Study Supports Use of WIfI Classification System to Predict Revascularization Benefit for Patients With Diabetes and CLTI

October 21, 2021—The Society for Vascular Surgery (SVS) announced the publication of a retrospective study that supports the use of the Wound, Ischemia, and foot Infection (WIfI) classification system to predict the revascularization benefit for diabetic patients with chronic limb-threatening ischemia (CLTI).

Caitlin W. Hicks, MD, et al published the study in Journal of Vascular Surgery (2021;74:1232-1239). The investigators are from the Diabetic Foot and Wound Service at Johns Hopkins University in Baltimore, Maryland.

SVS noted that the WIfI classification system was developed to stratify the risk of major amputation at 1 year for patients presenting with CLTI. The WIfI system had been used to identify patients most likely to benefit from revascularization. WIfI scores were used to define the estimated revascularization benefit quartiles ranging from high benefit (Q1) to questionable benefit (Q4).

“The aim of our study was to evaluate the revascularization benefit quartiles in a cohort of diabetic patients who had presented with critical limb ischemia,” commented Dr. Hicks in the SVS press release.

As summarized by SVS, the investigators evaluated 136 patients with diabetes (187 limbs) who underwent lower extremity revascularization between 2012 and 2020 at their institution. The primary outcome was 1-year major amputation. Demographic characteristics of these diabetic patients included: age 65 ± 11 years; 63% men; presentation with ulcer (51%), gangrene (43%), or rest pain (6%). Revascularization procedures were either endovascular (67%) or open (33%).

The investigators reported that the estimated 1-year amputation rates for each benefit quartile were: Q1, 7 ± 4%; Q2, 4 ± 3%; Q3, 7 ± 5%; Q4, 26 ± 8%. Analysis revealed the Q4 group had a significantly greater risk of amputation compared with the Q1 group (hazard ratio, 4.3). Additionally, of the 137 limbs with > 1-year follow-up after revascularization, 16 (12%) required amputation. Nine of these were in the Q4 group.

“Overall, our data support the use of the WIfI benefit of revascularization quartiles for estimating the 1-year major amputation risk for diabetic patients presenting with critical limb ischemia,” stated Dr. Hicks in the SVS announcement. “We did, however, observe our actual amputation rate in the Q4 group was one-half of what was expected. This may be explained by the fact that all of our diabetic patients are treated by our multidisciplinary team, which has been previously shown to have robust limb salvage outcomes.”

Dr. Hicks added, “Up to one-half of the Q4 patients who underwent amputation did so despite patency of their revascularization procedure. This suggests wound size and infection burden are the driving factors behind the elevated risk in this group.”

According to the study investigators, the decision to perform revascularization in a patient with critical limb ischemia must be made carefully, particularly given their often extensive list of comorbidities.

This study supports the use of the WIfI system to predict which diabetic patients with critical limb ischemia might best be served by revascularization and highlights the importance of multidisciplinary teams for complex medical and surgical patients, concluded the investigators in the SVS press release.