Society for Vascular Surgery limb stage and patient risk correlate with outcomes in an amputation prevention program.

OBJECTIVE: Clinical decision making and accurate outcomes comparisons in advanced limb ischemia require improved staging systems. The Society for Vascular Surgery Lower Extremity Threatened Limb Classification System (Wound extent, Ischemia, and foot Infection [WIfI]) was designed to stratify limb outcomes based on three major factors-wound extent, ischemia, and foot infection. The Project or Ex-Vivo vein graft Engineering via Transfection III (PREVENT) III (PIII) risk score was developed to stratify patients by expected amputation-free survival (AFS) after surgical revascularization. This study was designed to prospectively assess limb and patient-based staging for predicting outcomes of hospitalized patients in an amputation prevention program.

METHODS: This study undertook a retrospective analysis of prospectively gathered registry data of consecutive patients with limb-threatening conditions admitted to a fully integrated vascular/podiatry service over a 16-month period. Upon admission, limb risk was stratified using the WIfI system and patient risk was categorized using PIII classification. Patients were assessed for perioperative and postdischarge outcomes, and their relationship to staging at admission was analyzed.

RESULTS: There were 174 threatened limbs (143 hospitalized patients) stratified by WIfI stage (1%-12%, 2%-28%, 3%-24%, 4%-28%, 5%-3%, unstaged-5%) and PIII risk (34% low, 49% moderate, and 17% high risk). Diabetes and end-stage renal disease were associated with WIfI stage (P = .006 and P = .018) and PIII risk (P = .003 and P < .001). Perioperative (30-day) events included 3% mortality, 8% major adverse cardiovascular events and 2.4% major amputation. There were 119 limbs (71%) that underwent revascularization, including 108 infrainguinal reconstructions (endovascular or open revascularization). Rate of revascularization increased with WIfI stage (P < .001), concomitant with the number of podiatric procedures, minor amputations, and initial hospital duration of stay (all P < .001). Increased WIfI stage was associated with major adverse limb events (P = .018), reduced limb salvage (P = .037), and decreased AFS (P = .048). In contrast, PIII risk category was associated with mortality (P < .001) and AFS (P < .001). Among infrainguinal reconstruction procedures, there was a similar distribution of endovascular (46%) and surgical (54%) interventions. Freedom from major adverse limb events was best for autogenous vein bypass (P = .025), and surgical revascularization was associated with improved limb salvage among the most severely threatened limbs (WIfI stage 4: 95% limb salvage for open bypass vs 68% limb salvage for endovascular; P = .026).

CONCLUSIONS: Among patients hospitalized with limb-threatening conditions and treated by a multidisciplinary amputation prevention team, PIII risk correlates with mortality whereas WIfI stage strongly predicts initial hospital duration of stay, and key mid-term limb outcomes. Surgical revascularization performed best in the limbs at greatest risk (WIfI stage 4), and autogenous vein bypass was the preferred conduit for open bypass. These data support the use of WIfI and PIII as complementary staging tools in the management of chronic limb-threatening ischemia.