WARRANT TO PURCHASE [NUMBER OF SHARES] SHARES OF COMMON STOCK OF CARDIOVASCULAR SYSTEMS, INC

Exhibit 4.2

THE SECURITIES EVIDENCED HEREBY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR APPLICABLE STATE SECURITIES LAWS. THESE SECURITIES AND THE SECURITIES ISSUABLE UPON EXERCISE HEREOF HAVE BEEN ACQUIRED FOR INVESTMENT AND MAY NOT BE OFFERED FOR SALE, SOLD, ASSIGNED, TRANSFERRED, PLEDGED, OR OTHERWISE DISPOSED OF, AND NO TRANSFER OF THE SECURITIES WILL BE MADE BY THE COMPANY OR ITS TRANSFER AGENT, IN THE ABSENCE OF SUCH REGISTRATION OR AN OPINION OF COUNSEL ACCEPTABLE TO THE COMPANY THAT SUCH REGISTRATION IS NOT REQUIRED.

WARRANT
TO PURCHASE [NUMBER OF SHARES] SHARES OF COMMON STOCK OF
CARDIOVASCULAR SYSTEMS, INC.

      FOR VALUE RECEIVED , [NAME] or registered assigns (the “Holder” ), is entitled to purchase from Cardiovascular Systems, Inc., a Minnesota corporation (the “Company” ), [NUMBER OF SHARES] ( [NUMBER OF SHARES]) fully paid and nonassessable shares of the Company’s Common Stock (such shares of Common Stock as may be acquired upon exercise hereof being hereinafter referred to as the “Warrant Shares” ), at an exercise price of $5.71 per share (the “Warrant Exercise Price” ), which Warrant is immediately exercisable. This Warrant shall expire on February 24, 2014.

     This Warrant is subject to the following provisions, terms, and conditions:

     1. The rights represented by this Warrant may be exercised by the Holder, in whole or in part (but not as to a fractional share of Common Stock), by written notice of exercise substantially in the form attached hereto, which notice shall be delivered to the Company accompanied by the surrender of this Warrant (properly endorsed if required) at the principal office of the Company and upon payment to the Company, by cash, certified check or bank draft, of the Warrant Exercise Price for each such Warrant Share subject to the exercise. The Company agrees that the Warrant Shares so purchased shall be and are deemed to be issued as of the close of business on the date on which this Warrant shall have been surrendered and payment made for such Warrant Shares as aforesaid. Certificates for the Warrant Shares so purchased shall be delivered to the Holder within thirty (30) days after the rights represented by this Warrant shall have been so exercised, and, unless this Warrant has expired, a new Warrant representing the number of Warrant Shares, if any, with respect to which this Warrant has not been exercised shall also be delivered to the Holder within such time. Notwithstanding the foregoing, however, the Company shall not be required to deliver any certificates for Warrant Shares, except in accordance with the provisions and subject to the limitations of Section 4 below.

     2. The Company covenants and agrees that all Warrant Shares that may be issued upon the exercise of this Warrant will, upon issuance, be duly authorized and issued, fully paid and nonassessable and free from all taxes, liens, and charges with respect to the issuance thereof. The Company further covenants and agrees that until expiration of this Warrant, the Company will at all times have authorized, and reserved for the purpose of issuance upon exercise of this Warrant, a sufficient number of shares of Common Stock to provide for the exercise of this Warrant.

     3. This Warrant shall not entitle the Holder to any voting rights or other rights as a shareholder of the Company.

     4. The Holder, by acceptance hereof, represents and warrants that (a) it is acquiring this Warrant for its own account for investment purposes only and not with a view to its resale or distribution and (b) it has no present intention to resell or otherwise dispose of all or any part of this Warrant. Other than pursuant to registration under federal and applicable state securities laws or an exemption from such registration, the availability of which the Company shall determine in its reasonable discretion, neither this Warrant nor any Warrant Shares may be sold, pledged, assigned, or otherwise disposed of (whether voluntarily or involuntarily). The Company may condition such sale, pledge, assignment, or other disposition on the receipt from the party to whom this Warrant is to be so transferred or to whom Warrant Shares are to be issued or so transferred of any representations and agreements requested by the Company in order to permit such issuance or transfer to be made pursuant to exemptions from registration under federal and applicable state securities laws. Each certificate representing the Warrant (or any part thereof) and any Warrant Shares shall bear appropriate legends setting forth these restrictions on transferability. The Holder, by acceptance hereof, agrees to give written notice to the Company before transferring this Warrant or any Warrant Shares of the Holder’s intention to do so, describing briefly the manner of any proposed transfer. Within a reasonable period after receiving such written notice, the Company shall notify the Holder as to whether such transfer may be effected and of the conditions to any such transfer.

     5. This Warrant shall be transferable only on the books of the Company by the Holder in person, or by duly authorized attorney, on surrender of the Warrant, properly assigned. Notwithstanding the foregoing, this Warrant shall also be assigned in accordance with Section 8 hereof.

     6. Neither this Warrant nor any terms hereof may be changed, waived, discharged, or terminated orally but only by an instrument in writing signed by the party against which enforcement of the change, waiver, discharge, or termination is sought.

     7.  Net Exercise Rights .

     (a) In addition to and without limiting the rights of the Holder of this Warrant with respect to other terms of this Warrant, the Holder of this Warrant shall have the right (the “Conversion Right”) to convert this Warrant or any portion thereof into Warrant Shares as provided in this Section 7 at any time or from time to time prior to its expiration, subject to the restrictions set forth in paragraph (c) below. Upon exercise of the Conversion Right with respect to a particular number of shares subject to this Warrant (the