X0306 4 2022-08-12 0001180145 Cardiovascular Systems Inc CSII 0001680771 Rosenstein Alexander 1225 OLD HIGHWAY 8 NW ST. PAUL MN 55112 1 General Counsel & Corp. Sec. Common Stock 2022-08-12 4 F 0 2601 16.64 D 155535 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. /s/ Andrew Nick as Attorney-in-Fact for Alexander Rosenstein pursuant to Power of Attorney previously filed. 2022-08-16