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                            FOURTH AMENDMENT TO LEASE

    THIS FOURTH AMENDMENT TO LEASE is made this 15th day of May, 1998, between 
DAVID D. BOHANNON ORGANIZATION, a California corporation, herein referred to 
as "Landlord", and PERCLOSE, INC., a Delaware corporation, herein referred to 
as "Tenant".

                                   RECITALS

    A.   Landlord and Tenant's predecessor in interest have previously 
entered into a Lease entitled "Business Park Lease" dated July 6, 1993 for 
demised premises located at 195-199 Jefferson Drive, Menlo Park, California, 
as more particularly described in said Lease.

    B.   Landlord and Tenant's predecessor in interest have previously 
entered into a First Amendment to Lease dated January 31, 1995, which First 
Amendment to Lease demised to Tenant certain additional space located at 191 
and 193 Jefferson Drive as more fully set out therein.

    C.   Tenant acquired its interest in the Lease as a result of the 
reincorporation of Perclose, Inc., a California corporation, to Perclose, 
Inc., a Delaware corporation, on or about September 1, 1995.

    D.   Landlord and Tenant have previously entered into a Second Amendment 
to Lease dated September 10, 1996, which Second Amendment to Lease demised to 
Tenant certain additional space located at 177 Jefferson Drive, Menlo Park, 
California, as more fully set out therein.

    E.   Landlord and Tenant have previously entered into a Third Amendment 
to Lease dated March 21, 1998, which Third Amendment to Lease demised to 
Tenant certain additional space located at 171 Jefferson Drive and 175 
Jefferson Drive, Menlo Park, California, as more fully set out therein.  The 
Lease, as previously amended, is herein referred to as the "Lease".

    F.   Landlord and Tenant now wish to extend the demised term of the 
Lease, and otherwise modify the Lease, all as more particularly set forth 
hereinbelow.

    NOW, THEREFORE, in consideration of the covenants and conditions 
contained herein, Landlord and Tenant agree to amend the Lease as follows:

    1.   Effective upon the date first hereinabove written, the demised term 
of the Lease shall, subject to the provisions of paragraph 4 hereinbelow, be 
extended as follows: (i) for the demised premises located at 195-199 
Jefferson Drive, 191 and 193 Jefferson Drive, and 177 Jefferson Drive, from 
October 1, 1998, to and including September 30, 1999; (ii) for the demised 
premises located at 171 Jefferson Drive, from March 1, 1999, to and including 
September 30, 1999; and (iii) for the demised premises located at 175 
Jefferson Drive, from July 1, 1999, to and including September 30, 1999.

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    2.   Base rent payable pursuant to SECTION 2.1. of the Lease, as 
subsequently amended, shall, effective October 1, 1998, be amended as 
follows: for the period from October 1, 1998, to and including September 30, 
1999 (subject to the provisions of paragraph 4 hereinbelow), base rent shall 
be Five Hundred Ninety Five Thousand Four Hundred Fifty Two Dollars 
($595,452.00) per annum, payable in twelve (12) equal monthly installments of 
Forty Nine Thousand Six Hundred Twenty One Dollars ($49,621.00).

    3.   Effective upon the date first hereinabove written, the option to 
extend the demised term of the Lease contained in SECTION 1.3. of the Lease, 
as amended in paragraph 5 of the Third Amendment to Lease, and SECTION 2.3. 
and SECTION 19.20 of the Lease describing base rent during any said renewal 
term, are hereby deemed null and void and of no force or effect, as Landlord 
and Tenant have agreed on an extension of the demised term pursuant to the 
provisions hereof.

    4.   Early Termination.

    A.   Landlord and Tenant agree that, commencing January 1, 1999, Landlord 
may (but without any obligation to do so) market the entire demised premises 
or portions thereof, in allotments described herein, for lease to third 
parties.  Landlord and Tenant agree that Landlord's marketing efforts may be 
apportioned as follows: (i) the entire premises located at 171 Jefferson 
Drive consisting of 3,214 square feet; (ii) the entire premises located at 
175 Jefferson Drive containing 4,000 square feet and/or the entire premises 
located at 177 Jefferson Drive containing 4,000 square feet (i.e., in 
increments of 4,000 square feet or 8,000 square feet); (iii) any one, any 
two, any three or all of the premises located at 191 Jefferson Drive, 193 
Jefferson Drive, 195 Jefferson Drive, 197 Jefferson Drive, and 199 Jefferson 
Drive, each consisting of 4,000 square feet (i.e., in increments of 4,000 
square feet, 8,000 square feet, 12,000 square feet or 20,000 square feet); 
and/or (iv) any combination of the foregoing.  Landlord's marketing efforts, 
with respect to any portion of the demised premises not previously terminated 
as provided herein, may continue until the termination of the Lease for the 
entire demised premises on September 30, 1999.

    B.   Tenant agrees that Tenant shall, within sixty (60) days after the 
date of Landlord's written notice(s), vacate the applicable portion of the 
demised premises (collectively and individually, the "terminated premises")
described in said notice(s) to vacate, and the Lease for such terminated 
premises shall terminate pursuant to the provisions hereof.  Such written 
notice(s) from Landlord to Tenant may be given at any time on or after 
February 1, 1999.  Landlord may give one or more notices for different 
portions of the premises.

    C.   The effective date of termination shall be sixty (60) days after 
the date of Landlord's notice.  Tenant agrees to leave the terminated 
premises in the condition called for under the Lease, including without 
limitation complying with the provisions of the last paragraph of SECTION 
7.4. thereof.  In addition, Tenant shall continue to pay all base rent and 
additional rent applicable to the terminated premises up to and including the 
effective date of termination, or such later date as agreed by Tenant and 
Landlord.

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    D.   The monthly base rent payable pursuant to SECTION 2.1. of the Lease, 
as amended hereinabove, shall be reduced on the effective date of termination 
of the terminated premises as follows: (i) for any portion of the demised 
premises located at 171 Jefferson Drive, 175 Jefferson Drive, and 177 
Jefferson Drive, said monthly base rent shall be reduced by an amount equal 
to the total square feet of the terminated premises multiplied by One and 
50/100 Dollars ($1.50); and (ii) for any portion of the demised premises 
located at 191 Jefferson Drive, 193 Jefferson Drive, 195 Jefferson Drive, 197 
Jefferson Drive, and 199 Jefferson Drive, said monthly base rent shall be 
reduced by an amount equal to the total square feet of the terminated 
premises multiplied by One and 64/100 Dollars ($1.64). For example, if the 
premises located at 177 Jefferson Drive and the premises located at 199 
Jefferson Drive were terminated on the same date pursuant to the provisions 
hereof, then the monthly base rent of $49,621.00 would be reduced by 
$12,560.00 (i.e., $6,000.00 [4,000 square feet x $1.50] plus $6,560.00 
[4,000 square feet x $1.64]) for a new monthly base rent of $37,061.00.

    E.   Tenant's prorata share of the additional rent items which are 
calculated on the basis of the square footage of the demised premises would 
likewise be proportionately reduced on the effective date of termination of 
the terminated premises.

    F.   On or before the effective date of termination as provided 
hereinabove, Landlord and Tenant shall enter into a letter agreement to 
memorialize the termination of the Lease as to the terminated premises 
pursuant to the provisions hereof.

    5.   Except as herein modified, the terms of the Lease are and shall 
remain the same.

    IN WITNESS WHEREOF, the parties have executed this Fourth Amendment to 
Lease as of the date first hereinabove written.

TENANT:                                LANDLORD:

PERCLOSE, INC.,                        DAVID D. BOHANNON ORGANIZATION,
a Delaware corporation                 a California corporation


By: /s/ [Illegible]                    By: /s/ [Illegible]
   -------------------------------        -------------------------------
         Vice President                         Vice President

By: /s/ [Illegible]                    By: /s/ [Illegible]
   -------------------------------        -------------------------------
        Ass't. Secretary                          Secretary


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