Exhibit 10.11
ASSUMPTION OF LEASE
     Reference is made to the Lease between Triumph 1450 LLC (the “Lessor”) and
Replidyne, Inc. (“Replidyne”), dated as of October 25, 2005, as amended
August 25, 2006 (the “Lease”). In connection with the business combination
transaction contemplated by that certain Agreement and Plan of Merger and
Reorganization by and among Replidyne, Responder Merger Sub, Inc. and
Cardiovascular Systems, Inc., a Minnesota corporation, dated as of November 3,
2008, and effective as of February 25, 2009, Cardiovascular Systems, Inc., a
Delaware corporation (the “Company”), hereby assumes all of Replidyne’s
obligations under the Lease and agrees to perform all of the covenants and
conditions of the Lease required of Replidyne as set forth therein. This
Assumption of Lease is being provided to Lessor pursuant to the terms of
Section 12.2(a) of the Lease.

            COMPANY:
CARDIOVASCULAR SYSTEMS, INC.
    Dated: 3/19/09  By:   /s/ James E. Flaherty         Name:   James E.
Flaherty        Its: Chief Administrative Officer     

     The undersigned Lessor hereby acknowledges the foregoing Assumption of
Lease.

            LESSOR:
SHMAEL 9450 INVESTORS LLC
    Dated: 3/23/09  By:   /s/ Jay D. Matthes         Name:   Jay D. Matthes     
  Its: Authorized Signatory