X0306 4 2012-08-24 0001180145 Cardiovascular Systems Inc CSII 0001243511 BETTERLEY LAURENCE L 651 CAMPUS DRIVE ST. PAUL MN 55112 0 1 0 0 Chief Financial Officer Common Stock 2012-08-24 4 S 0 416 9.03 D 199909 D Stock Option (right to buy) 8.75 2019-03-01 Common Stock 14234 14234 D In connection with the vesting and delivery of restricted stock, and pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on November 30, 2011, on each date shares were sold and the net proceeds were used to pay required withholding taxes. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $8.98 to $9.20 inclusive. The reporting person undertakes to provide Cardiovascular Systems, Inc., any security holder of Cardiovascular Systems, Inc. or the staff of the Securities and Exchange Commission upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. Fully exerciable. /s/ Scott J. Dorfman as Attorney-in-Fact for Laurence L. Betterley pursuant to Power of Attorney previously filed. 2012-08-28