Validation of the Wound, Ischemia, foot Infection (WIfI) classification system in nondiabetic patients treated by endovascular means for critical limb ischemia

Abstract

The Society for Vascular Surgery Lower Extremity Guidelines Committee developed the Wound, Ischemia, foot Infection (WIfI) a classification system to predict the amputation risk in patients with critical limb ischemia (CLI). A number of published studies have already evaluated its prognostic value. However, most of the included patients were diabetic, and the validation was done independent of the revascularization procedure. This single-center study evaluated the prognostic value of WIfI stages in nondiabetic patients treated by endovascular means. A retrospective analysis was performed of prospectively collected data of nondiabetic patients treated by endovascular means between January 2013 and September 2014. All patients were classified according to their wound status, ischemia index, and extent of foot infection to four classes: very low risk, low risk, moderate risk, and high risk. Comorbidities and vascular lesions for each group were analyzed. The prognostic value of WIfI was analyzed based on the amputation-free survival, overall survival rate, and freedom from amputation at 12months. Data from 302 CLI patients treated in the study period were reviewed. A total of 219 patients (73%) underwent an endovascular intervention, and among them, 126 nondiabetic patients (58%) were enrolled in this study. Most patients were classified as low risk (33%), and the prevalence of very low-risk, moderate-risk, and very high-risk patients was 23%, 23%, and 21%, respectively. The modified Edifoligide for the Prevention of Infrainguinal Vein Graft Failure (PREVENT III) scorewas statistically significantly higher in the high-risk group (5.2± 2.4) than in the very low-risk, low-risk, and moderate-risk groups (4.3± 2.5, 3.5± 2.3, 4.5± 2.2, respectively; P= .048). One major amputation (1%) was performed during the hospital stay in a high-risk patient. Mean follow-up was 14± 8months. The amputation-free survival at 12months was 87%, 81%, 81%, and 62%, in the very low-risk, low-risk, moderate risk, and very high-risk groups, respectively (P= .106). The difference was statistically significant between the very low-risk and high-risk groups (hazard ratio, 3.4; 95% confidence interval, 1.1-10.3; P= .029). A similar trend was also observed for 1-year survival between the very low-risk and the high-risk groups (87%, 84%, 81%, 65%; P= .166). The amputation rate during the follow-up time was 0%, 2% (n= 6), 3% (n= 5), and 12% (n= 9) for the very low-risk, low-risk, moderate-risk, and very high-risk groups, respectively (P= .033). The WIfI classification system predicted the amputation risk and survival in this highly selected group of nondiabetic CLI patients treated by endovascular means, with a statistically significant difference between very low-risk and high-risk patients already at 1year.