Development and Validation of a New Scoring System to Predict Wound Healing After Endovascular Therapy in Critical Limb Ischemia With Tissue Loss

Abstract

Purpose: To develop a scoring system to predict wound healing in critical limb ischemia (CLI) patients treated with endovascular therapy (EVT). Methods: Between July 2007 and January 2013, 184 patients (118 men; mean age 73.0 years) with CLI (217 limbs) and tissue loss underwent EVT. From this cohort 236 separate wounds were divided into development (n=118) and validation (n=118) groups. Predictors of wound healing were identified using multivariable analysis. Each predictor was assigned a score based on its regression coefficient, and total scores were calculated, ranging from 0 to 1 for low risk up to ≥4 for high risk of a nonhealing wound. The performance of the scoring system in the prediction of wound healing was evaluated by calculating the area under the receiver operating characteristics (ROC) curve. Results: By multivariable analysis, a University of Texas grade ≥2 (HR 0.524, 95% CI 0.288–0.951, p=0.034), an infected wound (HR 0.497, 95% CI 0.276–0.894, p=0.020), dependence on hemodialysis (HR 0.459, 95% CI 0.259–0.814, p=0.008), no visible blood flow to the wound (HR 0.343, 95% CI 0.146–0.802, p=0.014), and major tissue loss (HR 0.322, 95% CI 0.165–0.630, p=0.001) predicted a non-healing wound. The 1-year rates of wound healing in the low-, intermediate-, and high-risk groups were 94.6%, 67.6%, and 9.1%, respectively, in the development group (p<0.001) and 92.3%, 70.5%, and 31.3%, respectively, in the validation sample (p<0.001). The area under the ROC curve was 0.922 in the development group and 0.808 in the validation sample. Conclusion: This scoring system reliably predicts wound healing in CLI patients after endovascular revascularization and is potentially helpful in deciding if additional adjuncts or revascularization should be considered.