Congratulations to Dr. Darling (junior) and the rest of the Boston Brethren for this promising work. Wound Ischemia Foot Infection divided into none, mild moderate and severe works!
The Society for Vascular Surgery (SVS) WIfI (wound, ischemia, foot infection) classification system was proposed to predict 1-year amputation risk and benefit from revascularization. Our goal was to evaluate the ability of this scale to predict major amputation, mortality, and revascularization, major amputation, or stenosis (RAS) events (>3.5× step-up by duplex) for patients undergoing a first-time lower extremity revascularization for critical limb ischemia (CLI).
From 2005 to 2014, 1177 patients fit our criteria. Patients were stratified into clinical stages 1 to 4 based on the SVS WIfI classification for 1-year amputation risk estimation as well as a novel composite score from 0 to 9 and a novel mean score from 0 to 3. Outcomes included RAS events, major amputation, and mortality. Predictors were identified using Cox regression models.
In 1177 patients (585 endovascular, 592 bypass; 19% rest pain, 81% tissue loss), Cox regression demonstrated that an increase in WIfI clinical stage increased the rate of major amputation (hazard ratio [HR], 2.2; 95% confidence interval [CI], 1.6-3.1). Separate models of the entire cohort, a bypass-only cohort, and an endovascular-only cohort showed that an increase in the mean WIfI score is associated with an increase in RAS events (entire cohort: HR, 1.4 [95% CI, 61.2-1.6]; bypass-only cohort: HR, 1.6 [95% CI, 1.3-2.1]), major amputations (all models: HR, 4.5 [95% CI, 3.1-6.5], 4.1 [95% CI, 2.5-6.6], and 5.8 [95% CI, 3.5-3.6], respectively), and mortality (entire cohort: HR, 1.2 [95% CI, 1.0-1.5]; Table 1). WIfI clinical stage did not predict RAS events or mortality.
This study supports the ability of the SVS WIfI clinical stage to predict major amputation. Furthermore, the mean and composite WIfI scores predict amputation, RAS events, and mortality after open and endovascular procedures.