Predictors of Major Adverse Limb Events after Open Forefoot Amputation in Patients with Chronic Limb-Threatening Ischemia

Background: Management of patients with chronic limb-threatening ischemia (CLTI) and extensive foot necrosis presents a challenge for limb salvage. Our study evaluates preoperative risk factors that contributed to durability and efficacy of limb salvage after open transmetatarsal amputation (TMA) in patients with critical limb-threatening ischemia. Methods: We abstracted data from patients who underwent open TMA at Los Angeles County-University of Southern California Medical Center and Keck Hospital of University of Southern California from 2009 to 2018. Multivariable logistic regression analysis, adjusting for preoperative risk factors, was used to examine predictors of major adverse limb events (MALE). The aim was to evaluate outcomes following open TMA with MALE as the primary outcome. Our hypotheses were that outcomes would be worse for patients with foot infections and renal failure. Results: Forty-three open TMAs were done in 39 patients during the study period. The cohort had a mean age of 63 ± 11.6 years, 89% had a history of diabetes, 95% hypertension (HTN), 54% had end-stage renal disease (ESRD), and 26% were current smokers. MALE occurred in 39% of the cohort. Sex, race, indication, HTN, smoking status, and history of prior ipsilateral revascularization or minor amputations were not associated with MALE (P > 0.05). Multivariate logistic regression found ESRD to be an independent predictor of MALE (odds ratio 7.43, 95% confidence interval 1.12–49.17, P = 0.038) after adjusting for clinically significant covariates. Conclusions: Open TMA provides acceptable rates of limb salvage for complex patients with CLTI. ESRD is an independent risk factor for MALE following open TMA in these patients. Vigilant follow-up is essential for this morbid patient population given poorer outcomes after forefoot amputation.