Scoring Model to Predict Major Amputation in Patients With Chronic Limb-Threatening Ischemia at Wound, Ischemia, and Foot Infection Clinical Stage 4 After Endovascular Therapy

Purpose: We investigated the predictors of major amputation (MA) at 1 year and prepared a scoring model to stratify the clinical outcomes of chronic limb-threatening ischemia (CLTI) patients at wound, ischemia, and foot infection (WIfI) clinical stage 4 after endovascular therapy (EVT). Materials and Methods: This study was a retrospective, observational study performed at a single center. A total of 353 CLTI patients (390 limbs) were treated with EVT between April 2007 and December 2016. Among these, limbs at WIfI clinical stages 1, 2, and 3 were excluded, and 194 limbs at WIfI clinical stage 4 (49.7%) were enrolled. The primary endpoint was major amputation (MA) free rate at 1 year. Predictors of MA at 1 year was evaluated by Cox proportional hazard analysis. Results: At 1 year, the incidence of MA was 18.0% (35 limbs). Cox proportional hazard analysis revealed that hemodialysis (hazard ratio [HR] 2.63; 95% confidence interval [CI], 1.24-5.58; p=0.012), fI3 (HR 2.54; 95% CI, 1.28-5.06; p=0.008), toe wounds (HR 0.29; 95% CI, 0.094-0.88; p=0.029), and visible blood flow to the wound (HR 0.43; 95% CI, 0.21-0.89; p=0.023) were associated with MA. We assigned 1 point for positive predictors of MA, hemodialysis, and fI3; 1 point was deducted for negative predictors of MA, toe wounds, and visible blood flow to the wound. A score of -2 or -1, was defined as the low-risk group, 0 was defined as the intermediate-risk group, and +1 or +2 were defined as the high-risk group. At 1 year, MA free rate, wound healing rate, and amputation-free survival rate were stratified according to a scoring model. MA free rate was 96.6% in low-risk, 72.4% in intermediate-risk, and 67.3% in high-risk (p<0.001); wound healing rate was 67.8% in low-risk, 27.6% in intermediate-risk, and 4.1% in high-risk (p<0.001); amputation-free survival rate was 65.3% in low-risk, 44.8% in intermediate-risk, and 18.4% in high-risk (p<0.001). Conclusions: The scoring model based on the predictors of MA stratified clinical outcomes in CLTI patients at WIfI clinical stage 4.