<PAGE>

                                     AMENDMENT

                                         TO

                            LOAN AND SECURITY AGREEMENT


     This Amendment to Loan and Security Agreement (this "Amendment") is entered
into as of October 12, 1998, by and between SILICON VALLEY BANK ("Bank") and
HEARTPORT, INC. ("Borrower").

                                       RECITALS

     Borrower and Bank are parties to that certain Amended and Restated Loan and
Security Agreement dated as of March 20, 1998, as amended from time to time (the
"Loan Agreement").  The Agency Agreement has been terminated and BNP is no
longer a participant in the Loan Agreement.  All references in the Loan
Documents to "Bank" or "Banks" shall mean SVB.  The parties desire to amend the
Loan Agreement in accordance with the terms of this Amendment.  

          NOW, THEREFORE, the parties agree as follows:
     
          1.   All references in the Loan Agreement and the Loan Documents to
"Bank" or "Banks" shall mean SVB.
     
          2.   Certain defined terms in Section 1.1 of the Loan Agreement are
hereby added or amended as follows:
          
               "Advance" or "Advances" means a cash advance or cash advances
     under the Revolving Facility.

               "Agency Agreement" means an agency agreement, if any, between any
     bank or lender and the Servicing Agent, concerning the administration of
     the Loan Agreement by them.

               "Committed Line" means Ten Million Dollars ($10,000,000).

               "Debt Service Coverage" means, as measured quarterly as of the
     last day of each fiscal quarter of Borrower, on a consolidated basis
     determined in accordance with GAAP, the ratio of (a) an amount equal to the
     sum of (i) net income, PLUS (ii) depreciation, amortization of intangible
     assets and other non-cash charges to income, and (iii) accrued interest, to
     (b) an amount equal to the sum of all scheduled repayments and mandatory
     prepayments of principal on account of long-term debt for such quarter (or
     month, as applicable), including accrued interest.

               "Foreign Exchange Reserve" has the meaning set forth in
     Section 2.1.2 herein.

                                      1

<PAGE>

               "Intellectual Property Spin-Out" means the disposal (including
     through lease, license, or assignment) to one or more entities of Non-Core
     Intellectual Property Rights in consideration of the issue of equity
     interests in such entities and/or royalty payments from such entities.

               "Issuing Bank" means SVB.

               "Non-Core Intellectual Property Rights" means the intellectual
     property rights of the Borrower related to (i) "Maze" procedures or
     surgical treatment of atrial fibrillation (ii) endovascular valve
     replacement, and (iii) organ specific drug delivery systems.

               "Percentage Share" means, with respect to SVB, 100%.

               "Repurchase Transactions" means the entering into and performance
     of "repurchase" transactions prior to June 30, 1999, between the Borrower
     and Morgan Stanley and similar counterparties in an aggregate net amount
     (exclusive of finance charges) not to exceed $25,000,000.

               "Subordinated Debt Purchases" means the repurchase prior to June
     30, 1999, of outstanding convertible subordinated notes of the Borrower due
     in the year 2004, in an aggregate purchase price not to exceed $25,000,000.
     
          3.   The definition of "Permitted Indebtedness" is hereby amended by
adding the following new subparagraph (k):
     
               "(k) Indebtedness incurred as a result of Borrower's entering
     into Repurchase Transactions pursuant to repurchase agreements."
     
          4.   The definition of "Permitted Investments" is hereby amended by
adding the following new subparagraph (o): 
     
               "(o) Investments consisting of equity holdings in entities
     acquiring Non-Core Intellectual Property Rights pursuant to an Intellectual
     Property Spin-Out."
     
          5.   The definition of "Permitted Lien" is hereby amended by adding
the following new subparagraph (i):
     
               "(i) Liens in respect of Permitted Investments arising by virtue
of Repurchase Transactions."
     
          6.   The first paragraph of Section 2.1 is hereby amended and replaced
in its entirety as follows:
     
               "ADVANCES.  Subject to and upon the terms and conditions of this
     Agreement, Bank agrees to make Advances to Borrower under the Revolving
     Facility in an aggregate amount not to exceed the Committed Line MINUS: 
     (i) the face amount of all outstanding Letters of Credit issued as a
     sublimit under the Revolving Facility (including drawn but unreimbursed
     Letters of Credit), and (ii) the Foreign Exchange Reserve.  Subject to the
     terms and conditions of this Agreement, amounts borrowed pursuant to this
     Section 2.1 may be repaid and reborrowed at any time prior to the Maturity
     Date."

                                      2

<PAGE>
     
          7.   Section 2.1(c) is hereby amended and replaced in its
     entirety as follows:
     
               "(c) LIBOR RATE ADVANCES.  Each LIBOR Rate Advance shall be in an
     amount of not less than Five Hundred Thousand Dollars ($500,000).  The
     outstanding principal balance of each LIBOR Rate Advance shall bear
     interest until principal is due (computed daily on the basis of a 360 day
     year and actual days elapsed) at a rate per annum equal to the LIBOR Rate
     plus 250 basis points for such LIBOR Rate Advance.  The entire outstanding
     principal amount of each LIBOR Rate Advance shall be due and payable on the
     last day of the Interest Period for such LIBOR Rate Advance and in any
     event on the Maturity Date."
     
          8.   The first sentence of Section 2.1.1(c) is hereby amended and
replaced in its entirety as follows:
     
               "Subject to the terms and conditions of this Agreement, Bank
     agrees to issue or cause to be issued letters of credit (each a "Letter of
     Credit," collectively, the "Letters of Credit") for the account of Borrower
     in an aggregate outstanding face amount not to exceed (i) the Committed
     Line, MINUS (ii) the then outstanding principal balance of the Advances
     under the Revolving Facility (including drawn but unreimbursed Letters of
     Credit issued as a sublimit under the Revolving Facility), MINUS (iii) the
     Foreign Exchange Reserve; provided that the face amount of outstanding
     Letters of Credit (including drawn but unreimbursed letters of Credit)
     shall not exceed Five Million Dollars ($5,000,000)."

          9.   A new Section 2.1.2 is hereby added as follows:
     
               "2.1.2    FOREIGN EXCHANGE CONTRACT; FOREIGN EXCHANGE
     SETTLEMENTS.   Subject to the terms of this Agreement, Borrower may enter
     into foreign exchange contracts (the "Exchange Contracts") under the
     Revolving Facility not to exceed an aggregate amount of One Million Dollars
     ($1,000,000) (the "Contract Limit"), pursuant to which Bank shall sell to
     or purchase from Borrower foreign currency on a spot or future basis. 
     Borrower shall not request any Exchange Contracts at any time it is out of
     compliance with any of the provisions of this Agreement.  All Exchange
     Contracts must provide for delivery of settlement on or before the Maturity
     Date.  The amount available under the Committed Line at any time shall be
     reduced by the following amounts (the "Foreign Exchange Reserve") on any
     given day (the "Determination Date"):  (i) on all outstanding Exchange
     Contracts on which delivery is to be effected or settlement allowed more
     than two business days after the Determination Date, ten percent (10%) of
     the gross amount of the Exchange Contracts; plus (ii) on all outstanding
     Exchange Contracts on which delivery is to be effected or settlement
     allowed within two (2) business days after the Determination Date, one
     hundred percent (100%) of the gross amount of the Exchange Contracts."
     
          10.  Section 4 is hereby amended and replaced in its entirety as
     follows:
     
               "4.  CREATION OF SECURITY INTEREST

                                      3

<PAGE>

               4.1  GRANT OF SECURITY INTEREST.  Borrower grants and pledges to
     Bank a continuing security interest in all presently existing and hereafter
     acquired or arising Collateral in order to secure prompt repayment of any
     and all Obligations and in order to secure prompt performance by Borrower
     of each of its covenants and duties under the Loan Documents.  Except as
     set forth in the Schedule and any Permitted Liens, such security interest
     constitutes a valid, first priority security interest in the presently
     existing Collateral, and will constitute a valid, first priority security
     interest in Collateral acquired after the date hereof.
     
               4.2  DELIVERY OF ADDITIONAL DOCUMENTATION REQUIRED.  Borrower
     shall from time to time execute and deliver to Bank, at the request of
     Bank, all Negotiable Collateral, all financing statements and other
     documents that Bank may reasonably request, in form satisfactory to Bank,
     to perfect and continue perfected Bank's security interests in the
     Collateral and in order to fully consummate all of the transactions
     contemplated under the Loan Documents.
     
               4.3  RIGHT TO INSPECT.  Bank (through any of its officers,
     employees, or agents) shall have the right, upon reasonable prior notice,
     from time to time during Borrower's usual business hours, to inspect
     Borrower's Books and to make copies thereof and to check, test, and
     appraise the Collateral in order to verify Borrower's financial condition
     or the amount, condition of, or any other matter relating to, the
     Collateral.
     
               4.4  REQUIREMENT FOR CASH COLLATERAL.  If Borrower does not
     comply with any covenant contained in  Sections 6.7, 6.8 or 6.9 herein,
     then Borrower shall pledge cash or a certificate of deposit to Servicing
     Agent in an amount equal to one hundred five percent (105%) of the
     aggregate amount without duplication of (i) all the outstanding Advances
     and (ii) all outstanding Letters of Credit, in each case to the extent not
     already cash-secured.  Servicing Agent agrees to release the cash pledged
     pursuant to this Section 4.4 upon Borrower's achieving compliance with the
     covenant giving rise to the pledge hereunder.  Notwithstanding anything to
     the contrary in this Agreement, failure to comply with any such
     covenant shall not be a default or an Event of Default so long as the
     Borrower complies with this Section 4.4 on the next Business Day after the
     Borrower becomes aware of the noncompliance with any such covenant."
     
          11.  Section 6.3(b) is hereby amended and replaced in its
     entirety as follows:
     
               "(b) Borrower shall deliver to Bank a company prepared
     consolidated balance sheet and income statement covering Borrower's
     consolidated operations for the relevant month, certified by a 
     Responsible Officer within thirty (30) days after the last day of 
     each calendar month."

          12.  Section 6.7 is hereby amended and restated in its entirety as
follows:

               "6.7 DEBT-NET WORTH RATIO.  Borrower shall maintain, as of the
     last day of each of calendar month, a ratio of Total Liabilities to
     Tangible Net Worth of not more than 1.75 to 1.00."
    
                                      4

<PAGE>

          13.  Section 6.8 is hereby amended and restated in its entirety
     as follows:
     
               "6.8 TANGIBLE NET WORTH.  Borrower shall maintain, as of the last
     day of each calendar month, a Tangible Net Worth of not less than Twenty
     Million Dollars ($20,000,000)."  
     
     
          14.  Section 6.9 is hereby amended and restated in its entirety
     as follows:
     
               "6.9 MINIMUM LIQUIDITY; DEBT SERVICE COVERAGE.  Subject to the
     following sentence, Borrower shall maintain, as of the last day of each of
     month, a minimum Liquidity of the greater of (a) one and three quarters
     (1.75) times the amount of outstanding obligations hereunder OR (b) an
     amount equal to six (6) times the then applicable Remaining Months
     Liquidity.   Notwithstanding the foregoing, from and after the time
     Borrower achieves a Debt Service Coverage of at least 1.50 to 1.00 for two
     (2) consecutive fiscal quarters, Borrower shall not be subject to the
     Minimum Liquidity requirements set forth in this Section 6.9, but instead
     shall be required to maintain a Debt Service Coverage of at least 1.50 to
     1.00 for each fiscal quarter thereafter."
     
          15.  Section 7.1 is hereby amended and restated in its entirety
     as follows:
     
               "7.1 DISPOSITIONS.  Convey, sell, lease, transfer or otherwise
     dispose of (collectively a "Transfer"), or permit any of its Subsidiaries
     to transfer, all or any part of its business or property other than; (i)
     Transfers of Inventory and other assets in the ordinary course of business;
     (ii) Transfers of non-exclusive licenses and similar arrangements for the
     use of the property of the Borrower or its Subsidiaries and exclusive and
     non-exclusive licenses entered into in good faith in connection with the
     distribution of the Borrower's and its Subsidiaries' products; (iii)
     Transfers of worn-out or obsolete Equipment; (iv) Transfers pursuant to an
     Intellectual Property Spin-Out; or (v) Transfers of Permitted Investments
     in the ordinary course of business or pursuant to a Repurchase Transaction,
     and in accordance with this Agreement."
     
          16.  Section 7.6 is hereby amended and restated in its entirety
     as follows:
     
               "7.6 DISTRIBUTIONS.  Pay any dividends or make any other
     distribution or payment on account of or in redemption, retirement or
     purchase of any capital stock, except (i) repurchases from current or
     former employees, directors or consultants of the Borrower under the terms
     of any stock option or stock purchase plans or agreements up to a maximum
     of $500,000 in any one fiscal year (provided an Event of Default has not
     occurred and is continuing at the time of such repurchase or would exist
     after giving effect to such repurchase), and (ii) dividends payable solely
     in common stock."

          17.  Section 7.9 is hereby amended and restated in its entirety
     as follows:

               "7.9 SUBORDINATED DEBT AND SUBORDINATED DEBT PURCHASES.  Make
     any payment in respect of any Subordinated Debt or Subordinated Debt
     Purchases, or permit any of its Subsidiaries to 

                                      5

<PAGE>

     make any such payment, except in compliance with the terms of such 
     Subordinated Debt or Subordinated Debt Purchases and this Agreement, or 
     amend any provision contained in any documentation relating to the 
     Subordinated Debt or Subordinated Debt Purchases."

          18.  Section 8.7 is hereby amended and restated in its entirety
     as follows:

               "8.7 SUBORDINATED DEBT AND SUBORDINATED DEBT PURCHASES.     If
     Borrower makes any payment on account of Subordinated Debt, except to the
     extent such payment is allowed under any subordination agreement entered
     into with the Banks or pursuant to Subordinated Debt Purchases."

          19.  The reference in Section 10 to BNP and the requirement of
delivery of notices to BNP is hereby deleted in its entirety.
     
          20.  Exhibit C is hereby replaced in its entirety with the attached
Exhibit C.
     
          21.  Borrower reaffirms all the terms and conditions in the Negative
Pledge Agreement dated as of March 20, 1998.
     
          22.  As a condition to the effectiveness of this Amendment, Borrower
shall pay all Bank Expenses (including reasonable attorneys' fees) incurred
through the date of this Amendment, which fees and expenses become nonrefundable
and fully earned on the date hereof.
     
          23.  The obligation of Bank to make any further Advance pursuant to
the terms of the Agreement, as amended hereby, is subject to the condition
precedent that Bank shall have received, in form and substance satisfactory to
Bank, the following:
     
               a.   this Amendment, duly executed by the Borrower;
     
               b.   a certificate of secretary of the Borrower with respect
     to incumbency and resolutions authorizing the execution and delivery
     of this Amendment;
     
               c.   payment of the Bank Expenses then due as specified in
     Section 13 hereof; 
     
               d.   financing statements as Bank may require; and
     
               d.   such other documents, and completion of such other
     matters, as Bank may reasonably deem necessary or appropriate.
     
          24.  Unless otherwise defined, all capitalized terms in this Amendment
shall be as defined in the Agreement.  Except as amended, the Loan Agreement
remains in full force and effect.

                                      6

<PAGE>
     
          25.  Borrower represents and warrants that the Representations and
Warranties contained in the Agreement are true and correct as of the date of
this Amendment, and that no Event of Default has occurred and is continuing.
     
          26.  This Amendment may be executed in two or more counterparts, each
of which shall be deemed an original, but all of which together shall constitute
one instrument.
     
          IN WITNESS WHEREOF, the undersigned have executed this Amendment
     as of the first date above written.
     
                                       HEARTPORT, INC.
     
                                       By: /s/ Rebecca Kuhn
                                           -----------------------------------
     
                                       Title:  Treasurer
                                             ---------------------------------
     
                                       SILICON VALLEY BANK
     
                                       By:  /s/ Lois M. Fisher
                                           -----------------------------------
     
                                       Title: Sr. Vice President
                                             ---------------------------------
  
                                      7

<PAGE>

                                   EXHIBIT C
                                COMPLIANCE CERTIFICATE

TO:       SILICON VALLEY BANK, AS SERVICING AGENT

FROM:     HEARTPORT, INC.

     The undersigned authorized officer of Heartport, Inc. hereby certifies that
in accordance with the terms and conditions of the Amended and Restated Loan and
Security Agreement, dated as of March 20, 1998, as amended, between Borrower and
the Banks named therein (the "Agreement"), (i) Borrower is in complete
compliance for the period ending _________________ with all financial covenants
except as noted below, (ii) all representations and warranties of Borrower
stated in the Agreement are true and correct in all material respects as of the
date hereof, provided however, that those representations and warranties
expressly referring to another date shall be true and complete in all material
respects as of such date, and (iii) he/she is a Responsible Officer under the
Agreement.  Attached herewith are the required documents supporting the above
certification.  The Officer further certifies that these are prepared in
accordance with Generally Accepted Accounting Principles (GAAP) and are
consistently applied from one period to the next except as explained in an
accompanying letter or footnotes.

                                           
PLEASE INDICATE COMPLIANCE STATUS BY CIRCLING YES/NO UNDER "COMPLIES" COLUMN.

<TABLE>
<CAPTION>
     REPORTING COVENANT                 REQUIRED                                COMPLIES
     ------------------                 --------                                --------
     <S>                                <C>                     <C>             <C>
     Monthly financial statements       Monthly within 30 days                  Yes  No
     Annual (CPA Audited)               FYE within 90 days                      Yes  No
     10K & 10Q                          Within 10 days                          Yes  No

<CAPTION>

     FINANCIAL COVENANT                 REQUIRED                 ACTUAL         COMPLIES
     ------------------                 --------                 ------         --------
     Maintain on a Quarterly Basis:
     ------------------------------
     Liquidity/Debt Service Coverage     (1)                     _________      Yes  No 
     Maintain on a Monthly Basis:
     ----------------------------
     Minimum Tangible Net Worth         $20,000,000              $________      Yes  No
     Maximum Debt/Tangible Net Worth    1.75:1.00                _____:1.00     Yes  No
</TABLE>

     (1)    1.75x outstanding obligations or 6x Remaining Months Liquidity
maintained on a monthly basis, converts to Debt Service Coverage 1.50 to 1.00
upon 2 consecutive quarters of Debt Service Coverage of 1.50 to 1.00 which is
maintained on a quarterly basis.

 COMMENTS REGARDING EXCEPTIONS:  See Attached.
----------------------------------------------


 Sincerely,                             

----------------------------------------
 SIGNATURE                              

----------------------------------------
 TITLE                                  

----------------------------------------
 DATE

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


          BANK USE ONLY

 Received by:
              -----------------------
                AUTHORIZED SIGNER

 Date:                               
      -------------------------------

 Verified:
          ---------------------------
                AUTHORIZED SIGNER    

 Date:
       ------------------------------

 Compliance Status:       Yes     No 

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


                                      1

<PAGE>



                          CORPORATE RESOLUTIONS TO BORROW


-------------------------------------------------------------------------------
BORROWER:      HEARTPORT, INC.
-------------------------------------------------------------------------------


     I, the undersigned Secretary or Assistant Secretary of Heartport, Inc. (the
"Corporation"), HEREBY CERTIFY that the Corporation is organized and existing
under and by virtue of the laws of the State of its incorporation.

     I FURTHER CERTIFY that attached hereto as Attachments 1 and 2 are true and
complete copies of the Certificate of Incorporation and Bylaws of the
Corporation, each of which is in full force and effect on the date hereof.

     I FURTHER CERTIFY that at a meeting of the Directors of the Corporation,
duly called and held, at which a quorum was present and voting (or by other duly
authorized corporate action in lieu of a meeting), the following resolutions
were adopted.

     BE IT RESOLVED, that ANY ONE (1) of the following named officers,
employees, or agents of this Corporation, whose actual signatures are shown
below:

<TABLE>
<CAPTION>
     NAMES                    POSITIONS                ACTUAL SIGNATURES
----------------------       -----------------------   -----------------
<S>                           <C>                      <C>

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

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

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

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

----------------------       -----------------------   -----------------
</TABLE>

acting for and on behalf of this Corporation and as its act and deed be, and
they hereby are, authorized and empowered:

     BORROW MONEY.  To borrow from time to time from Silicon Valley Bank
("Bank") and Silicon Valley Bank, as Servicing Agent ("Agent"), on such terms as
may be agreed upon between the officers, employees, or agents and Bank, such sum
or sums of money as in their judgment should be borrowed, without limitation,
including such sums as are specified in that certain Amended and Restated Loan
and Security Agreement dated as of March 20, 1998, as amended, including,
without limitation by the Amendment to Loan and Security Agreement dated as of
October 12, 1998 (the "Loan Agreement").

     EXECUTE NOTES.  To execute and deliver the Loan Agreement and all related
documents to Banks and/or Agent and also to execute and deliver to Lender one or
more renewals, extensions, modifications, refinancings, consolidations, or
substitutions for one or more of the notes, or any portion of the notes.

     GRANT SECURITY.  To grant a security interest to Agent and the Banks in the
Collateral described in the Loan Agreement, which security interest shall secure
all of the Corporation's Obligations, as described in the Loan Agreement.

                                      1

<PAGE>

     LETTERS OF CREDIT; FOREIGN EXCHANGE.  To request that Letters of Credit be
issued, and Foreign Exchange Contacts entered into on behalf of the Corporation,
and to provide reimbursement therefor.

     NEGOTIATE ITEMS.  To draw, endorse, and discount with each Bank all drafts,
trade acceptances, promissory notes, or other evidences of indebtedness payable
to or belonging to the Corporation or in which the Corporation may have an
interest, and either to receive cash for the same or to cause such proceeds to
be credited to the account of the Corporation with Agent, or to cause such other
disposition of the proceeds derived therefrom as they may deem advisable.
     
     FURTHER ACTS.  In the case of lines of credit, to designate additional or
alternate individuals as being authorized to request advances thereunder, and in
all cases, to do and perform such other acts and things, to pay any and all fees
and costs, and to execute and deliver such other documents and agreements as
they may in their discretion deem reasonably necessary or proper in order to
carry into effect the provisions of these Resolutions.

     BE IT FURTHER RESOLVED, that any and all acts authorized pursuant to these
resolutions and performed prior to the passage of these resolutions are hereby
ratified and approved, that these Resolutions shall remain in full force and
effect and Agent and Banks may rely on these Resolutions until written notice of
their revocation shall have been delivered to and received by Agent and Banks. 
Any such notice shall not affect any of the Corporation's agreements or
commitments in effect at the time notice is given.

     I FURTHER CERTIFY that the officers, employees, and agents named above are
duly elected, appointed, or employed by or for the Corporation, as the case may
be, and occupy the positions set forth opposite their respective names; that the
foregoing Resolutions now stand of record on the books of the Corporation; and
that the Resolutions are in full force and effect and have not been modified or
revoked in any manner whatsoever.

     IN WITNESS WHEREOF, I have hereunto set my hand on October 12, 1998 and
attest that the signatures set opposite the names listed above are their genuine
signatures.


                                       CERTIFIED TO AND ATTESTED BY:


                                        X 

Attachment 1 - Articles of Incorporation
Attachment 2 - ByLaws

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

                                      2