POWER OF ATTORNEY





 The undersigned hereby constitutes and appoints David L. Martin, James E.

Flaherty, Robert K. Ranum and John R. Remakel, or any one of them acting alone,

the undersigned's true and lawful attorney-in-fact and agent with full power of

substitution and resubstitution, for the undersigned and in the undersigned's

name, place and stead, in any and all capacities, to sign any or all Forms 3, 4

or Form 5 relating to beneficial ownership of securities of Cardiovascular

Systems, Inc. (the "Issuer"), to file the same, with all exhibits thereto and

other documents in connection therewith, with the Securities and Exchange

Commission and to deliver a copy of the same to the Issuer, granting unto said

attorney-in-fact and agent full power and authority to do and perform each and

every act and thing requisite and necessary to be done in and about the

premises, as fully to all intents and purposes as the undersigned might or

could do in person, hereby ratifying and confirming all said attorney-in-fact

and agent, or his substitute or substitutes, may lawfully do or cause to be

done by virtue thereof.  The undersigned acknowledges that the foregoing

attorney-in-fact, in serving in such capacity at the request of the

undersigned, is not assuming any of the undersigned's responsibilities to

comply with Section 16 of the Securities Exchange Act of 1934.



 This Power of Attorney shall remain in effect until such time as the

undersigned is no longer subject to the provisions of Section 16 of the

Securities Exchange Act of 1934 with respect to securities of the Issuer.



 The undersigned hereby indemnifies the attorneys-in-fact for all losses

and costs the attorneys-in-fact may incur in connection with or arising from the attorneys-in-fact's execution of their authorities granted hereunder.



 IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to

be executed as of this 25th day February, 2009.







       /s/ Paul Tyska

       Paul Tyska