WIfI Classification — Wound, Ischemia, Foot Infection System for Peripheral Arterial Disease

The Wound, Ischemia, and foot Infection (WIfI) classification system is a validated, evidence-based staging framework developed by the Society for Vascular Surgery (SVS) to standardize risk assessment for patients with lower extremity peripheral arterial disease (PAD) with threatened limb status. WIfI replaces older classifications (Fontaine, Rutherford) for critical limb ischemia (CLI) by incorporating three independent determinants of amputation risk: (1) Wound severity, (2) Ischemia degree, and (3) foot Infection presence/severity. Combined WIfI staging (0–4) predicts 1-year amputation risk and benefit from revascularization, enabling more accurate limb salvage planning.