information furnished by or on behalf of such Selling Stockholder
relating to such Selling Stockholder and the Selling Stockholder Shares that is
contained in the representations and warranties of such Selling Stockholder in
such Selling Stockholder's Power of Attorney or set forth in the Registration
Statement or the Prospectus is, and at the time the Registration Statement
became or becomes, as the case may be, effective and at all times subsequent
thereto up to and on the Closing Date was or will be, true, correct and
complete, and does not, and at the time the Registration Statement became or
becomes, as the case may be, effective and at all times subsequent thereto up to
and on the Closing Date will not, contain any untrue statement of a material
fact or omit to state a material fact required to be stated therein or necessary
to make such information not misleading.
 
     (j) Such Selling Stockholder will review the Prospectus and will comply
with all agreements and satisfy all conditions on its part to be complied with
or satisfied pursuant to this Agreement on or prior to the Closing Date and will
advise one of its Attorneys and BancAmerica Robertson Stephens prior to the
Closing Date if any statement to be made on behalf of such Selling Stockholder
in the certificate contemplated by Section 6(i) would be inaccurate if made as
of the Closing Date.
 
     (k) Such Selling Stockholder does not have, or has waived prior to the date
hereof, any preemptive right, co-sale right or right of first refusal or other
similar right to purchase any of the Shares that are to be sold by the Company
or any of the other Selling Stockholders to the Underwriters pursuant to this
Agreement; such Selling Stockholder does not have, or has waived prior to the
date hereof, any registration right or other similar right to participate in the
offering made by the Prospectus, other than such rights of participation as have
been satisfied by the participation of such Selling Stockholder in the
transactions to which this Agreement relates in accordance with the terms of
this Agreement; and such Selling Stockholder does not own any warrants, options
or similar rights to acquire, and does not have any right or arrangement to
acquire, any capital stock, rights, warrants, options or other securities from
the Company, other than those described in the Registration Statement and the
Prospectus and any Incorporated Document.
 
     (l) Such Selling Stockholder is not aware that any of the representations
and warranties of the Company set forth in Section 2.I. above is untrue or
inaccurate.
 
     3.  Purchase, Sale and Delivery of Shares.  On the basis of the
         -------------------------------------                      
representations, warranties and agreements herein contained, but subject to the
terms and conditions herein set forth, the Company and the Selling Stockholders
agree, severally and not jointly, to sell to the

                                      -14-
<PAGE>
 
Underwriters, and each Underwriter agrees, severally and not jointly, to 
purchase from the Company and the Selling Stockholders, respectively, at 
a purchase price of $_____ per share, the respective number of Company 
Shares and Selling Stockholder Shares set forth opposite the names of the
Company and the Selling Stockholders in Schedule B hereto.  The obligation
                                        ----------        
of each Underwriter to the Company and to each Selling Stockholder shall be to
purchase from the Company or such Selling Stockholder that number of Company
Shares or Selling Stockholder Shares, as the case may be, which (as nearly as
practicable, as determined by you) is in the same proportion to the number of
Company Shares or Selling Stockholder Shares, as the case may be, set forth
opposite the name of the Company or such Selling Stockholder in
                                                                             
Schedule B hereto as the number of Company Shares which is set forth opposite
- ----------                                                                   
the name of such Underwriter in Schedule A hereto (subject to adjustment as
                                ----------                                 
provided in Section 10) is to the total number of Firm Shares to be purchased by
all the Underwriters under this Agreement.
 
     The certificates in negotiable form for the Selling Stockholder Shares have
been placed in custody (for delivery under this Agreement) under the Custody
Agreement.  Each Selling Stockholder agrees that the certificates for the
Selling Stockholder Shares of such Selling Stockholder so held in custody are
subject to the interests of the Underwriters hereunder, that the arrangements
made by such Selling Stockholder for such custody, including the Power of
Attorney and the Custody Agreement, are to that extent irrevocable and that the
obligations of such Selling Stockholder hereunder shall not be terminated by the
act of such Selling Stockholder or by operation of law, whether by the death or
incapacity of such Selling Stockholder or the occurrence of any other event,
except as specifically provided herein or in the Custody Agreement.  If any
Selling Stockholder should die or be incapacitated, or if any other such event
should occur, before the delivery of the certificates for the Selling
Stockholder Shares hereunder, the Selling Stockholder Shares to be sold by such
Selling Stockholder shall, except as specifically provided herein or in the
Custody Agreement, be delivered by the Custodian in accordance with the terms
and conditions of this Agreement as if such death, incapacity or other event had
not occurred, regardless of whether the Custodian shall have received notice of
such death or other event.
 
     Delivery of definitive certificates for the Firm Shares to be purchased by
the Underwriters pursuant to this Section 3 shall be made against payment of the
purchase price therefor by the several Underwriters by certified or official
bank check or checks drawn in next-day funds, payable to the order of the
Company with regard to the Shares being purchased from the Company, and to the
order of the Custodian for the respective accounts of the Selling Stockholders
with regard to the Shares being purchased from such Selling Stockholders (and
the Company and such Selling Stockholders agree not to deposit and to cause the
Custodian not to deposit any such check in the bank on which it is drawn, and
not to take any other action with the purpose or effect of receiving immediately
available funds, until the business day following the date of its delivery to
the Company or the Custodian, as the case may be, and, in the event of any
breach of the foregoing, the Company or the Selling Stockholders, as the case
may be, shall reimburse the Underwriters for the interest lost and any other
expenses borne by them by reason of such breach), at the offices of Brown,
Rudnick, Freed & Gesmer, One Financial Center, Boston, MA 02111 (or at such
other place as may be agreed upon among the Representatives and the Company and
the Attorneys), at 7:00 A.M., San Francisco time (a) on the third (3rd) full
business day following the first day that Shares are traded, (b) if this
Agreement is executed and delivered after 1:30 P.M., San Francisco

                                      -15-
<PAGE>
 
time, the fourth (4th) full business day following the day that this Agreement
is executed and delivered or (c) at such other time and date not later than
seven (7) full business days following the first day that Shares are traded as
the Representatives, the Company and the Attorneys may determine (or at such
time and date to which payment and delivery shall have been postponed pursuant
to Section 10 hereof), such time and date of payment and delivery being herein
called the "Closing Date;" provided, however, that if the Company has not made
                           --------  -------
available to the Representatives copies of the Prospectus within the time
provided in Section 4(d) hereof, the Representatives may, in their sole
discretion, postpone the Closing Date until no later than two (2) full business
days following delivery of copies of the Prospectus to the Representatives. The
certificates for the Firm Shares to be so delivered will be made available to
you at such office or such other location including, without limitation, in New
York City, as you may reasonably request for checking at least one (1) full
business day prior to the Closing Date and will be in such names and
denominations as you may request, such request to be made at least two (2) full
business days prior to the Closing Date. If the Representatives so elect,
delivery of the Firm Shares may be made by credit through full fast transfer to
the accounts at The Depository Trust Company designated by the Representatives.
 
     It is understood that you, individually, and not as the Representatives of
the several Underwriters, may (but shall not be obligated to) make payment of
the purchase price on behalf of any Underwriter or Underwriters whose check or
checks shall not have been received by you prior to the Closing Date for the
Firm Shares to be purchased by such Underwriter or Underwriters.  Any such
payment by you shall not relieve any such Underwriter or Underwriters of any of
its or their obligations hereunder.
 
     After the Registration Statement becomes effective, the several
Underwriters intend to make an initial public offering (as such term is
described in Section 11 hereof) of the Firm Shares at an initial public offering
price of $_____ per share.  After the initial public offering, the several
Underwriters may, in their discretion, vary the public offering price.
 
     The information set forth in the last paragraph on the front cover page
(insofar as such information relates to the Underwriters), on the inside front
cover concerning stabilization and passive market making by the Underwriters,
and in the first, second, seventh, eighth, ninth, tenth and eleventh paragraphs
under the caption "Underwriting" in any Preliminary Prospectus and in the
Prospectus constitutes the only information furnished by the Underwriters to the
Company for inclusion in any Preliminary Prospectus, the Prospectus or the
Registration Statement or any Incorporated Document, and you, on behalf of the
respective Underwriters, represent and warrant to the Company and the Selling
Stockholders that the statements made therein do not include any untrue
statement of a material fact or omit to state a material fact required to be
stated therein or necessary to make the statements therein, in the light of the
circumstances under which they were made, not misleading.

                                      -16-
<PAGE>
 
     4.  Further Agreements of the Company.  The Company agrees with the several
         ---------------------------------                                      
Underwriters that:
 
     (a) The Company will use its best efforts to cause the Registration
Statement and any amendment thereof, if not effective at the time and date that
this Agreement is executed and delivered by the parties hereto, to become
effective as promptly as possible; the Company will use its best efforts to
cause any abbreviated registration statement pursuant to Rule 462(b) of the
Rules and Regulations as may be required subsequent to the date the Registration
Statement is declared effective to become effective as promptly as possible; the
Company will notify you, promptly after it shall receive notice thereof, of the
time when the Registration Statement, any subsequent amendment to the
Registration Statement or any abbreviated registration statement has become
effective or any supplement to the Prospectus has been filed; if the Company
omitted information from the Registration Statement at the time it was
originally declared effective in reliance upon Rule 430A(a) of the Rules and
Regulations, the Company will provide evidence satisfactory to you that the
Prospectus contains such information and has been filed, within the time period
prescribed, with the Commission pursuant to subparagraph (1) or (4) of Rule
424(b) of the Rules and Regulations or as part of a post-effective amendment to
such Registration Statement as originally declared effective which is declared
effective by the Commission; if the Company files a term sheet pursuant to Rule
434 of the Rules and Regulations, the Company will provide evidence satisfactory
to you that the Prospectus and term sheet meeting the requirements of Rule
434(b) or (c), as applicable, of the Rules and Regulations, have been filed,
within the time period prescribed, with the Commission pursuant to subparagraph
(7) of Rule 424(b) of the Rules and Regulations; if for any reason the filing of
the final form of Prospectus is required under Rule 424(b)(3) of the Rules and
Regulations, it will provide evidence satisfactory to you that the Prospectus
contains such information and has been filed with the Commission within the time
period prescribed; it will notify you promptly of any request by the Commission
for the amending or supplementing of the Registration Statement or the
Prospectus or for additional information; promptly upon your request, it will
prepare and file with the Commission any amendments or supplements to the
Registration Statement or Prospectus which, in the opinion of Testa, Hurwitz &
Thibeault, LLP as counsel for the several Underwriters ("Underwriters'
Counsel"), may be necessary or advisable in connection with the distribution of
the Shares by the Underwriters; it will promptly prepare and file with the
Commission, and promptly notify you of the filing of, any amendments or
supplements to the Registration Statement or Prospectus which may be necessary
to correct any statements or omissions, if, at any time when a prospectus
relating to the Shares is required to be delivered under the Act, any event
shall have occurred as a result of which the Prospectus or any other prospectus
relating to the Shares as then in effect would include any untrue statement of a
material fact or omit to state a material fact necessary to make the statements
therein, in the light of the circumstances under which they were made, not
misleading; in case any Underwriter is required to deliver a prospectus nine (9)
months or more after the effective date of the Registration Statement in
connection with the sale of the Shares, it will prepare promptly upon request,
but at the expense of such Underwriter, such amendment or amendments to the
Registration Statement and such prospectus or prospectuses as may be necessary
to permit compliance with the requirements of Section 10(a)(3) of the Act; and
it will file no amendment or supplement to the Registration Statement or
Prospectus or the Incorporated Documents, or, prior to the end of the period of
time in which a prospectus relating to the Shares is required to be delivered
under the Act, file any

                                      -17-
<PAGE>
 
document which upon filing becomes an Incorporated Document, which shall not
previously have been submitted to you a reasonable time prior to the proposed
filing thereof or to which you shall reasonably object in writing, subject,
however, to compliance with the Act and the Rules and Regulations, the Exchange
Act and the rules and regulations of the Commission thereunder and the
provisions of this Agreement.
 
     (b) The Company will advise you, promptly after it shall receive notice or
obtain knowledge, of the issuance of any stop order by the Commission suspending
the effectiveness of the Registration Statement or of the initiation or threat
of any proceeding for that purpose; and it will promptly use its best efforts to
prevent the issuance of any stop order or to obtain its withdrawal at the
earliest possible moment if such stop order should be issued.
 
     (c) The Company will use its best efforts to qualify the Shares for
offering and sale under the securities laws of such jurisdictions as you may
designate and to continue such qualifications in effect for so long as may be
required for purposes of the distribution of the Shares, except that the Company
shall not be required in connection therewith or as a condition thereof to
qualify as a foreign corporation or to execute a general consent to service of
process in any jurisdiction in which it is not otherwise required to be so
qualified or to so execute a general consent to service of process.  In each
jurisdiction in which the Shares shall have been qualified as above provided,
the Company will make and file such statements and reports in each year as are
or may be required by the laws of such jurisdiction so as to continue such
qualifications in effect for so long as may be required for purposes of the
distribution of the Shares.
 
     (d) The Company will furnish to you, as soon as available, and, in the case
of the Prospectus and any term sheet or abbreviated term sheet under Rule 434,
in no event later than the first (1st) full business day following the first day
that Shares are traded, copies of the Registration Statement (three of which
will be signed and which will include all exhibits), each Preliminary
Prospectus, the Prospectus and any amendments or supplements to such documents,
including any prospectus prepared to permit compliance with Section 10(a)(3) of
the Act, and the Incorporated Documents (three of which will include all
exhibits), all in such quantities as you may from time to time reasonably
request.  Notwithstanding the foregoing, if BancAmerica Robertson Stephens, on
behalf of the several Underwriters, shall agree to the utilization of Rule 434
of the Rules and Regulations, the Company shall provide to you copies of a
Preliminary Prospectus updated in all respects through the date specified by you
in such quantities as you may from time to time reasonably request.  To the
extent applicable, such documents shall be identical to the electronically
transmitted copies thereof filed with the Commission pursuant to EDGAR, except
to the extent permitted by Regulation S-T.
 
     (e) The Company will make generally available to its securityholders as
soon as practicable, but in any event not later than the forty-fifth (45th) day
following the end of the fiscal quarter first occurring after the first
anniversary of the effective date of the Registration Statement, an earnings
statement (which will be in reasonable detail but need not be audited) complying
with the provisions of Section 11(a) of the Act and covering a twelve (12) month
period beginning after the effective date of the Registration Statement.
 

                                      -18-
<PAGE>
 
     (f) During a period of five (5) years after the date hereof, the Company
will furnish to its stockholders as soon as practicable after the end of each
respective period, annual reports (including financial statements audited by
independent certified public accountants) and unaudited quarterly reports of
operations for each of the first three quarters of the fiscal year, and will
furnish to you and the other several Underwriters hereunder, upon request (i)
statements of operations of the Company for each of the first three (3) quarters
in the form furnished to the Company's stockholders, (ii) a balance sheet of the
Company as of the end of such fiscal year, together with statements of
operations, of stockholders' investment, and of cash flows of the Company for
such fiscal year, accompanied by a copy of the certificate or report thereon of
independent certified public accountants, (iii) as soon as they are available,
copies of all reports (financial or other) mailed to stockholders, (iv) as soon
as they are available, copies of all reports and financial statements furnished
to or filed with the Commission, any securities exchange or the NASD, (v) every
material press release and every material news item or article in respect of the
Company or its affairs which was generally released to stockholders or prepared
by the Company or any of its subsidiaries, and (vi) any additional information
of a public nature concerning the Company or its subsidiaries, or its business
which you may reasonably request.  During such five (5) year period, if the
Company shall have active subsidiaries, the foregoing financial statements shall
be on a consolidated basis to the extent that the accounts of the Company and
its subsidiaries are consolidated, and shall be accompanied by similar financial
statements for any significant subsidiary which is not so consolidated.
 
     (g) The Company will apply the net proceeds from the sale of the Shares
being sold by it in the manner set forth under the caption "Use of Proceeds" in
the Prospectus.
 
     (h) The Company will maintain a transfer agent and, if necessary under the
jurisdiction of incorporation of the Company, a registrar (which may be the same
entity as the transfer agent) for its Common Stock.
 
     (i) If the transactions contemplated hereby are not consummated by reason
of any failure, refusal or inability on the part of the Company or any Selling
Stockholder to perform any agreement on their respective parts to be performed
hereunder or to fulfill any condition of the Underwriters' obligations
hereunder, or if the Company shall terminate this Agreement pursuant to Section
11(a) hereof, or if the Underwriters shall terminate this Agreement pursuant to
Section 11(b)(i), the Company will reimburse the several Underwriters for
all out-of-pocket expenses (including fees and disbursements of Underwriters'
Counsel) incurred by the Underwriters in investigating or preparing to market or
marketing the Shares.
 
     (j) If at any time during the ninety (90) day period after the Registration
Statement becomes effective, any rumor, publication or event relating to or
affecting the Company shall occur as a result of which in your opinion the
market price of the Common Stock has been or is likely to be materially affected
(regardless of whether such rumor, publication or event necessitates a
supplement to or amendment of the Prospectus), the Company will, after written
notice from you advising the Company to the effect set forth above, forthwith
prepare, consult with you concerning the substance of and disseminate a press
release or other public statement, reasonably satisfactory to you, responding to
or commenting on such rumor, publication or event.

                                      -19-
<PAGE>
 
     (k) During the Lock-up Period, the Company will not, without the prior
written consent of BancAmerica Robertson Stephens, effect the Disposition of,
directly or indirectly, any Securities other than (i) the sale of the Company
Shares and the Option Shares to be sold by the Company hereunder, (ii) the
issuance of Common Stock, $0.01 par value per share, upon the exercise of
options outstanding under the Company's presently authorized Employee Stock
Purchase Plan and the Company's presently authorized 1992 Combination Stock
Option Plan, and (iii) the Company's issuance of options under its presently
authorized 1989 Non-Qualified Stock Option Plan for Non-Employee Directors (the
"Option Plans").
 
     (l) During a period of ninety (90) days from the effective date of the
Registration Statement, the Company will not file a registration statement
registering shares under the Option Plans, the Employee Stock Purchase Plan or
other employee benefit plan.
 
     5.  Expenses.
 
     (a) The Company and the Selling Stockholders agree with each Underwriter
that:
 
          (i) The Company will pay and bear all costs and expenses in connection
          with the preparation, printing and filing of the Registration
          Statement (including financial statements, schedules and exhibits),
          Preliminary Prospectuses and the Prospectus and the Incorporated
          Documents and any amendments or supplements thereto; the printing of
          this Agreement, the Agreement Among Underwriters, the Selected Dealer
          Agreement, the Preliminary Blue Sky Survey and any Supplemental Blue
          Sky Survey, the Underwriters' Questionnaire and Power of Attorney, and
          any instruments related to any of the foregoing; the issuance and
          delivery of the Shares hereunder to the several Underwriters,
          including transfer taxes, if any, the cost of all certificates
          representing the Shares and transfer agents' and registrars' fees; the
          fees and disbursements of counsel for the Company; all fees and other
          charges of the Company's independent certified public accountants; the
          cost of furnishing to the several Underwriters copies of the
          Registration Statement (including appropriate exhibits), Preliminary
          Prospectus and the Prospectus and the Incorporated Documents, and any
          amendments or supplements to any of the foregoing; NASD filing fees
          and the cost of qualifying the Shares under the laws of such
          jurisdictions as you may designate (including filing fees and fees and
          disbursements of Underwriters' Counsel in connection with such NASD
          filings and Blue Sky qualifications); and all other expenses directly
          incurred by the Company and the Selling Stockholders in connection
          with the performance of their obligations hereunder. Any additional
          expenses incurred as a result of the sale of the Shares by the Selling
          Stockholders will be borne collectively by the Company and the Selling
          Stockholders. The provisions of this Section 5(a)(i) are intended to
          relieve the Underwriters from the payment of the expenses and costs
          which the Selling Stockholders and the Company hereby agree to pay,
          but shall not affect any agreement which the Selling Stockholders and
          the Company may make, or may

                                      -20-
<PAGE>
 
          have made, for the sharing of any of such expenses and costs. Such
          agreements shall not impair the obligations of the Company and the
          Selling Stockholders hereunder to the several Underwriters.
          
          (ii) In addition to its other obligations under Section 8(a) hereof,
          the Company agrees that, as an interim measure during the pendency of
          any claim, action, investigation, inquiry or other proceeding
          described in Section 8(a) hereof, it will reimburse the Underwriters
          on a monthly basis for all reasonable legal or other expenses incurred
          in connection with investigating or defending any such claim, action,
          investigation, inquiry or other proceeding, notwithstanding the
          absence of a judicial determination as to the propriety and
          enforceability of the Company's obligation to reimburse the
          Underwriters for such expenses and the possibility that such payments
          might later be held to have been improper by a court of competent
          jurisdiction. To the extent that any such interim reimbursement
          payment is so held to have been improper, the Underwriters shall
          promptly return such payment to the Company together with interest,
          compounded daily, determined on the basis of the prime rate (or other
          commercial lending rate for borrowers of the highest credit standing)
          listed from time to time in The Wall Street Journal which represents
          the base rate on corporate loans posted by a substantial majority of
          the nation's thirty (30) largest banks (the "Prime Rate"). Any such
          interim reimbursement payments which are not made to the Underwriters
          within thirty (30) days of a request for reimbursement shall bear
          interest at the Prime Rate from the date of such request.
          
          (iii) In addition to their other obligations under Section 8(b)
          hereof, each Selling Stockholder agrees that, as an interim measure
          during the pendency of any claim, action, investigation, inquiry or
          other proceeding described in Section 8(b) hereof relating to such
          Selling Stockholder, it will reimburse the Underwriters on a monthly
          basis for all reasonable legal or other expenses incurred in
          connection with investigating or defending any such claim, action,
          investigation, inquiry or other proceeding, notwithstanding the
          absence of a judicial determination as to the propriety and
          enforceability of such Selling Stockholder's obligation to reimburse
          the Underwriters for such expenses and the possibility that such
          payments might later be held to have been improper by a court of
          competent jurisdiction. To the extent that any such interim
          reimbursement payment is so held to have been improper, the
          Underwriters shall promptly return such payment to the Selling
          Stockholders, together with interest, compounded daily, determined on
          the basis of the Prime Rate. Any such interim reimbursement payments
          which are not made to the Underwriters within thirty (30) days of a
          request for reimbursement shall bear interest at the Prime Rate from
          the date of such request.
          
     (b) In addition to their other obligations under Section 8(c) hereof, the
Underwriters severally and not jointly agree that, as an interim measure during
the pendency of any claim, action,

                                      -21-
<PAGE>
 
investigation, inquiry or other proceeding described in Section 8(c) hereof,
they will reimburse the Company and each Selling Stockholder on a monthly basis
for all reasonable legal or other expenses incurred in connection with
investigating or defending any such claim, action, investigation, inquiry or
other proceeding, notwithstanding the absence of a judicial determination as to
the propriety and enforceability of the Underwriters' obligation to reimburse
the Company and each such Selling Stockholder for such expenses and the
possibility that such payments might later be held to have been improper by a
court of competent jurisdiction. To the extent that any such interim
reimbursement payment is so held to have been improper, the Company and each
such Selling Stockholder shall promptly return such payment to the Underwriters
together with interest, compounded daily, determined on the basis of the Prime
Rate. Any such interim reimbursement payments which are not made to the Company
and each such Selling Stockholder within thirty (30) days of a request for
reimbursement shall bear interest at the Prime Rate from the date of such
request.
 
     (c) It is agreed that any controversy arising out of the operation of the
interim reimbursement arrangements set forth in Sections 5(a)(ii), 5(a)(iii) and
5(b) hereof, including the amounts of any requested reimbursement payments, the
method of determining such amounts and the basis on which such amounts shall be
apportioned among the reimbursing parties, shall be settled by arbitration
conducted under the provisions of the Constitution and Rules of the Board of
Governors of the New York Stock Exchange, Inc. or pursuant to the Code of
Arbitration Procedure of the NASD.  Any such arbitration must be commenced by
service of a written demand for arbitration or a written notice of intention to
arbitrate, therein electing the arbitration tribunal.  In the event the party
demanding arbitration does not make such designation of an arbitration tribunal
in such demand or notice, then the party responding to said demand or notice is
authorized to do so.  Any such arbitration will be limited to the operation of
the interim reimbursement provisions contained in Sections 5(a)(ii), 5(a)(iii)
and 5(b) hereof and will not resolve the ultimate propriety or enforceability of
the obligation to indemnify for expenses which is created by the provisions of
Sections 8(a), 8(b) and 8(c) hereof or the obligation to contribute to expenses
which is created by the provisions of Section 8(e) hereof.
 
     6.  Conditions of Underwriters' Obligations.  The obligations of the
         ---------------------------------------                         
several Underwriters to purchase and pay for the Shares as provided herein shall
be subject to the accuracy, as of the date hereof and the Closing Date and any
later date on which Option Shares are to be purchased, as the case may be, of
the representations and warranties of the Company and the Selling Stockholders
herein, to the performance by the Company and the Selling Stockholders of their
respective obligations hereunder and to the following additional conditions:
 
     (a) The Registration Statement shall have become effective not later than
2:00 P.M., San Francisco time, on the date following the date of this Agreement,
or such later date as shall be consented to in writing by you; and no stop order
suspending the effectiveness thereof shall have been issued and no proceedings
for that purpose shall have been initiated or, to the knowledge of the Company,
any Selling Stockholder or any Underwriter, threatened by the Commission, and
any request of the Commission for additional information (to be included in the
Registration Statement or the Prospectus or any Incorporated Document or
otherwise) shall have been complied with to the satisfaction of Underwriters'
Counsel.
 
     (b) All corporate proceedings and other legal matters in connection with
this Agreement, the form of Registration Statement and the Prospectus, and the
registration,

                                      -22-
<PAGE>
 
authorization, issue, sale and delivery of the Shares, shall have been
reasonably satisfactory to Underwriters' Counsel, and such counsel shall have
been furnished with such papers and information as they may reasonably have
requested to enable them to pass upon the matters referred to in this Section.
 
     (c) Subsequent to the execution and delivery of this Agreement and prior to
the Closing Date, or any later date on which Option Shares are to be purchased,
as the case may be, there shall not have been any change in the condition
(financial or otherwise), earnings, operations, business or business prospects
of the Company and its subsidiaries considered as one enterprise from that set
forth in the Registration Statement or Prospectus, which, in your sole judgment,
is material and adverse and that makes it, in your sole judgment, impracticable
or inadvisable to proceed with the public offering of the Shares as contemplated
by the Prospectus.
 
     (d) You shall have received on the Closing Date and on any later date on
which Option Shares are to be purchased, as the case may be, the following
opinion of Brown, Rudnick, Freed & Gesmer, counsel for the Company and each of
the Selling Stockholders, dated the Closing Date or such later date on which
Option Shares are to be purchased addressed to the Underwriters and with
reproduced copies or signed counterparts thereof for each of the Underwriters,
to the effect that:
 
          (i)  The Company and each subsidiary has been duly incorporated and is
          validly existing as a corporation in good standing under the laws of
          the jurisdiction of its incorporation;
 
          (ii) The Company and each subsidiary has the corporate power and
          authority to own, lease and operate its properties and to conduct its
          business as described in the Prospectus;
          
          (iii) The Company and each subsidiary is duly qualified to do business
          as a foreign corporation and is in good standing in each jurisdiction,
          if any, in which the ownership or leasing of its properties or the
          conduct of its business requires such qualification, except where the
          failure to be so qualified or be in good standing would not have a
          material adverse effect on the condition (financial or otherwise),
          earnings, operations or business of the Company and its subsidiaries
          considered as one enterprise. To such counsel's knowledge, the Company
          does not own or control, directly or indirectly, any corporation,
          association or other entity other than ABIOMED Cardiovascular, Inc.,
          ABIODENT, Inc., ABIOMED R&D, Inc., ABD Holding Company, Inc., Abiomed
          Research & Development, Inc. and Abiomed Limited Partnership;
          
          (iv) The authorized, issued and outstanding capital stock of the
          Company is as set forth in the Prospectus under the caption
          "Capitalization" as of the dates stated therein, the issued and
          outstanding shares of capital stock of the Company (including the
          Selling Stockholder Shares) have been duly and validly issued and are
          fully paid and nonassessable, and, to such counsel's knowledge, will

                                      -23-
<PAGE>
 
          not have been issued in violation of or subject to any preemptive
          right, co-sale right, registration right, right of first refusal or
          other similar right;
          
          (v)  All issued and outstanding shares of capital stock or partnership
          interests, as applicable,  of each subsidiary of the Company have been
          duly authorized and validly issued and are fully paid and
          nonassessable, and, to such counsel's knowledge, have not been issued
          in violation of or subject to any preemptive right, co-sale right,
          registration right, right of first refusal or other similar right and
          are owned by the Company free and clear of any pledge, lien, security
          interest, encumbrance, claim or equitable interest, except for Abiomed
          Limited Partnership, of which the Company owns 61.7% of the
          partnership interests;
 
          (vi) The Firm Shares and the Option Shares to be issued by the Company
          pursuant to the terms of this Agreement have been duly authorized and,
          upon issuance and delivery against payment therefor in accordance with
          the terms hereof, will be duly and validly issued and fully paid and
          nonassessable, and will not have been issued in violation of or
          subject to any preemptive right, co-sale right, registration right,
          right of first refusal or other similar right (other than such rights
          as are duly and validly waived);
 
          (vii) The Company has the corporate power and authority to enter into
          this Agreement and the Custody Agreement and to issue, sell and
          deliver to the Underwriters the Shares to be issued and sold by it
          hereunder;
          
          (viii) Each of this Agreement and the Custody Agreement has been duly
          authorized by all necessary corporate action on the part of the
          Company and has been duly executed and delivered by the Company and,
          assuming due authorization, execution and delivery by you, is a valid
          and binding agreement of the Company, enforceable in accordance with
          its terms, except insofar as indemnification provisions may be limited
          by applicable law and except as enforceability may be limited by
          bankruptcy, insolvency, reorganization, moratorium or similar laws
          relating to or affecting creditors' rights generally or by general
          equitable principles;
          
          (ix) The Registration Statement has become effective under the Act
          and, to such counsel's knowledge, no stop order suspending the
          effectiveness of the Registration Statement has been issued and no
          proceedings for that purpose have been instituted or are pending or
          threatened under the Act;
 
          (x) The Registration Statement and the Prospectus, and each amendment
          or supplement thereto (other than the financial statements (including
          supporting schedules) and financial data derived therefrom as to which
          such counsel need express no opinion), as of the effective date of the
          Registration Statement, complied as to form in all material respects
          with the requirements of the Act and the

                                      -24-
<PAGE>
 
          applicable Rules and Regulations; and each of the Incorporated
          Documents (other than the financial statements (including supporting
          schedules) and the financial data derived therefrom as to which such
          counsel need express no opinion) complied when filed pursuant to the
          Exchange Act as to form in all material respects with the requirements
          of the Act and the Rules and Regulations and the Exchange Act and the
          applicable rules and regulations of the Commission thereunder;
 
          (xi) The terms and provisions of the capital stock of the Company
          conform in all material respects to the description thereof contained
          in the Registration Statement and the Prospectus, and the statements
          under the captions "Capitalization" and "Description of Capital
          Stock," to the extent that they constitute summaries of matters of law
          or legal conclusions, have been reviewed by such counsel and are
          accurate and complete statements or summaries of the matters set forth
          therein; and the forms of certificates evidencing the Common Stock and
          filed as exhibits to the Registration Statement comply with Delaware
          law;
 
          (xii) The description in the Registration Statement and the Prospectus
          of the charter and bylaws of the Company and of statutes are accurate
          and fairly present the information required to be presented by the Act
          and the applicable Rules and Regulations;
 
          (xiii) To such counsel's knowledge, there are no agreements,
          contracts, leases or documents to which the Company is a party of a
          character required to be described or referred to in the Registration
          Statement or Prospectus or any Incorporated Document or to be filed as
          an exhibit to the Registration Statement or any Incorporated Document
          which are not described or referred to therein or filed as required;
 
          (xiv)  The performance of this Agreement and the consummation of the
          transactions herein contemplated (other than performance of the
          Company's indemnification obligations hereunder, concerning which no
          opinion need be expressed) will not (a) result in any violation of the
          Company's charter or bylaws or (b) to such counsel's knowledge, result
          in a material breach or violation of any of the terms and provisions
          of, or constitute a default under, any bond, debenture, note or other
          evidence of indebtedness, or any lease, contract, indenture, mortgage,
          deed of trust, loan agreement, joint venture or other agreement or
          instrument known to such counsel to which the Company is a party or by
          which its properties are bound, or any applicable statute, rule or
          regulation known to such counsel or, to such counsel's knowledge, any
          law, order, rule, regulation, writ, injunction, judgment or decree of
          any court, government or governmental agency or body having
          jurisdiction over the Company or any of its subsidiaries, or over any
          of their properties or operations;
 
          (xv) No consent, approval, authorization or order of or qualification
          with any court, government or governmental agency or body having

                                      -25-
<PAGE>
 
          jurisdiction over the Company or any of its subsidiaries, or over any
          of their properties or operations is necessary in connection with the
          consummation by the Company of the transactions herein contemplated,
          except such as have been obtained under the Act or such as may be
          required under state or other securities or Blue Sky laws in
          connection with the purchase and the distribution of the Shares by the
          Underwriters;
 
          (xvi)  To such counsel's knowledge, there are no legal or governmental
          proceedings pending or threatened against the Company or any of its
          subsidiaries of a character required to be disclosed in the
          Registration Statement or the Prospectus or any Incorporated Document
          by the Act or the Rules and Regulations or by the Exchange Act or the
          applicable rules and regulations of the Commission thereunder, other
          than those described therein;
 
          (xvii) To such counsel's knowledge, neither the Company nor any of its
          subsidiaries is presently (a) in material violation of its respective
          charter or bylaws, or (b) in material breach of any applicable
          statute, rule or regulation known to such counsel or, to such
          counsel's knowledge, any order, writ or decree of any court or
          governmental agency or body having jurisdiction over the Company or
          any of its subsidiaries, or over any of their properties or
          operations;
 
          (xviii)  To such counsel's knowledge, except as set forth in the
          Registration Statement and Prospectus and any Incorporated Document,
          no holders of Common Stock or other securities of the Company have
          registration rights with respect to securities of the Company and,
          except as set forth in the Registration Statement and Prospectus, all
          holders of securities of the Company having rights known to such
          counsel to registration of such shares of Common Stock or other
          securities, because of the filing of the Registration Statement by the
          Company have, with respect to the offering contemplated thereby,
          waived such rights or such rights have expired by reason of lapse of
          time following notification of the Company's intent to file the
          Registration Statement or have included securities in the Registration
          Statement pursuant to the exercise of and in full satisfaction of such
          rights;
 
          (xix)  Each Selling Stockholder which is not a natural person has full
          right, power and authority to enter into and to perform its
          obligations under the Power of Attorney and Custody Agreement to be
          executed and delivered by it in connection with the transactions
          contemplated herein; the Power of Attorney and Custody Agreement of
          each Selling Stockholder that is not a natural person has been duly
          authorized by such Selling Stockholder; the Power of Attorney and
          Custody Agreement of each Selling Stockholder has been duly executed
          and delivered by or on behalf of such Selling Stockholder; and the
          Power of Attorney and Custody Agreement of each Selling Stockholder
          constitutes the valid and binding agreement of such Selling
          Stockholder, enforceable in accordance with its terms, except insofar
          as indemnification provisions may be limited by applicable

                                      -26-
<PAGE>
 
          law and except as enforceability may be limited by bankruptcy,
          insolvency, reorganization, moratorium or other similar laws relating
          to or affecting creditors' rights generally or by general equitable
          principles;
 
          (xx) Each of the Selling Stockholders has full right, power and
          authority to enter into and to perform its obligations under this
          Agreement and to sell, transfer, assign and deliver the Shares to be
          sold by such Selling Stockholder hereunder;
 
          (xxi) This Agreement has been duly authorized by each Selling
          Stockholder that is not a natural person and has been duly executed
          and delivered by or on behalf of each Selling Stockholder; and
 
          (xxii) Upon the delivery of and payment for the Shares as contemplated
          in this Agreement, each of the Underwriters will acquire all of the
          rights of each Selling Stockholder to the Shares purchased by it from
          such Selling Stockholder, and each Underwriter will also acquire such
          Shares free of any "adverse claim" (within the meaning of Section 8-
          302(2) of the Uniform Commercial Code). In rendering such opinion,
          such counsel may assume that the Underwriters are without notice of
          any defect in the title of the Shares being purchased from the Selling
          Stockholders.
          
          (xxiii) The statements in the Registration Statement and the
          Prospectus under the captions "Risk Factors Government Regulation" and
          "Business Government Regulation," to the extent that they constitute
          summaries of matters of law or legal conclusions, have been reviewed
          by such counsel and are accurate and complete statements or summaries
          of the matters set forth therein.

          (xxiv) To such counsel's knowledge, (x) neither the Company nor any of
          its subsidiaries is in material violation of the Food, Drug and
          Cosmetic Act, as amended, or any of the rules and regulations of the
          FDA, including the FDA's Quality Assurance Regulations or any of the
          rules and regulations of any other federal, state or foreign
          regulatory body or agency, and (y) there is not any pending or
          threatened FDA enforcement action against the Company or any of its
          subsidiaries and there is not any pending or threatened investigation
          by the FDA of the Company or any of its subsidiaries or any of their
          products.
          
          In addition, such counsel shall state that such counsel has
participated in conferences with officials and other representatives of the
Company, the Representatives, Underwriters' Counsel and the independent
certified public accountants of the Company, at which such conferences the
contents of the Registration Statement and Prospectus and related matters were
discussed, and although they have not verified the accuracy or completeness of
the statements contained in the Registration Statement or the Prospectus,
nothing has come to the attention of such counsel which leads them to believe
that, at the time the Registration Statement became effective and at all times
subsequent thereto up to and on the Closing Date and on any later date on which

                                      -27-
<PAGE>
 
Option Shares are to be purchased, the Registration Statement and any amendment
or supplement thereto and any Incorporated Document, when such documents became
effective or were filed with the Commission (other than the financial statements
including supporting schedules and other financial and statistical information
derived therefrom, as to which such counsel need express no comment) contained
any untrue statement of a material fact or omitted to state a material fact
required to be stated therein or necessary to make the statements therein not
misleading, or at the Closing Date or any later date on which the Option Shares
are to be purchased, as the case may be, the Registration Statement, the
Prospectus and any amendment or supplement thereto and any Incorporated Document
(except as aforesaid) contained any untrue statement of a material fact or
omitted to state a material fact necessary to make the statements therein, in
the light of the circumstances under which they were made, not misleading. Such
counsel shall also state that the conditions for the use of Form S-3 set forth
in the General Instructions thereto have been satisfied.
 
     Counsel rendering the foregoing opinion may rely as to questions of law not
involving the laws of the United States, the Commonwealth of Massachusetts or
the State of Delaware upon opinions of local counsel, and as to questions of
fact upon representations or certificates of officers of the Company, the
Selling Stockholders or officers of the Selling Stockholders (when the Selling
Stockholder is not a natural person), and of government officials, in which case
their opinion is to state that they are so relying and that they have no
knowledge of any material misstatement or inaccuracy in any such opinion,
representation or certificate.  Copies of any opinion, representation or
certificate so relied upon shall be delivered to you, as Representatives of the
Underwriters, and to Underwriters' Counsel.
 
     (e) You shall have received on the Closing Date and on any later date on
which Option Shares are to be purchased, as the case may be, an opinion of
Testa, Hurwitz & Thibeault, LLP, in form and substance satisfactory to you, with
respect to the sufficiency of all such corporate proceedings and other legal
matters relating to this Agreement and the transactions contemplated hereby as
you may reasonably require, and the Company shall have furnished to such counsel
such documents as they may have requested for the purpose of enabling them to
pass upon such matters.

     (f) You shall have received on the Closing Date and on any later date on
which Option Shares are to be purchased, as the case may be, the opinion of each
of Lahive & Cockfield, LLP, and Wolf, Greenfield & Sachs, PC, patent counsel to
the Company, dated the Closing Date or such later date on which Option Shares
are to be purchased, as applicable, in form and substance satisfactory to you,
addressed to the Underwriters and with reproduced copies or signed counterparts
thereof for each of the Underwriters, to the effect that they serve as patent
counsel to Company, and addressing such other legal matters relating to this
Agreement and the transactions contemplated hereby as you may reasonably
require.
 
     (g) You shall have received on the Closing Date and on any later date on
which Option Shares are to be purchased, as the case may be, a letter from
Arthur Andersen LLP addressed to the Underwriters, dated the Closing Date or
such later date on which Option Shares are to be purchased, as the case may be,
confirming that they are independent certified public accountants with respect
to the Company within the meaning of the Act and the applicable

                                      -28-
<PAGE>
 
published Rules and Regulations and based upon the procedures described in such
letter delivered to you concurrently with the execution of this Agreement
(herein called the "Original Letter"), but carried out to a date not more than
five (5) business days prior to the Closing Date or such later date on which
Option Shares are to be purchased, as the case may be, (i) confirming, to the
extent true, that the statements and conclusions set forth in the Original
Letter are accurate as of the Closing Date or such later date on which Option
Shares are to be purchased, as the case may be, and (ii) setting forth any
revisions and additions to the statements and conclusions set forth in the
Original Letter which are necessary to reflect any changes in the facts
described in the Original Letter since the date of such letter, or to reflect
the availability of more recent financial statements, data or information. The
letter shall not disclose any change in the condition (financial or otherwise),
earnings, operations, business or business prospects of the Company and its
subsidiaries considered as one enterprise from that set forth in the
Registration Statement or Prospectus, which, in your sole judgment, is material
and adverse and that makes it, in your sole judgment, impracticable or
inadvisable to proceed with the public offering of the Shares as contemplated by
the Prospectus. The Original Letter from Arthur Andersen LLP shall be addressed
to or for the use of the Underwriters in form and substance satisfactory to the
Underwriters and shall (i) represent, to the extent true, that they are
independent certified public accountants with respect to the Company within the
meaning of the Act and the applicable published Rules and Regulations, (ii) set
forth their opinion with respect to their examination of the consolidated
balance sheet of the Company as of March 31, 1997 and related consolidated
statements of operations, shareholders' investment, and cash flows for the
twelve (12) months ended March 31, 1997, (iii) state that Arthur Andersen LLP
has performed the procedures set out in Statement on Auditing Standards No. 71
("SAS 71") for a review of interim financial information and providing the
report of Arthur Andersen LLP as described in SAS 71 on the financial statements
for each of the quarters in the two-quarter period ended September 30, 1997 (the
"Quarterly Financial Statements"), (iv) state that in the course of such review,
nothing came to their attention that leads them to believe that any material
modifications need to be made to any of the Quarterly Financial Statements in
order for them to be in compliance with generally accepted accounting principles
consistently applied across the periods presented, and (v) address other matters
agreed upon by Arthur Andersen LLP and you. In addition, you shall have received
from Arthur Andersen LLP a letter addressed to the Company and made available to
you for the use of the Underwriters stating that their review of the Company's
system of internal accounting controls, to the extent they deemed necessary in
establishing the scope of their examination of the Company's consolidated
financial statements as of March 31, 1997, did not disclose any weaknesses in
internal controls that they considered to be material weaknesses.
 
     (h) You shall have received on the Closing Date and on any later date on
which Option Shares are to be purchased, as the case may be, a certificate of
the Company, dated the Closing Date or such later date on which Option Shares
are to be purchased, as the case may be, signed by the Chief Executive Officer
and Chief Financial Officer of the Company, to the effect that, and you shall be
satisfied that:
 
          (i) The representations and warranties of the Company in this
          Agreement are true and correct, as if made on and as of the Closing
          Date or any later date on which Option Shares are to be purchased, as
          the case may be, and the

                                      -29-
<PAGE>
 
          Company has complied with all the agreements and satisfied all the
          conditions on its part to be performed or satisfied at or prior to the
          Closing Date or any later date on which Option Shares are to be
          purchased, as the case may be;
          
          (ii) No stop order suspending the effectiveness of the Registration
          Statement has been issued and no proceedings for that purpose have
          been instituted or are pending or threatened under the Act;
 
          (iii) When the Registration Statement became effective and at all
          times subsequent thereto up to the delivery of such certificate, the
          Registration Statement and the Prospectus, and any amendments or
          supplements thereto and the Incorporated Documents, when such
          Incorporated Documents became effective or were filed with the
          Commission, contained all material information required to be included
          therein by the Act and the Rules and Regulations or the Exchange Act
          and the applicable rules and regulations of the Commission thereunder,
          as the case may be, and in all material respects conformed to the
          requirements of the Act and the Rules and Regulations or the Exchange
          Act and the applicable rules and regulations of the Commission
          thereunder, as the case may be, the Registration Statement, and any
          amendment or supplement thereto, did not and does not include any
          untrue statement of a material fact or omit to state a material fact
          required to be stated therein or necessary to make the statements
          therein not misleading, the Prospectus, and any amendment or
          supplement thereto, did not and does not include any untrue statement
          of a material fact or omit to state a material fact necessary to make
          the statements therein, in the light of the circumstances under which
          they were made, not misleading, and, since the effective date of the
          Registration Statement, there has occurred no event required
          to be set forth in an amended or supplemented Prospectus which has not
          been so set forth;
 
          (iv) Subsequent to the respective dates as of which information is
          given in the Registration Statement and Prospectus, there has not been
          (a) any material adverse change in the condition (financial or
          otherwise), earnings, operations, business or business prospects of
          the Company and its subsidiaries considered as one enterprise, (b) any
          transaction that is material to the Company and its subsidiaries
          considered as one enterprise, except transactions entered into in the
          ordinary course of business, (c) any obligation, direct or contingent,
          that is material to the Company and its subsidiaries considered as one
          enterprise, incurred by the Company or its subsidiaries, except
          obligations incurred in the ordinary course of business, (d) any
          change in the capital stock or outstanding indebtedness of the Company
          or any of its subsidiaries that is material to the Company and its
          subsidiaries considered as one enterprise, (e) any dividend or
          distribution of any kind declared, paid or made on the capital stock
          of the Company or any of its subsidiaries, or (f) any loss or damage
          (whether or not insured) to the property of the Company or any of its
          subsidiaries which has been sustained or will have been sustained
          which has a material adverse effect on the condition (financial or
         

                                      -30-
<PAGE>
 
          otherwise), earnings, operations, business or business prospects of
          the Company and its subsidiaries considered as one enterprise; and

          (v) The additional shares of Common Stock to be offered pursuant to
          the terms of this Agreement has been approved for quotation on The
          Nasdaq National Market.
          
     (i) You shall be satisfied that, and you shall have received a certificate,
dated the Closing Date from the Attorneys for each Selling Stockholder to the
effect that, as of the Closing Date, they have not been informed that:
 
          (i) The representations and warranties made by such Selling
          Stockholder herein are not true or correct in any material respect on
          the Closing Date; or
          
          (ii) Such Selling Stockholder has not complied with any obligation or
          satisfied any condition which is required to be performed or satisfied
          on the part of such Selling Stockholder at or prior to the Closing
          Date.
 
     (j) The Company shall have obtained and delivered to you prior to the date
hereof an agreement in writing from each executive officer and each director of
the Company, each Selling Stockholder and Genzyme Corporation that such person
will not, during the Lock-up Period, effect the Disposition of any Securities
now owned or hereafter acquired directly by such person or with respect to which
such person has or hereafter acquires the power of disposition, otherwise than
(i) as a bona fide gift or gifts, provided the donee or donees thereof agree in
writing to be bound by this restriction, (ii) as a distribution to partners or
shareholders of such person, provided that the distributees thereof agree in
writing to be bound by the terms of this restriction, or (iii) with the prior
written consent of BancAmerica Robertson Stephens. The foregoing restriction
shall have been expressly agreed to preclude the holder of the Securities from
engaging in any hedging or other transaction which is designed to or reasonably
expected to lead to or result in a Disposition of Securities during the Lock-up
Period, even if such Securities would be disposed of by someone other than the
such holder. Such prohibited hedging or other transactions would include,
without limitation, any short sale (whether or not against the box) or any
purchase, sale or grant of any right (including, without limitation, any put or
call option) with respect to any Securities or with respect to any security
(other than a broad-based market basket or index) that includes, relates to or
derives any significant part of its value from Securities. Furthermore, such
person will have also agreed and consented to the entry of stop transfer
instructions with the Company's transfer agent against the transfer of the
Securities held by such person except in compliance with this restriction.
 
     (k) The Company and the Selling Stockholders shall have furnished to you
such further certificates and documents as you shall reasonably request
(including certificates of officers of the Company, the Selling Stockholders or
officers of the Selling Stockholders (when the Selling Stockholder is not a
natural person) as to the accuracy of the representations and warranties of the
Company and the Selling Stockholders herein, as to the performance by the

                                      -31-
<PAGE>
 
Company and the Selling Stockholders of its or their respective obligations
hereunder and as to the other conditions concurrent and precedent to the
obligations of the Underwriters hereunder.
 
     All such opinions, certificates, letters and documents will be in
compliance with the provisions hereof only if they are reasonably satisfactory
to Underwriters' Counsel.  The Company and the Selling Stockholders will furnish
you with such number of conformed copies of such opinions, certificates, letters
and documents as you shall reasonably request.
 
     7.  Option Shares.
         ------------- 
 
     (a) On the basis of the representations, warranties and agreements herein
contained, but subject to the terms and conditions herein set forth, the Company
hereby grants to the several Underwriters, for the purpose of covering over-
allotments in connection with the distribution and sale of the Firm Shares only,
a nontransferable option to purchase up to an aggregate of 360,000 Option Shares
at the purchase price per share for the Firm Shares set forth in Section 3
hereof.  Such option may be exercised by the Representatives on behalf of the
several Underwriters on one (1) or more occasions in whole or in part during the
period of thirty (30) days after the date on which the Firm Shares are initially
offered to the public, by giving written notice to the Company.  The number of
Option Shares to be purchased by each Underwriter upon the exercise of such
option shall be the same proportion of the total number of Option Shares to be
purchased by the several Underwriters pursuant to the exercise of such option as
the number of Firm Shares purchased by such Underwriter (set forth in Schedule A
                                                                      ----------
hereto) bears to the total number of Firm Shares purchased by the several
Underwriters (set forth in Schedule A hereto), adjusted by the Representatives
                           ----------                                         
in such manner as to avoid fractional shares.

     Delivery of definitive certificates for the Option Shares to be purchased
by the several Underwriters pursuant to the exercise of the option granted by
this Section 7 shall be made against payment of the purchase price therefor by
the several Underwriters by certified or official bank check or checks drawn in
next-day funds, payable to the order of the Company (and the Company agrees not
to deposit any such check in the bank on which it is drawn, and not to take any
other action with the purpose or effect of receiving immediately available
funds, until the business day following the date of its delivery to the
Company).  In the event of any breach of the foregoing, the Company shall
reimburse the Underwriters for the interest lost and any other expenses borne by
them by reason of such breach.  Such delivery and payment shall take place at
the offices of Brown, Rudnick, Freed & Gesmer, One Financial Center, Boston, MA
02111 or at such other place as may be agreed upon among the Representatives and
the Company (i) on the Closing Date, if written notice of the exercise of such
option is received by the Company at least two (2) full business days prior to
the Closing Date, or (ii) on a date which shall not be later than the third
(3rd) full business day following the date the Company receives written notice
of the exercise of such option, if such notice is received by the Company less
than two (2) full business days prior to the Closing Date.
 
     The certificates for the Option Shares to be so delivered will be made
available to you at such office or such other location including, without
limitation, in New

                                      -32-
<PAGE>
 
York City, as you may reasonably request for checking at least one (1) full
business day prior to the date of payment and delivery and will be in such names
and denominations as you may request, such request to be made at least two (2)
full business days prior to such date of payment and delivery. If the
Representatives so elect, delivery of the Option Shares may be made by credit
through full fast transfer to the accounts at The Depository Trust Company
designated by the Representatives.
 
     It is understood that you, individually, and not as the Representatives of
the several Underwriters, may (but shall not be obligated to) make payment of
the purchase price on behalf of any Underwriter or Underwriters whose check or
checks shall not have been received by you prior to the date of payment and
delivery for the Option Shares to be purchased by such Underwriter or
Underwriters.  Any such payment by you shall not relieve any such Underwriter or
Underwriters of any of its or their obligations hereunder.
 
     (b) Upon exercise of any option provided for in Section 7(a) hereof, the
obligations of the several Underwriters to purchase such Option Shares will be
subject (as of the date hereof and as of the date of payment and delivery for
such Option Shares) to the accuracy of and compliance with the representations,
warranties and agreements of the Company and the Selling Stockholders herein, to
the accuracy of the statements of the Company, the Selling Stockholders and
officers of the Company made pursuant to the provisions hereof, to the
performance by the Company and the Selling Stockholders of their respective
obligations hereunder, to the conditions set forth in Section 6 hereof, and to
the condition that all proceedings taken at or prior to the payment date in
connection with the sale and transfer of such Option Shares shall be
satisfactory in form and substance to you and to Underwriters' Counsel, and you
shall have been furnished with all such documents, certificates and opinions as
you may request in order to evidence the accuracy and completeness of any of the
representations, warranties or statements, the performance of any of the
covenants or agreements of the Company and the Selling Stockholders or the
satisfaction of any of the conditions herein contained.
 
     8.  Indemnification and Contribution.
         -------------------------------- 
 
     (a) The Company agrees to indemnify and hold harmless each Underwriter
against any losses, claims, damages or liabilities, joint or several, to which
such Underwriter may become subject (including, without limitation, in its
capacity as an Underwriter or as a "qualified independent underwriter" within
the meaning of Schedule E of the Bylaws of the NASD), under the Act, the
Exchange Act or otherwise, specifically including, but not limited to, losses,
claims, damages or liabilities (or actions in respect thereof) arising out of or
based upon (i) any breach of any representation, warranty, agreement or covenant
of the Company herein contained, (ii) any untrue statement or alleged untrue
statement of any material fact contained in the Registration Statement or any
amendment or supplement thereto, including any Incorporated Document, or the
omission or alleged omission to state therein a material fact required to be
stated therein or necessary to make the statements therein not misleading, or
(iii) any untrue statement or alleged untrue statement of any material fact
contained in any Preliminary Prospectus or the Prospectus or any amendment or
supplement thereto, or the omission or alleged omission to state therein a
material fact required to be stated therein or necessary to make the statements
therein, in

                                      -33-
<PAGE>
 
the light of the circumstances under which they were made, not misleading, and
agrees to reimburse each Underwriter for any legal or other expenses reasonably
incurred by it in connection with investigating or defending any such loss,
claim, damage, liability or action; provided, however, that the Company
                                    --------  -------          
shall not be liable in any such case to the extent that any such loss,
claim, damage, liability or action arises out of or is based upon an untrue
statement or alleged untrue statement or omission or alleged omission made in
the Registration Statement, such Preliminary Prospectus or the Prospectus, or
any such amendment or supplement thereto, in reliance upon, and in conformity
with, written information relating to any Underwriter furnished to the Company
by such Underwriter, directly or through you, specifically for use in the
preparation thereof and, provided further, that the indemnity agreement provided
                         -------- -------                                       
in this Section 8(a) with respect to any Preliminary Prospectus shall not inure
to the benefit of any Underwriter from whom the person asserting any losses,
claims, damages, liabilities or actions based upon any untrue statement or
alleged untrue statement of material fact or omission or alleged omission to
state therein a material fact purchased Shares, if a copy of the Prospectus in
which such untrue statement or alleged untrue statement or omission or alleged
omission was corrected had not been sent or given to such person within the time
required by the Act and the Rules and Regulations, unless such failure is the
result of noncompliance by the Company with Section 4(d) hereof.
 
     The indemnity agreement in this Section 8(a) shall extend upon the same
terms and conditions to, and shall inure to the benefit of, each person, if any,
who controls any Underwriter within the meaning of the Act or the Exchange Act.
This indemnity agreement shall be in addition to any liabilities which the
Company may otherwise have.
 
     (b) Each Selling Stockholder, severally and not jointly, agrees to
indemnify and hold harmless each Underwriter against any losses, claims, damages
or liabilities, joint or several, to which such Underwriter may become subject
(including, without limitation, in its capacity as an Underwriter or as a
"qualified independent underwriter" within the meaning of Schedule E or the
Bylaws of the NASD) under the Act, the Exchange Act or otherwise, specifically
including, but not limited to, losses, claims, damages or liabilities (or
actions in respect thereof) arising out of or based upon (i) any breach of any
representation, warranty, agreement or covenant of such Selling Stockholder
herein contained, (ii) any untrue statement or alleged untrue statement of any
material fact contained in the Registration Statement or any amendment or
supplement thereto, including any Incorporated Document, or the omission or
alleged omission to state therein a material fact required to be stated therein
or necessary to make the statements therein not misleading, or (iii) any untrue
statement or alleged untrue statement of any material fact contained in any
Preliminary Prospectus or the Prospectus or any amendment or supplement thereto,
or the omission or alleged omission to state therein a material fact necessary
to make the statements therein, in the light of the circumstances under which
they were made, not misleading, in the case of subparagraphs (ii) and (iii) of
this Section 8(b) to the extent, but only to the extent, that such untrue
statement or alleged untrue statement or omission or alleged omission was made
in reliance upon and in conformity with written information furnished to the
Company or such Underwriter by such Selling Stockholder, directly or through
such Selling Stockholder's representatives, specifically for use in the
preparation thereof, and agrees to reimburse each Underwriter for any legal or
other expenses reasonably incurred by it in connection with investigating or
defending any such loss, claim, damage, liability or action; provided, however,
                                                             -------- -------
that the indemnity agreement

                                      -34-
<PAGE>
 
provided in this Section 8(b) with respect to any Preliminary Prospectus shall
not inure to the benefit of any Underwriter from whom the person asserting any
losses, claims, damages, liabilities or actions based upon any untrue statement
or alleged untrue statement of a material fact or omission or alleged omission
to state therein a material fact purchased Shares, if a copy of the Prospectus
in which such untrue statement or alleged untrue statement or omission or
alleged omission was corrected had not been sent or given to such person within
the time required by the Act and the Rules and Regulations, unless such failure
is the result of noncompliance by the Company with Section 4(d) hereof.
 
     The indemnity agreement in this Section 8(b) shall extend upon the same
terms and conditions to, and shall inure to the benefit of, each person, if any,
who controls any Underwriter within the meaning of the Act or the Exchange Act.
This indemnity agreement shall be in addition to any liabilities which such
Selling Stockholder may otherwise have.]
 
     (c) Each Underwriter, severally and not jointly, agrees to indemnify and
hold harmless the Company and each Selling Stockholder against any losses,
claims, damages or liabilities, joint or several, to which the Company or such
Selling Stockholder may become subject under the Act or otherwise, specifically
including, but not limited to, losses, claims, damages or liabilities (or
actions in respect thereof) arising out of or based upon (i) any breach of any
representation, warranty, agreement or covenant of such Underwriter herein
contained, (ii) any untrue statement or alleged untrue statement of any material
fact contained in the Registration Statement or any amendment or supplement
thereto, or the omission or alleged omission to state therein a material fact
required to be stated therein or necessary to make the statements therein not
misleading, or (iii) any untrue statement or alleged untrue statement of any
material fact contained in any Preliminary Prospectus or the Prospectus or any
amendment or supplement thereto, or the omission or alleged omission to state
therein a material fact necessary to make the statements therein, in the light
of the circumstances under which they were made, not misleading, in the case of
subparagraphs (ii) and (iii) of this Section 8(c) to the extent, but only to the
extent, that such untrue statement or alleged untrue statement or omission or
alleged omission was made in reliance upon and in conformity with written
information furnished to the Company by such Underwriter, directly or through
you, specifically for use in the preparation thereof, and agrees to reimburse
the Company and each such Selling Stockholder for any legal or other expenses
reasonably incurred by the Company and each such Selling Stockholder in
connection with investigating or defending any such loss, claim, damage,
liability or action.
 
     The indemnity agreement in this Section 8(c) shall extend upon the same
terms and conditions to, and shall inure to the benefit of, each officer of the
Company who signed the Registration Statement and each director of the Company,
each Selling Stockholder and each person, if any, who controls the Company or
any Selling Stockholder within the meaning of the Act or the Exchange Act.  This
indemnity agreement shall be in addition to any liabilities which each
Underwriter may otherwise have.
 
     (d) Promptly after receipt by an indemnified party under this Section 8 of
notice of the commencement of any action, such indemnified party shall, if a
claim in respect thereof is to be made against any indemnifying party under this
Section 8, notify the indemnifying

                                      -35-
<PAGE>
 
party in writing of the commencement thereof but the omission so to notify the
indemnifying party will not relieve it from any liability which it may have to
any indemnified party otherwise than under this Section 8. In case any such
action is brought against any indemnified party, and it notified the
indemnifying party of the commencement thereof, the indemnifying party will be
entitled to participate therein and, to the extent that it shall elect by
written notice delivered to the indemnified party promptly after receiving the
aforesaid notice from such indemnified party, to assume the defense thereof,
with counsel reasonably satisfactory to such indemnified party; provided,
                                                                --------
however, that if the defendants in any such action include both the
- -------
indemnified party and the indemnifying party and the indemnified party shall
have reasonably concluded that there may be legal defenses available to it
and/or other indemnified parties which are different from or additional to those
available to the indemnifying party, the indemnified party or parties shall have
the right to select separate counsel to assume such legal defenses and to
otherwise participate in the defense of such action on behalf of such
indemnified party or parties. Upon receipt of notice from the indemnifying party
to such indemnified party of the indemnifying party's election so to assume the
defense of such action and approval by the indemnified party of counsel, the
indemnifying party will not be liable to such indemnified party under this
Section 8 for any legal or other expenses subsequently incurred by such
indemnified party in connection with the defense thereof unless (i) the
indemnified party shall have employed separate counsel in accordance with the
proviso to the next preceding sentence (it being understood, however, that the
indemnifying party shall not be liable for the expenses of more than one
separate counsel (together with appropriate local counsel) approved by the
indemnifying party representing all the indemnified parties under Section 8(a),
8(b) or 8(c) hereof who are parties to such action), (ii) the indemnifying party
shall not have employed counsel satisfactory to the indemnified party to
represent the indemnified party within a reasonable time after notice of
commencement of the action or (iii) the indemnifying party has authorized the
employment of counsel for the indemnified party at the expense of the
indemnifying party. In no event shall any indemnifying party be liable in
respect of any amounts paid in settlement of any action unless the indemnifying
party shall have approved the terms of such settlement; provided that such
                                                        --------
consent shall not be unreasonably withheld. No indemnifying party shall,
without the prior written consent of the indemnified party, effect any
settlement of any pending or threatened proceeding in respect of which any
indemnified party is or could have been a party and indemnification could have
been sought hereunder by such indemnified party, unless such settlement includes
an unconditional release of such indemnified party from all liability on all
claims that are the subject matter of such proceeding.
 
     (e) In order to provide for just and equitable contribution in any action
in which a claim for indemnification is made pursuant to this Section 8 but it
is judicially determined (by the entry of a final judgment or decree by a court
of competent jurisdiction and the expiration of time to appeal or the denial of
the last right of appeal) that such indemnification may not be enforced in such
case notwithstanding the fact that this Section 8 provides for indemnification
in such case, all the parties hereto shall contribute to the aggregate losses,
claims, damages or liabilities to which they may be subject (after contribution
from others) in such proportion so that, except as set forth in Section 8(f)
hereof, the Underwriters severally and not jointly are responsible pro rata for
the portion represented by the percentage that the underwriting discount bears
to the initial public offering price, and the Company and the Selling
Stockholders are responsible for the remaining portion, provided, however, that
                                                        --------  -------      
(i) no Underwriter shall be required

                                      -36-
<PAGE>
 
to contribute any amount in excess of the amount by which the underwriting
discount applicable to the Shares purchased by such Underwriter exceeds the
amount of damages which such Underwriter has otherwise been required to pay and
(ii) no person guilty of a fraudulent misrepresentation (within the meaning of
Section 11(f) of the Act) shall be entitled to contribution from any person who
is not guilty of such fraudulent misrepresentation. The contribution agreement
in this Section 8(e) shall extend upon the same terms and conditions to, and
shall inure to the benefit of, each person, if any, who controls any
Underwriter, the Company or any Selling Stockholder within the meaning of the
Act or the Exchange Act and each officer of the Company who signed the
Registration Statement and each director of the Company.
 
     (f) The liability of each Selling Stockholder under the representations,
warranties and agreements contained herein and under the indemnity agreements
contained in the provisions of this Section 8 shall be limited to an amount
equal to the initial public offering price of the Selling Stockholder Shares
sold by such Selling Stockholder to the Underwriters minus the amount of the
underwriting discount paid thereon to the Underwriters by such Selling
Stockholder.  The Company and such Selling Stockholders may agree, as among
themselves and without limiting the rights of the Underwriters under this
Agreement, as to the respective amounts of such liability for which they each
shall be responsible.
 
     (g) The parties to this Agreement hereby acknowledge that they are
sophisticated business persons who were represented by counsel during the
negotiations regarding the provisions hereof including, without limitation, the
provisions of this Section 8, and are fully informed regarding said provisions.
They further acknowledge that the provisions of this Section 8 fairly allocate
the risks in light of the ability of the parties to investigate the Company
and its business in order to assure that adequate disclosure is made in the
Registration Statement and Prospectus as required by the Act and the Exchange
Act.
 
     9.  Representations, Warranties, Covenants and Agreements to Survive
         ----------------------------------------------------------------
Delivery.  All representations, warranties, covenants and agreements of the
- --------                                                                   
Company, the Selling Stockholders and the Underwriters herein or in certificates
delivered pursuant hereto, and the indemnity and contribution agreements
contained in Section 8 hereof shall remain operative and in full force and
effect regardless of any investigation made by or on behalf of any Underwriter
or any person controlling any Underwriter within the meaning of the Act or the
Exchange Act, or by or on behalf of the Company or any Selling Stockholder, or
any of their officers, directors or controlling persons within the meaning of
the Act or the Exchange Act, and shall survive the delivery of the Shares to the
several Underwriters hereunder or termination of this Agreement.
 
     10.  Substitution of Underwriters.  If any Underwriter or Underwriters
          ----------------------------                                     
shall fail to take up and pay for the number of Firm Shares agreed by such
Underwriter or Underwriters to be purchased hereunder upon tender of such Firm
Shares in accordance with the terms hereof, and if the aggregate number of Firm
Shares which such defaulting Underwriter or Underwriters so agreed but failed to
purchase does not exceed 10% of the Firm Shares, the remaining Underwriters
shall be obligated, severally in proportion to their respective commitments
hereunder, to take up and pay for the Firm Shares of such defaulting Underwriter
or Underwriters.

                                      -37-
<PAGE>
 
     If any Underwriter or Underwriters so defaults and the aggregate number of
Firm Shares which such defaulting Underwriter or Underwriters agreed but failed
to take up and pay for exceeds 10% of the Firm Shares, the remaining
Underwriters shall have the right, but shall not be obligated, to take up and
pay for (in such proportions as may be agreed upon among them) the Firm Shares
which the defaulting Underwriter or Underwriters so agreed but failed to
purchase. If such remaining Underwriters do not, at the Closing Date, take up
and pay for the Firm Shares which the defaulting Underwriter or Underwriters so
agreed but failed to purchase, the Closing Date shall be postponed for twenty-
four (24) hours to allow the several Underwriters the privilege of substituting
within twenty-four (24) hours (including non-business hours) another underwriter
or underwriters (which may include any nondefaulting Underwriter) satisfactory
to the Company. If no such underwriter or underwriters shall have been
substituted as aforesaid by such postponed Closing Date, the Closing Date may,
at the option of the Company, be postponed for a further twenty-four (24) hours,
if necessary, to allow the Company the privilege of finding another underwriter
or underwriters, satisfactory to you, to purchase the Firm Shares which the
defaulting Underwriter or Underwriters so agreed but failed to purchase. If it
shall be arranged for the remaining Underwriters or substituted underwriter or
underwriters to take up the Firm Shares of the defaulting Underwriter or
Underwriters as provided in this Section 10, (i) the Company shall have the
right to postpone the time of delivery for a period of not more than seven (7)
full business days, in order to effect whatever changes may thereby be made
necessary in the Registration Statement or the Prospectus, or in any other
documents or arrangements, and the Company agrees promptly to file any
amendments to the Registration Statement, supplements to the Prospectus or other
such documents which may thereby be made necessary, and (ii) the respective
number of Firm Shares to be purchased by the remaining Underwriters and
substituted underwriter or underwriters shall be taken as the basis of their
underwriting obligation. If the remaining Underwriters shall not take up and pay
for all such Firm Shares so agreed to be purchased by the defaulting Underwriter
or Underwriters or substitute another underwriter or underwriters as aforesaid
and the Company shall not find or shall not elect to seek another underwriter or
underwriters for such Firm Shares as aforesaid, then this Agreement shall
terminate.
 
     In the event of any termination of this Agreement pursuant to the preceding
paragraph of this Section 10, neither the Company nor any Selling Stockholder
shall be liable to any Underwriter (except as provided in Sections 5 and 8
hereof) nor shall any Underwriter (other than an Underwriter who shall have
failed, otherwise than for some reason permitted under this Agreement, to
purchase the number of Firm Shares agreed by such Underwriter to be purchased
hereunder, which Underwriter shall remain liable to the Company, the Selling
Stockholders and the other Underwriters for damages, if any, resulting from such
default) be liable to the Company or any Selling Stockholder (except to the
extent provided in Sections 5 and 8 hereof).
 
     The term "Underwriter" in this Agreement shall include any person
substituted for an Underwriter under this Section 10.
 
     11.  Effective Date of this Agreement and Termination.
          ------------------------------------------------ 
 
     (a) This Agreement shall become effective at the earlier of (i) 6:30 A.M.,
San Francisco time, on the first full business day following the effective date
of the

                                      -38-
<PAGE>
 
Registration Statement, or (ii) the time of the initial public offering
of any of the Shares by the Underwriters after the Registration Statement
becomes effective.  The time of the initial public offering shall mean the time
of the release by you, for publication, of the first newspaper advertisement
relating to the Shares, or the time at which the Shares are first generally
offered by the Underwriters to the public by letter, telephone, telegram or
telecopy, whichever shall first occur.  By giving notice as set forth in Section
12 before the time this Agreement becomes effective, you, as Representatives of
the several Underwriters, or the Company, may prevent this Agreement from
becoming effective without liability of any party to any other party, except as
provided in Sections 4(i), 5 and 8 hereof.
 
     (b) You, as Representatives of the several Underwriters, shall have the
right to terminate this Agreement by giving notice as hereinafter specified at
any time on or prior to the Closing Date or on or prior to any later date on
which Option Shares are to be purchased, as the case may be, (i) if the Company
or any Selling Stockholder shall have failed, refused or been unable to perform
any agreement on its part to be performed, or because any other condition of the
Underwriters' obligations hereunder required to be fulfilled is not fulfilled,
including, without limitation, any change in the condition (financial or
otherwise), earnings, operations, business or business prospects of the Company
and its subsidiaries considered as one enterprise from that set forth in the
Registration Statement or Prospectus, which, in your sole judgment, is material
and adverse, or (ii) if additional material governmental restrictions, not in
force and effect on the date hereof, shall have been imposed upon trading in
securities generally or minimum or maximum prices shall have been generally
established on the New York Stock Exchange or on the American Stock Exchange or
in the over the counter market by the NASD, or trading in securities generally
shall have been suspended on either such exchange or in the over the counter
market by the NASD, or if a banking moratorium shall have been declared by
federal, New York or California authorities, or (iii) if the Company shall have
sustained a loss by strike, fire, flood, earthquake, accident or other calamity
of such character as to interfere materially with the conduct of the business
and operations of the Company regardless of whether or not such loss shall have
been insured, or (iv) if there shall have been a material adverse change in the
general political or economic conditions or financial markets as in your
reasonable judgment makes it inadvisable or impracticable to proceed with the
offering, sale and delivery of the Shares, or (v) if there shall have been an
outbreak or escalation of hostilities or of any other insurrection or armed
conflict or the declaration by the United States of a national emergency which,
in the reasonable opinion of the Representatives, makes it impracticable or
inadvisable to proceed with the public offering of the Shares as contemplated by
the Prospectus. In the event of termination pursuant to subparagraph (i) above,
the Company shall remain obligated to pay costs and expenses pursuant to
Sections 4(i), 5 and 8 hereof. Any termination pursuant to any of subparagraphs
(ii) through (v) above shall be without liability of any party to any other
party except as provided in Sections 5 and 8 hereof.
 
     If you elect to prevent this Agreement from becoming effective or to
terminate this Agreement as provided in this Section 11, you shall promptly
notify the Company and the Attorneys by telephone, telecopy or telegram, in each
case confirmed by letter.  If the Company shall elect to prevent this Agreement
from becoming effective, the Company shall promptly notify you by telephone,
telecopy or telegram, in each case, confirmed by letter.

                                      -39-
<PAGE>
 
     12.  Notices.  All notices or communications hereunder, except as herein
          -------                                                            
otherwise specifically provided, shall be in writing and if sent to you shall be
mailed, delivered, telegraphed (and confirmed by letter) or telecopied (and
confirmed by letter) to you c/o BancAmerica Robertson Stephens, 555 California
Street, Suite 2600, San Francisco, California 94104, telecopier number (415)
781-0278, Attention:  General Counsel; if sent to the Company, such notice shall
be mailed, delivered, telegraphed (and confirmed by letter) or telecopied (and
confirmed by letter) to ABIOMED, Inc., 33 Cherry Hill Drive, Danvers,
Massachusetts 01923, telecopier number (978) 777-8411, Attention Chief Financial
Officer; if sent to one or more of the Selling Stockholders, such notice shall
be sent mailed, delivered, telegraphed (and confirmed by letter) or telecopied
(and confirmed by letter) to David M. Lederman and John F. Thero, as Attorneys-
in-Fact for the Selling Stockholders, at ABIOMED, Inc., 33 Cherry Hill Drive,
Danvers, Massachusetts 01923, telecopier number (978) 777-8411, Attention David
M. Lederman and John F. Thero.
 
     13.  Parties.  This Agreement shall inure to the benefit of and be binding
          -------                                                              
upon the several Underwriters and the Company and the Selling Stockholders and
their respective executors, administrators, successors and assigns.  Nothing
expressed or mentioned in this Agreement is intended or shall be construed to
give any person or entity, other than the parties hereto and their respective
executors, administrators, successors and assigns, and the controlling persons
within the meaning of the Act or the Exchange Act, officers and directors
referred to in Section 8 hereof, any legal or equitable right, remedy or claim
in respect of this Agreement or any provisions herein contained, this Agreement
and all conditions and provisions hereof being intended to be and being for the
sole and exclusive benefit of the parties hereto and their respective executors,
administrators, successors and assigns and said controlling persons and said
officers and directors, and for the benefit of no other person or entity. No
purchaser of any of the Shares from any Underwriter shall be construed a
successor or assign by reason merely of such purchase.
 
     In all dealings with the Company and the Selling Stockholders under this
Agreement, you shall act on behalf of each of the several Underwriters, and the
Company and the Selling Stockholders shall be entitled to act and rely upon any
statement, request, notice or agreement made or given by you jointly or by
BancAmerica Robertson Stephens on behalf of you.
 
     14.  Applicable Law.  This Agreement shall be governed by, and construed in
          --------------                                                        
accordance with, the laws of the State of California.
 
     15.  Counterparts.  This Agreement may be signed in several counterparts,
          ------------                                                        
each of which will constitute an original.
 
                 [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

                                      -40-
<PAGE>
 
     If the foregoing correctly sets forth the understanding among the Company,
the Selling Stockholders and the several Underwriters, please so indicate in the
space provided below for that purpose, whereupon this letter shall constitute a
binding agreement among the Company, the Selling Stockholders and the several
Underwriters.
 
                              Very truly yours,
 
                              ABIOMED, INC.
 
 
                              By ---------------------------------------
                                 Name:
                                 Title:
 
                              SELLING STOCKHOLDERS
 
 
                              By ---------------------------------------
                                 Attorney-in-Fact for the Selling Stockholders
                                 named in Schedule B hereto
                                          ----------       
 
 
Accepted as of the date first above written:
 
BANCAMERICA ROBERTSON STEPHENS
UBS SECURITIES LLC
On their behalf and on behalf of each of the
several Underwriters named in Schedule A
hereto.
 
 
By BANCAMERICA ROBERTSON STEPHENS
 
 
By ---------------------------------------
          Authorized Signatory
 

                                      -41-
<PAGE>
 
                                  SCHEDULE A
                                        
                                                      Number of Firm
                                                       Shares to Be
Underwriters                                            Purchased
- ------------                                          --------------
 
BancAmerica Robertson Stephens...................
UBS Securities LLC...............................
[OTHERS]
 
                                                      -------------
   TOTAL.........................................       2,400,000
                                                      =============


 

<PAGE>
 
                                    SCHEDULE B

<TABLE> 
<CAPTION> 
                                                      Number of Company
                                                        Shares to Be
                                                          Purchased
                                                      -----------------
<S>                                                  <C>  
 
ABIOMED, Inc.....................................         2,250,000
                                                          ---------
TOTAL............................................         2,250,000
                                                          =========
 

                                                      Number of Selling
                                                      Stockholder Shares
Selling Stockholders                                   To Be Purchased
- --------------------                                  ------------------
 
David M. Lederman................................           115,000
Robert T.V. Kung.................................            35,000
                                                          ---------
TOTAL............................................           150,000
                                                          =========
 
 
 
   TOTAL.........................................         2,400,000
                                                          =========
</TABLE> 
                                      -2-

<PAGE>
 
                                                                   EXHIBIT 23.1
 
                   CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS
   
As independent public accountants, we hereby consent to the inclusion in this
registration statement on Form S-3 (File No. 333-36657) of our report dated
May 8, 1997 and to all references to our Firm included in or made a part of
this registration statement.     
 
                                          ARTHUR ANDERSEN LLP

    
Boston, MA
October 10, 1997     

<PAGE>
 
                                  EXHIBIT 24.1
 
                                   SIGNATURES
 
  PURSUANT TO THE REQUIREMENTS OF THE SECURITIES ACT OF 1933, THE REGISTRANT
CERTIFIES THAT IT HAS REASONABLE GROUNDS TO BELIEVE THAT IT MEETS ALL OF THE
REQUIREMENTS FOR FILING ON FORM S-3 AND HAS DULY CAUSED THIS REGISTRATION
STATEMENT TO BE SIGNED ON ITS BEHALF BY THE UNDERSIGNED, THEREUNTO DULY
AUTHORIZED, IN THE CITY OF BOSTON, COMMONWEALTH OF MASSACHUSETTS, ON SEPTEMBER
29, 1997.
 
                                         ABIOMED, Inc.
 
                                         By: __________________________________
                                             DR. DAVID M. LEDERMANPRESIDENT
                                              AND CHIEF EXECUTIVE OFFICER
 
                               POWER OF ATTORNEY
 
  KNOW ALL MEN BY THESE PRESENTS, that each person whose signature appears
below constitutes and appoints Dr. David M. Lederman and John. F. Thero his
true and lawful attorneys-in-fact and agents, with full power of substitution
and resubstitution, for him and in his name, place and stead, in any and all
capacities, to sign any or all amendments (including post-effective amendments)
to this Registration Statement, and to file the same, with all exhibits thereto
and other documents in connection therewith, and, in connection with any
registration of additional securities pursuant to Rule 462(b) under the
Securities Act of 1933, as amended, to sign any abbreviated registration
statement and any and all amendments thereto, and to file the same, with all
exhibits thereto and other documents in connection therewith, in each case,
with the Securities and Exchange Commission, granting unto said attorneys-in-
fact and agents, and each of them, full power and authority to do and perform
each and every act and thing requisite and necessary to be done in and about
the premises, as fully to all intents and purposes as he might or could do in
person, hereby ratifying and confirming all that said attorneys-in-fact and
agents, or any of them, or their substitutes, may lawfully do or cause to be
done by virtue hereof.
 
  PURSUANT TO THE REQUIREMENTS OF THE SECURITIES ACT OF 1933, THIS REGISTRATION
STATEMENT HAS BEEN SIGNED BY THE FOLLOWING PERSONS IN THE CAPACITIES AND ON THE
DATES INDICATED.
 
             SIGNATURE                       TITLE                 DATE
 
- ------------------------------------  Chief Executive          September  ,
         DAVID M. LEDERMAN             Officer, President          1997
                                       and Director
                                       (Principal
                                       Executive Officer)
 
- ------------------------------------  Chief Financial          September  ,
           JOHN F. THERO               Officer, Vice               1997
                                       President--Finance
                                       and Treasurer
                                       (Principal Financial
                                       and Accounting
                                       Officer)
<PAGE>
 
             SIGNATURE                       TITLE                 DATE
 
- ------------------------------------  Director                 September  ,
     DESMOND H. O'CONNELL, JR.                                     1997
 
        /s/ John F. O'Brien           Director                September 29,
- ------------------------------------                               1997
          JOHN F. O'BRIEN
 
- ------------------------------------  Director                 September  ,
          HENRI A. TERMEER                                         1997
 
                                      Director                 September  ,
- ------------------------------------                               1997
          W. GERALD AUSTEN
 
                                      Director                 September  ,
- ------------------------------------                               1997
            PAUL FIREMAN

<PAGE>
                                                                    EXHIBIT 99.1


 
                        Name: _________________________


                         SELLING STOCKHOLDER AGREEMENT
                         -----------------------------


    AGREEMENT, dated as of October __, 1997 (the "Agreement"), among ABIOMED,
Inc., a Delaware corporation (the "Company"), and each stockholder of the
Company listed on Exhibit A, attached hereto (collectively the "Selling
Stockholders").

                              W I T N E S S E T H:
                              ------------------- 

    WHEREAS, the Board of Directors of the Company has determined that a public
offering (the "Public Offering") of the Company's Common Stock, $.01 par value
(the "Common Stock"), would be beneficial to the Company and its stockholders
and proposes to issue shares of Common Stock (the "Company Shares") for such
purpose; and

    WHEREAS, the Company also has determined that it would be beneficial to the
Company and its stockholders for certain stockholders to have the opportunity to
sell in the Public Offering a portion of the shares of Common Stock held by such
stockholders; and

    WHEREAS, the Company has offered such stockholders such opportunity and the
Selling Stockholders propose to accept such offer and sell in the Public
Offering an aggregate of up to _____ shares of Common Stock (the "Stockholder
Shares").

    NOW THEREFORE, in consideration of the premises and the mutual and dependent
promises hereinafter set forth and such other good and valuable consideration,
the receipt and sufficiency of which is hereby acknowledged, the parties hereto
agree as follows:

    SECTION 1.  Payment of Expenses.
                ------------------- 

         (a) The Company shall pay (i) all of the expenses, other than
underwriting discounts, incurred in connection with the Public Offering
(including, but not limited to, all registration, filing and qualification fees,
transfer agent's fees, printing and engraving fees and legal and accounting
fees), and (ii) the Company's pro rata portion of all underwriting discounts
incurred in connection with the Public Offering, determined in accordance with
the number of Company Shares and Stockholder Shares actually sold by each
respective party in the Public Offering.

         (b) Each Selling Stockholder shall pay such Selling Stockholder's pro
rata portion of all underwriting discounts incurred in connection with the
Public Offering, determined in accordance with the number of Company Shares and
Stockholder Shares actually sold by each respective party in the Public
Offering.

                                      -1-
<PAGE>
 
    SECTION 2.  Indemnification; Contribution.
                ----------------------------- 

         (a) The Company shall indemnify each of the Selling Stockholders, and
each person (if any) who controls such Selling Stockholder within the meaning of
Section 15 of the Securities Act of 1933, as amended (the "Act"), against all
losses, claims, damages and liabilities and expense (including all reasonable
fees and disbursements of counsel incurred in defending against any such claim,
damage or liability) caused by any untrue statement or alleged untrue statement
of a material fact contained in the registration statement filed or to be filed
with the Securities and Exchange Commission (the "Commission"), in connection
with the Public Offering, as the same may be amended or supplemented from time
to time (the "Registration Statement") or in any prospectus filed with, or
delivered to, the Commission in connection with the Public Offering, or caused
by any omission or alleged omission therefrom of a material fact required to be
stated therein or necessary to make the statements therein, in the light of the
circumstances in which they were made, not misleading; provided, however,
                                                       --------  ------- 
insofar as such losses, claims, damages, or liabilities are caused by an untrue
statement of a material fact contained in, or any material fact omitted from,
information relating to a Selling Stockholder furnished in writing to the
Company by such Selling Stockholder, in his capacity as Selling Stockholder, for
use in the Registration Statement or any amendment or supplement thereto, or any
such prospectus, then the Company shall have no obligation hereunder to
indemnify the Selling Stockholder furnishing such information.  For purposes
hereof, such information shall be deemed to be the information provided to the
Company by such Selling Stockholder pursuant to such Selling Stockholder's
Questionnaire for Directors, Officers and Certain other Persons.

         (b) Each Selling Stockholder shall indemnify each of the Company and
the other Selling Stockholders, and each person (if any) who controls the
Company or such other Selling Stockholder within the meaning of Section 15 of
the Act against all losses, claims, damages and liabilities and expense
(including all reasonable fees and disbursements of counsel incurred in
defending against any such claim, damage or liability) caused by any untrue
statement or alleged untrue statement of a material fact contained in the
Registration Statement or in any prospectus filed with, or delivered to, the
Commission in connection with the Public Offering, or caused by any omission or
alleged omission therefrom of a material fact required to be stated therein or
necessary to make the statements therein, in the light of the circumstances in
which they were made, not misleading, but only with respect to information
relating to such Selling Stockholder furnished in writing by or on behalf of
such Selling Stockholder expressly for use in the Registration Statement or any
amendment or supplement thereto, or any such prospectus, provided, however, no
                                                         --------  -------    
Selling Stockholder shall be liable in an amount that exceeds the aggregate
initial public offering price of the Stockholder Shares sold by the Selling
Stockholder, net of the underwriting discount.

         (c) The indemnity agreements of the Company and the Selling
Stockholders contained in this Section 2 shall remain operative and in full
force and effect regardless of any investigation made by or on behalf of any
indemnified party and shall survive delivery of shares of Common Stock pursuant
to the Public Offering.

                                      -2-
<PAGE>
 
         (d) In order to provide for just and equitable contribution in
circumstances in which indemnification provided for in paragraph (a) of this
Section 2 is unavailable, the Company and each of the Selling Stockholders shall
contribute to the aggregate losses, claims, damages, liabilities and expenses
(including all reasonable fees and disbursements of counsel incurred in
defending against any claim, damage, or liability), to which one or more of the
Selling Stockholders may be subject in such proportion as is appropriate to
reflect the relevant fault of the Company and the respective Selling
Stockholders in connection with the statements or omissions that resulted in
such losses, claims, damages, liabilities and expenses as well as any other
relevant equitable considerations; provided, however, that:
                                   -----------------       

               (i)   in any case where any Selling Stockholder is seeking
contribution hereunder such Selling Stockholder shall be entitled to
contribution from the remaining Selling Stockholders pursuant to this Agreement
only after first seeking contribution from the Company;

               (ii)  no Selling Stockholder shall in any case be required to
contribute or make any payments under this paragraph (d) which in the aggregate
exceed his pro rata share of such losses, claims, damages, liabilities and
expenses determined in accordance with the total number of Company Shares and
Stockholder Shares sold by each respective party hereto provided, however, that,
                                                        --------  -------       
except as set forth in subparagraph (iii) of this paragraph (d), no Selling
Stockholder shall be liable to contribute an amount that exceeds the aggregate
public offering price of the Stockholder Shares sold by the Selling Stockholder,
net of the underwriting discount;

               (iii) in the event the Company or any Selling Stockholder
defaults on its obligation to make any contribution pursuant to this paragraph
(d), the amount by which each of the remaining parties is obligated to
contribute hereunder shall be increased in accordance with the relation of the
number of shares of Common Stock being sold by each such remaining party to the
aggregate number of shares of Common Stock being sold by all such remaining
parties;

               (iv)  neither the Company nor any Selling Stockholder will be
required to make any contribution to another Selling Stockholder with respect to
matters for which the other Selling Stockholder would not otherwise be entitled
to be indemnified under paragraph (a) of this Section 2 had such indemnification
been available; and

               (v)   for purposes of this paragraph (d), each person, if any,
who controls a Selling Stockholder within the meaning of Section 15 of the Act,
and each director, officer or partner (if any) of such Selling Stockholder,
shall have the same rights to contribution under this Agreement as such Selling
Stockholder.

                                      -3-
<PAGE>
 
    SECTION 3.  Governing Law.
                ------------- 

    This Agreement shall be governed by and construed in accordance with the
laws of the State of Delaware.


    SECTION 4.  Invalidity.
                ---------- 

    If any provision of this Agreement shall be determined by a court of
competent jurisdiction to be invalid or unenforceable, such determination shall
not affect the remaining provisions of the Agreement, all of which shall remain
in full force and effect.


    SECTION 5.  Counterparts.
                ------------ 

    This Agreement may be executed in any number of counterparts, each of which
shall be deemed to be an original and all of which together shall be deemed to
be one and the same instrument.


    SECTION 6.  Notices.
                ------- 

    Any notice given pursuant to this Agreement shall be sent by certified mail,
return receipt requested, to the address set forth under each party's name on
the signature page of this Agreement, or to such other address as may be
designated by notice given to each party pursuant to the provisions hereof.


    SECTION 7.  Headings.
                -------- 

    The headings contained in this Agreement are for descriptive purposes only
and shall not be given substantive effect.

                           [Signature Page to Follow]

                                      -4-
<PAGE>
 
    IN WITNESS WHEREOF, each of the parties hereto has executed this Agreement
under seal as of the day and year first written above.

                             ABIOMED, INC., a Delaware corporation


                             By:
                                ----------------------------------------
                                John F. Thero, Vice President - Finance
                                Chief Financial Officer, Treasurer and
                                Assistant Secretary


                             SELLING STOCKHOLDER

                             -------------------------------

                             Address:
 
                             -------------------------------
                             -------------------------------
                             -------------------------------

                                      -5-
<PAGE>
 
                                   EXHIBIT A
                                        
                              SELLING STOCKHOLDERS


David M. Lederman
Robert T.V. Kung
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

                                      -6-


© 2022 IncJournal is not affiliated with or endorsed by the U.S. Securities and Exchange Commission