Risk Factors for Wound Complications and 30-Day Mortality after Major Lower Limb Amputations in Patients with Peripheral Arterial Disease

Purpose: Risk factors for wound complications or 30-day mortality after major amputation in patients with peripheral arterial disease remain unclear. We investigated the outcomes of major amputation in patients with peripheral arterial disease. Methods: Patients who underwent major amputation from 2008 to 2015 were retrospectively analyzed. The main outcome measures were risk factors for wound complications and 30-day mortality after major lower limb amputations. Major amputation was defined as above-knee amputation or below-knee amputation. Wound complications were defined as surgical site infection or wound dehiscence. Results: In total, 106 consecutive patients underwent major amputation. The average age was 77.3 +/- 11.2 years, 67.9% of patients had diabetes mellitus and 35.8% were undergoing hemodialysis. Patients who underwent primary amputation constituted 61.9% of the cohort, and the proportions of above-knee amputation and below-knee amputation were 66.9% and 33.1%, respectively. The wound complication rate was 13.3% overall, 10.3% in above-knee amputation, and 19.5% in below-knee amputation. Multivariate analysis showed that the risk factors for wound complications were female sex (hazard ratio, 4.66; 95% confidence interval, 1.40-17.3; P = 0.01) and below-knee amputation (hazard ratio, 4.36; 95% confidence interval, 1.20-17.6; P = 0.03). The 30-day mortality rate was 7.6%, pneumonia comprised the most frequent cause of 30-day mortality, followed by sepsis and cardiac death. Multivariate analysis showed that a low serum albumin concentration (hazard ratio, 3.87; 95% confidence interval, 1.12-16.3; P = 0.03) was a risk factor for 30-day mortality. Conclusions: Female sex and below-knee amputation were risk factors for wound complications. A low serum albumin concentration was a risk factor for 30-day mortality after major amputation in Japanese patients with peripheral arterial disease.