Sec Form 4 Filing - NELSON GLEN D @ Cardiovascular Systems Inc - 2014-08-11

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 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

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1. Name and Address of Reporting Person NELSON GLEN D 2. Issuer Name and Ticker or Trading Symbol Cardiovascular Systems Inc [ CSII] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 651 CAMPUS DRIVE 3. Date of Earliest Transaction (MM/DD/YY) 08/11/2014 (Street) ST. PAUL, MN55112 4. If Amendment, Date Original Filed (MM/DD/YY) 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 (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 431,588 D Common Stock 28,500 I By Family Trust ( 1 ) Common Stock 939,257 I Held by LLC ( 2 )

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 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 Stock Option (right to buy) $ 12.37 ( 3 ) 11/30/2015 Common Stock 9,705 9,705 D Stock Option (right to buy) $ 9.28 ( 3 ) 11/30/2014 Common Stock 6,470 6,470 D Stock Option (right to buy) $ 8.83 ( 3 ) 12/18/2016 Common Stock 12,940 12,940 D Stock Option (right to buy) $ 7.9 ( 3 ) 10/08/2017 Common Stock 4,322 4,322 D Stock Option (right to buy) $ 11.38 ( 3 ) 11/12/2017 Common Stock 15,087 15,087 D Restricted Stock Units ( 4 ) ( 4 ) ( 4 ) Common Stock 5,714 5,714 D Restricted Stock Units ( 4 ) ( 4 ) ( 4 ) Common Stock 11,628 11,628 D Restricted Stock Units ( 4 ) ( 4 ) ( 4 ) Common Stock 21,739 21,739 D Restricted Stock Units ( 4 ) ( 4 ) ( 4 ) Common Stock 7,192 7,192 D Restricted Stock Units ( 4 ) ( 4 ) ( 4 ) Common Stock 10,917 10,917 D Restricted Stock Units ( 5 ) 08/13/2015 08/13/2015 Common Stock 4,581 4,581 D Restricted Stock Units ( 4 ) ( 4 ) ( 4 ) Common Stock 4,580 4,580 D Restricted Stock Units ( 5 ) 08/11/2014 A 3,749 ( 6 ) 08/16/2016 08/16/2016 Common Stock 3,749 $ 0 3,749 D Restricted Stock Units ( 7 ) 08/11/2014 A 4,260 ( 7 ) ( 7 ) Common Stock 4,260 $ 0 4,260 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other NELSON GLEN D 651 CAMPUS DRIVE ST. PAUL, MN55112 X Signatures /s/ Amanda Schmall as Attorney-in-Fact for Glen D. Nelson pursuant to Power of Attorney previously filed. 08/13/2014 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Shares are held by the Glen D. Nelson 2012 Family Trust for the benefit of Dr. Nelson's wife and descendants. ( 2 )Shares are held by GDN Holdings, LLC, of which Dr. Nelson is the sole owner. ( 3 )Fully exercisable. ( 4 )Each restricted stock unit represents the right to receive a payment from CSI equal in value to the market price per share of CSI common stock on the date of payment, and will be payable in cash or shares of the Company's Common Stock beginning six months following the termination of the reporting person's board membership. ( 5 )Each restricted stock unit represents the right to receive a payment from CSI equal in value to the market price per share of CSI common stock on the date of payment, and will be payable in cash or shares of the Company's Common Stock on the payment date. ( 6 )Represents restricted stock units received at the election of the reporting person, in lieu of cash payment, as a retainer for service as a director of the Company during fiscal year 2015. ( 7 )Each restricted stock unit represents the right to receive a payment from CSI equal in value to the market price per share of CSI common stock on the date of payment, and shall be payable in cash or shares of Company common stock beginning six months following the termination of each director's board membership; provided, however, that the restricted stock units vest in quarterly amounts of 1,065 on each of September 30, 2014, December 31, 2014, March 31, 2015 and June 30, 2015.

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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