FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL OMB Number: 3235-0287 Expires: January 31, 2005 Estimated average burden hours per response... 0.5

(Print or Type Responses)

1. Name and Address of Reporting Person * Cohen Lawrence   2. Issuer Name and Ticker or Trading Symbol THORATEC CORP [THOR] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Division President (Last) (First) (Middle) 6035 STONERIDGE DRIVE 3. Date of Earliest Transaction (Month/Day/Year) 03/03/2010 (Street) PLEASANTON, CA 94588 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock (2) 03/03/2010   A   4,643 A $ 0 (1) 32,329 D   Common Stock 03/04/2010(4)   M   20,000 A $ 12.45 52,329 D   Common Stock 03/04/2010(4)   S   20,000 D $ 30.5 32,329 D

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
	Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.		SEC 1474 (9-02)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Non-Qualified Stock Option (right to buy)

$ 29.81

03/03/2010

A

13,929

03/03/2011(3)

03/03/2020

Common Stock

13,929

$ 0 (1)

13,929

D

Non-Qualified Stock Option (right to buy)

$ 12.45

03/04/2010(4)

M

20,000

10/14/2004(5)

04/14/2014

Common Stock

20,000

$ 0 (1)

47,387

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Cohen Lawrence 6035 STONERIDGE DRIVE PLEASANTON, CA 94588			Division President

Signatures

/s/David A. Lehman, Attorney-In-Fact		03/05/2010
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Options and restricted stock units were granted pursuant to the Company's equity incentive plan with no payments received for either.
(2)	Represents restricted stock units. Each restricted stock unit represents a right to receive one share of Thoratec Corporation common stock upon vesting. The restricted stock units vest in four equal annual installments commencing one year after the grant date.
(3)	Options vest in four equal annual installments commencing one year after the grant date.
(4)	Options exercised and shares of Common Stock sold pursuant to a Sales Plan established by the Reporting Person on August 10, 2009, which Sales Plan is intended to comply with the requirements of Rule 10b5-1(c)(1) under the Securities Exchange Act of 1934, as amended.
(5)	Options vest in six equal installments commencing 6 months after the grant date.

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.