Fontaine Classification (PAD Severity) Calculator

Fontaine Classification (PAD Severity): Explanation and Clinical Context The Fontaine Classification is a widely used system to assess the severity of peripheral artery disease (PAD) based on clinical presentation of the lower extremities. It stratifies patients into four stages: Stage I (Asymptomatic): Patients have arterial narrowing without symptoms; often detected via ABI or imaging. Stage II (Intermittent Claudication): Pain occurs during walking and is relieved by rest; subdivided into IIa (>200 meters walking distance) and IIb (<200 meters).

Stage III (Rest Pain): Persistent ischemic pain at rest, often at night, indicating critical limb ischemia. Stage IV (Ulcer or Gangrene): Advanced ischemia with tissue loss, ulcers, or gangrene, representing the highest risk of limb loss. This tool aids clinicians in risk stratification, treatment planning, and monitoring disease progression, combining subjective symptoms with objective walking distance and tissue status.