POWER OF ATTORNEY



 The undersigned hereby constitutes and appoints Alexander

Rosenstein, Jeffrey Points, Anne Meyer, Amanda Lorentz and Ashley

Brosius, 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 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 20th day of February, 2017.



     /s/ Laurence L. Betterley