SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
X	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* MAVERICK CAPITAL LTD (Last) (First) (Middle) 300 CRESCENT COURT, 18TH FLOOR (Street) DALLAS, TX 75201 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol Cardiovascular Systems Inc [ CSII ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 11/30/2010
	4. If Amendment, Date of Original Filed (Month/Day/Year) 12/02/2010	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

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

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 Securities Underlying Derivative Security (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: 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
Warrants	$9.28	11/30/2010		S			134,790	(2)	09/12/2013	Common Stock	134,790(1)(3)	$3.353	0	I	See Footnotes(1)(3)
Warrants	$8.83	11/30/2010		S			519,798	(2)	02/24/2014	Common Stock	519,798(1)(4)	$3.604	0	I	See Footnotes(1)(4)

1. Name and Address of Reporting Person* MAVERICK CAPITAL LTD (Last) (First) (Middle) 300 CRESCENT COURT, 18TH FLOOR (Street) DALLAS, TX 75201 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* MAVERICK CAPITAL MANAGEMENT LLC (Last) (First) (Middle) 300 CRESCENT COURT, 18TH FLOOR (Street) DALLAS, TX 75201 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* AINSLIE LEE S III (Last) (First) (Middle) 767 FIFTH AVENUE, 11TH FLOOR (Street) NEW YORK, NY 10153 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. Maverick Capital, Ltd. ("Maverick Capital") is a registered investment adviser under the Investment Advisers Act of 1940, as amended and acts as the investment manager for each of the portfolio funds that directly hold the reported securities. Maverick Capital Management, LLC ("Maverick") is the general partner of Maverick Capital. Lee S. Ainslie III is the manager of Maverick who is granted sole investment decision pursuant to Maverick's limited liability company regulations. Each reporting owner disclaims beneficial ownership of the reported securities except to the extent of pecuniary interest therein.

2. The Warrants are exercisable at anytime at the holder's election.

3. Prior to the transactions reported on this Form 4, Warrants to acquire 59,280 shares of Common Stock were held by Maverick Fund L.D.C.; Warrants to acquire 23,932 shares of Common Stock were held by Maverick Fund USA, Ltd.; and Warrants to acquire 51,578 shares of Common Stock were held by Maverick Fund II, Ltd.

4. Prior to the transactions reported on this Form 4, Warrants to acquire 228,603 shares of Common Stock were held by Maverick Fund L.D.C.; Warrants to acquire 92,291 shares of Common Stock were held by Maverick Fund USA, Ltd.; and Warrants to acquire 198,904 shares of Common Stock were held by Maverick Fund II, Ltd.

	/s/ John T. McCafferty, Attorney-in-Fact	12/02/2010
	/s/ John T. McCafferty, Attorney-in-Fact	12/02/2010
	/s/ John T. McCafferty, Attorney-in-Fact	12/02/2010
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* 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).
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