X0306 4 2023-02-12 0001180145 Cardiovascular Systems Inc CSII 0001818614 Rempe Stephen J. 1225 OLD HIGHWAY 8 NW ST. PAUL MN 55112 0 1 0 0 Chief Human Resources Officer Common Stock 2023-02-12 4 F 0 984 19.70 D 78417 D Common Stock 2023-02-13 4 A 0 5077 0 A 84220 D The reporting person has elected to satisfy his tax withholding obligation in connection with the vesting of prior restricted stock grants by directing the Company to withhold shares otherwise issuable upon vesting of the previously reported grants. Restrictions lapse as to 2,539 shares on 2/14/24 and as to 2,538 shares on 2/14/25. Includes 726 shares acquired on 12/31/22 pursuant to the Company's Employee Stock Purchase Plan. /s/ Andrew Nick as Attorney-in-Fact for Stephen J. Rempe pursuant to Power of Attorney previously filed. 2023-02-14