Risk Factors for Major Amputation in Chronic Limb-Threatening Ischemia Patients Classified as Wound, Ischemia, and Foot Infection Stage 4 following Infrainguinal Revascularization.

ABSTRACT

BACKGROUND: To evaluate limb salvage outcomes and risk factors for major amputation in chronic limb-threatening ischemia (CLTI) patients classified as stage 4 per the wound, ischemia, and foot infection (WIfI) classification following infrainguinal revascularization. METHODS: We retrospectively analyzed multicenter data of patients who had undergone infrainguinal revascularization for CLTI between 2015 and 2020. The endpoint was secondary major amputation defined as an above- or below-knee amputation following infrainguinal revascularization. RESULTS: We analyzed 243 patients with CLTI and 267 limbs. Bypass surgery was performed in 14 (25.5%) and 120 (56.6%) limbs from the secondary major amputation and limb salvage groups, respectively (P < 0.01). Endovascular therapy (EVT) was performed in 41 limbs (74.5%) in the secondary major amputation group and 92 limbs (43.4%) in the limb salvage group (P < 0.01). The average serum albumin levels were 3.0 ± 0.6 and 3.4 ± 0.5 g/dL in the secondary major amputation and limb salvage groups, respectively (P < 0.01). The percentage of congestive heart failure (CHF) was 36.4% and 14.2% in secondary major amputation and limb salvage groups, respectively (P < 0.01). The number of limbs with infra-malleolar (IM) P0, P1, and P2 were 4 (7.3%), 37 (67.3%), and 14 (25.5%), respectively, in the secondary major amputation group and 58 (27.4%), 140 (66.0%), and 14 (6.6%), respectively, in the limb salvage group (P < 0.01). Limb salvage rates at 1 year were 91.0% and 68.6% in the bypass and EVT groups, respectively (P < 0.01). Limb salvage rates at 1 year in patients with IM P0, P1, and P2 were 91.8%, 79.9%, and 53.1%, respectively (P < 0.01). Multivariate analysis revealed that serum albumin level [hazard ratio (HR), 0.56; 95% confidence interval (CI), 0.36-0.89; P = 0.01], hypertension (HR, 0.39; 95% CI, 0.21-0.75; P < 0.01), CHF (HR, 2.10; 95% CI, 1.09-4.05; P = 0.03), wound grade (HR, 1.72; 95% CI, 1.03-2.88; P = 0.04), IM P (HR, 2.08; 95% CI, 1.27-3.42; P < 0.01), and EVT (HR, 3.31; 95% CI, 1.77-6.18; P < 0.01) as independent risk factors for secondary major amputation being required. CONCLUSIONS: Among CLTI patients with WIfI stage 4, the limb salvage rate was poor in those with IM P1-2 following infrainguinal EVT. Low serum albumin levels, CHF, high wound grade, IM P1-2, and EVT were independent risk factors for CLTI patients requiring major amputation.