Long-Term Mortality After Major Lower Extremity Amputation for Dysvascular or Infected Limbs

OBJECTIVE: Previous studies have reported poor survival rates after major amputation for dysvascular or infected limbs. In this study, we examined contemporary long-term survival rates and causes of death among patients undergoing major lower extremity amputation. METHODS: Institutional medical records were queried for patients undergoing either above-knee (AKA) or below-knee amputation (BKA) for chronic limb-threatening ischemia (CLTI) or severe infection, from 2020-2023. Mortality rates were evaluated using Kaplan-Meier survival curves, and Cox proportional hazards models were constructed to identify risk factors. RESULTS: A total of 747 patients underwent major amputation over the four-year period, with a median follow-up of 1.2 years. Median age was 65 years old and 62.7% were male sex. AKAs (n=371, 49.7%) and BKAs (n=376, 50.3%) were evenly distributed. The overall 30-day, one-year, and three-year survival rates were 91.9% (95% confidence interval [CI], 89.9-93.9%), 72.8% (95% CI, 69.4-76.2%), and 49.0% (44.3-53.7%), respectively. Amputation-related causes of death comprised 15.9% of all patient mortalities, with a median interval of 24 postoperative days (interquartile range, 8-64). Risk factors for overall mortality included patient age (hazard ratio [HR] 1.02 per year, 95% CI 1.01-1.03, p < .001), AKA (vs BKA; HR 1.76, 95% CI 1.39-2.25, p < .001), emergent amputation (versus elective; HR 8.59, 95% CI 3.12-17.84, p < .001), chronic kidney disease (HR 1.37, 95% CI 1.04-1.80, p = .026), end-stage renal disease (HR 1.41, 95% CI 1.00-1.98, p = .048), and coronary artery disease (HR 1.36, 95% CI 1.08-1.71, p = .010). CONCLUSION: Long-term mortality rates remain substantial among patients undergoing major lower extremity amputation. However, only a small fraction of these deaths are attributable to the amputation procedure or postoperative complications. Risk factors for overall mortality include advanced patient age, emergent operation, and the presence of significant medical comorbidities. These findings highlight the importance of comprehensive risk assessment and may aid in prognostication and shared decision-making for patients with CLTI or severe infection considering major amputation.