SVS WIfI wound classification system for CLTI risk stratification

The Society for Vascular Surgery (SVS) Wound, Ischemia, and foot Infection (WIfI) classification system stratifies chronic limb-threatening ischemia (CLTI) risk by combining three domains: **Wound** (W0–3), **Ischemia** (I0–3), and **foot Infection** (fI0–3) to generate an overall limb threat stage (Stages 1–4). Higher WIfI stages correlate with increased 1-year amputation risk and greater potential benefit from revascularization. RecentThe scientificACC/AHA statementsguidelines fromon themanagement Americanof Collegelower ofextremity Cardiologyperipheral (ACC)artery disease (PAD) reinforce WIfI as the preferred classification system for risk stratification and clinical decision-making in adults with diabetes and CLTI [@acc2025-e].[@acc2026-e]. Objective ischemia thresholds include toe pressure (I0: ≥40 mmHg; I1: 30–39 mmHg; I2: <30 mmHg; I3: <30 mmHg with rest pain) and transcutaneous oxygen tension (TcPO₂; I0: ≥40 mmHg; I1: 30–39 mmHg; I2: <30 mmHg; I3: <30 mmHg with rest pain). WIfI should be documented at baseline and reassessed after revascularization to evaluate treatment response [@mills2014, @conte2019].

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**WIfI Limb Threat Stage Matrix**

| **WIfI Stage** | **1-Year Amputation Risk** | **Revascularization Benefit** |
| --- | --- | --- |
| 1 (Very low) | <5% | Low |
| 2 (Low) | 5–10% | Moderate |
| 3 (Moderate) | 10–20% | High |
| 4 (High) | >20% | Very high |