The percentage of patients undergoing closed lower extremity major amputation (below, thru or above knee) for ischemic arterial disease who do NOT have unplanned reoperation during the same admission for infection, bleeding or amputation revision. Rationale: Major closed amputations (below and above knee) can be complicated by infection, bleeding or failure to heal, resulting in unplanned reoperation, if the level and conduct of the initial procedure is not appropriate. This outcome measure appropriately identifies proper amputation level selection and proper surgical technique.