Presenting limb severity is associated with long-term outcomes after infrainguinal revascularization for chronic limb-threatening ischemia
- Type of Research: Single-center retrospective cohort study
- Key Findings: Among 413 patients undergoing infrainguinal revascularization for CLTI, long-term risk of major amputation was associated with presenting WIfI stage (p<0.001). Autogenous vein bypass provided > 80% freedom from major amputation at 2 years, even among those with WIfI stage 4 disease.
- Take Home Message: Presenting WIfI stage is associated with long-term risk of major amputation. In patients who are surgical candidates, autogenous vein bypass provided durable limb salvage, particularly in those presenting with WIfI stage 4 disease.
The SVS Wound, Ischemia, foot Infection (WIfI) limb staging system was established to estimate risk of major amputation in chronic limb-threatening ischemia (CLTI) and better stratify outcomes comparisons. There is little data on treatment outcomes beyond one year based on presenting WIfI stage.
This is a single-institution retrospective study of 413 patients who underwent infrainguinal revascularization for CLTI (2011-2021) with data available for WIfI staging. Patient characteristics and outcomes were gathered from the electronic medical record. Data were analyzed based on presenting WIfI stage and initial treatment received at our center.
Presenting WIfI stages were 1-2 (23%), 3 (27%) and 4 (50%). Index revascularization approach was endoluminal (59%), autogenous vein bypass (29%), or non-autogenous bypass (13%). Operative mortality within 30 days was 2.9% and was not associated with WIfI stage or revascularization approach. Median limb follow-up time was 502 days (IQR 112-1256), and median survival follow-up time was 932 days (IQR 343-1770). Major amputation or death occurred in 19% and 46% of patients at median times of 119 days (IQR 28-314) and 739 days (IQR 204-1475), respectively. WIfI stage was independently associated with major amputation (p=0.001), as was initial revascularization approach (p=0.01). In a Cox proportional hazards model, factors independently associated with major amputation were male sex [HR 1.4 (1.04-2.0), p=0.03], diabetes [HR1.8 (1.3-2.5), p=0.001], WIfI stage 4 [HR 2.3 (1.5-3.5), p<0.001], and non-autogenous bypass [HR 2.9 (2.1-4.2) p<0.001]. In a Cox proportional hazards model for mortality, independently associated factors were age [HR 1.04 (1.02-1.05), p<0.001], ESRD [HR 2.8 (1.9-4.0), p<0.001], CHF [HR 1.9 (1.4-2.5), p<0.001], COPD [HR 1.5 (1.1-2.1, p=0.02), and WIfI stage 4 [HR 1.6 (1.04-2.2), p=0.03].
Among those presenting with WIfI stage 4 limbs, Kaplan-Meier estimated rates of freedom from major amputation or death at 2 years were 71% ± 3.7% and 68% ± 3.5%, respectively. In an inverse propensity weighted Cox proportional hazards model, non-white race [HR 1.5 (1.01-2.2), p=0.047], diabetes [HR 2.0 (1.2-3.3), p=0.008], GLASS IP grade [HR 1.2 (1.05-1.3), p=0.005], non-autogenous bypass [HR 3.2 (1.9-5.3), p<0.001], and endoluminal revascularization [HR 2.6 (1.6-4.3), p<0.001] were independently associated with major amputation in the WIfI stage 4 subgroup.
Presenting WIfI stage is strongly associated with long-term risks of major amputation and death following infrainguinal revascularization for CLTI and should be used to stratify outcomes comparisons. Effective revascularization is critical in WIfI stage 4 disease, and autogenous vein bypass provides durable long-term limb preservation.