Abstract
BACKGROUND: Life expectancy is short for patients with critical limb ischemia (CLI), many of whom may fear amputation more than death. In light of the reduced life expectancy of these patients, the traditional 5-year freedom from amputation (FFA) statistic may not accurately address their concern. We developed a more relevant patient-centered calculation of major amputation risk during a patient's remaining lifetime to better answer the question, Will I ever lose my leg? METHODS: We identified all limbs undergoing first-time intervention for CLI in a large institutional database from 2005 to 2013. We calculated the traditional metrics of amputation-free survival (AFS, for which failure is death or amputation) and FFA (for which failure is amputation but deaths are censored and removed from further analysis). In addition, we propose a new term, lifelong limb preservation (LLP). LLP defines amputation as failure, but deaths are not censored and therefore reflect that LLP has been achieved. All deaths before 30 days were considered a failure in all three metrics, reflecting the risk of surgery. RESULTS: There were 1006 limbs identified as having first-time intervention for CLI (22% rest pain, 45% ulcer, 27% gangrene; 46% treated by angioplasty with or without stenting, 54% bypass). Using life-table analysis, 7-year AFS was 14% (561 events), FFA was 78% (123 events), and LLP was 86% (123 events). LLP was similar between patients undergoing angioplasty with or without stenting and bypass (7-year rates, 86% and 85%, respectively). For patients undergoing intervention for rest pain, 7-year rates were 14% for AFS, 84% for FFA, and 92% for LLP. For those undergoing treatment for ulcer, 7-year rates were 14% for AFS, 77% for FFA, and 86% for LLP. Finally, in those with gangrene, rates were 10% for AFS, 67% for FFA, and 79% for LLP. Using LLP, patients presenting with an ulcer can be told that although we cannot guarantee how long they will live, with revascularization there is approximately an 86% chance they will not lose the leg. CONCLUSIONS: These results show that the durability of our limb preservation efforts often exceeds the life expectancy of our patients. Using LLP as an outcomes assessment provides a more accurate and patient-centered answer to the question, If I have this procedure, will I ever lose my leg?