The Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system predicts wound healing better than direct angiosome perfusion in diabetic foot wounds

Objective: Previous studies show conflicting results in wound healing outcomes based on angiosome direct perfusion (DP), but few have adjusted for wound characteristics in their analyses. We have previously shown that the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification correlates with wound healing in diabetic foot ulcers (DFUs) treated by a multidisciplinary team. The aim of this study was to compare WIfI classification vs DP and pedal arch patency as predictors of wound healing in patients presenting with DFU and peripheral arterial disease. Methods: We performed a retrospective review of a prospectively maintained database of all patients with peripheral arterial disease presenting to our multidisciplinary DFU clinic who underwent angiography. An angiosome was considered directly perfused if the artery feeding the angiosome was revascularized or was completely patent. Wound healing time at 1 year was compared on the basis of DP vs indirect perfusion, Rutherford pedal arch grade, and WIfI classification using univariable statistics and Cox proportional hazards models. Results: Angiography was performed on 225 wounds in 99 patients (mean age, 63.3 ± 1.2 years; 62.6% male; 53.5% black) during the entire study period. There were 33 WIfI stage 1, 33 stage 2, 51 stage 3, and 108 stage 4 wounds. DP was achieved in 154 wounds (68.4%) and indirect perfusion in 71 wounds (31.6%). On univariable analysis, WIfI classification was significantly associated with improved wound healing (57.2% for WIfI 3/4 vs 77.3% for WIfI 1/2; P =.02), whereas DP and pedal arch patency were not (both, P ≥.08). After adjusting for baseline patient and wound characteristics, WIfI stage remained independently predictive of wound healing (WIfI 3/4: hazard ratio [HR], 0.77; 95% confidence interval [CI], 0.67-0.88), whereas DP (HR, 0.82; 95% CI, 0.55-1.21) and pedal arch grade (HR, 0.85; 95% CI, 0.70-1.03) were not. Conclusions: In our population of patients treated by a multidisciplinary diabetic foot service, the Society for Vascular Surgery WIfI classification system was a stronger predictor of diabetic foot wound healing than DP or pedal arch patency. Our results suggest that a measure of wound severity should be included in all future studies assessing wound healing as an outcome, as differences in patients' wound characteristics may be a strong contributor to the variation of angiosome-directed perfusion results previously observed.