Pedal Arch and Angiosome Classification Combined with the Wound, Ischaemia, and foot Infection Staging System for Prediction of Limb Amputation and Wound Healing in Chronic Limb-Threatening Ischemia: A Prospective Cohort Study.

OBJECTIVE: To evaluate whether a three-group foot arch and angiosome classification adds independent predictive value for limb amputation and wound healing duration when combined with the Wound, Ischaemia, and foot Infection (WIfI) staging system in patients with chronic limb-threatening ischemia (CLTI) using seven prespecified predictive models. DESIGN: Prospective observational cohort study. METHODS: Eighty-nine consecutive CLTI patients were enrolled from a tertiary vascular center over 12 months. Each patient underwent WIfI staging (low or high risk) and was assigned to one of three foot arch groups: Group A (complete pedal arch or incomplete arch with direct angiosome supply to the wound), Group B (incomplete arch with indirect angiosome supply, or absent arch with inflow from the same angiosome territory as the wound), or Group C (absent arch with no direct angiosome supply). Foot arch classification was performed on completion DSA following revascularization. Seven prespecified binary predictive models were evaluated, including WIfI alone, two foot-arch only models, and four serial or parallel combinations. Diagnostic indices including overall accuracy were computed, and multivariable logistic and linear regression were performed with adjustment for age, sex, smoking status, diabetes mellitus, hypertension, ischemic heart disease, and renal insufficiency. RESULTS: Mean age was 61 ±9 years; 76.4% were male. Limb salvage was achieved in 69 patients (77.5%); 20 underwent amputation (22.5%). The serial combination of high WIfI risk AND foot arch Groups B or C achieved the highest overall accuracy (0.781; 95% confidence interval [CI], 0.681 - 0.862), with sensitivity 75.0%, specificity 81.2%, positive predictive value 53.6%, and negative predictive value 91.8%; adjusted odds ratio (OR), 15.951 (95% CI, 3.952-64.372; P < 0.001). WIfI alone yielded adjusted OR, 27.968 (95% CI, 3.381-231.35; P = 0.002). Foot arch Group C alone yielded adjusted OR, 5.969 (95% CI, 1.719-20.727; P = 0.005). Both high WIfI risk (B = 1.334; P < 0.001) and high foot arch risk (B = 1.037; P = 0.001) independently predicted prolonged wound healing duration. Smoking was the only baseline characteristic associated with amputation (75.0% vs 42.0%; P = 0.009). CONCLUSIONS: Pedal arch and angiosome assessment provide additional prognostic information beyond WIfI staging alone in patients with CLTI. Incorporating these parameters into risk assessment may improve prediction of both limb loss and wound healing outcomes. Patients with concurrent high WIfI risk and compromised pedal arch status demonstrated the greatest risk of adverse outcomes and may benefit from escalated wound care, closer surveillance consideration of repeat intervention following revascularization.