SLR - June 2021 - Michael V. Florie

Evaluation of Revascularization Benefit Quartiles using the WIfI Classification System for Diabetic Patients with Chronic Limb-Threatening Ischemia

Reference: Hicks CW, Canner JK, Sherman RL, Black JH 3rd, Lum YW, Abularrage CJ. Evaluation of Revascularization Benefit Quartiles using the WIfI Classification System for Diabetic Patients with Chronic Limb-Threatening Ischemia. J Vasc Surg. 2021 Apr 1:S0741-5214(21)00472-9. 

Level of Evidence: Level III

Scientific Literature Review

Reviewed By: Michael V. Florie, DPM
Residency Program: Southern Arizona Veterans Affairs Health Care System – Tucson, AZ

Podiatric Relevance: Diabetic foot ulcers are one of the most common conditions Podiatrists deal with on a day to day basis. Treating a diabetic foot ulcer is multifactorial and our understanding of diabetes as it pertains to wounds and limb salvage continues to improve. The WiFi classification system was created to help stratify risk of one-year amputation for diabetic foot ulcers and has proven to be a useful tool. One of the driving factors to diabetic foot wounds is the vascular component, specifically lack of adequate vascular supply. Revascularization is a common procedure done by vascular surgeons in effort to help improve blood flow and is critical in patients with chronic limb ischemia. This study evaluates the benefit quartiles of revascularization in people with diabetes, 136 individuals, with chronic limb ischemia. 

Methods: A group of 136 people with diabetes and 187 limbs underwent revascularization via endovascular approach in 66.8 percent of cases and open approach in 33.2 percent of cases. Affected limbs were graded according to the WiFi classification system and assigned to benefit from revascularization quartiles. The one-year amputation rate, complete wound healing, secondary patency, and amputation free survival were calculated between quartiles using Kaplan Meier curve analyses and Cox proportional hazard models. 

Results: Of all limbs 27.3 percent had a high benefit of revascularization (Q1), 36.6 percent had a moderate benefit (Q2), 20.3 percent had a low benefit (Q3) and 20.9 percent had a questionable benefit of revascularization (Q4). The estimated one-year amputation rates for Q1 were 7.2 percent, 3.8 percent for Q2, 7.0 percent for Q3 and 25.7 percent for Q4. The overall secondary patency and amputation-free survival did not have significant difference between groups. Based on the Cox Proportional Hazard Model the Q4 group had a significantly higher risk of amputation compared to Q1. Nine of the fourteen limbs that resulted in major amputation had patent revascularizations. 

Conclusions: The study found that the questionable estimated revascularization benefit quartile (Q4) is significantly associated with greater risk of major amputation within one year in patients with diabetes presenting with chronic limb ischemia. These limbs frequently require major amputation even with patent revascularizations. This suggests that wound size and infection burden are driving factors behind greater risk for major amputation in this group. These findings support previously described use of the WIfI classification system to predict the benefit from revascularization among patients with diabetes with chronic limb-threatening ischemia. 

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