Abstract
Fractional flow reserve (FFR), an established modality for functionally assessing coronary artery disease, is increasingly applied to diagnose and manage lower extremity arterial disease. By incorporating functional parameters, FFR enhances revascularization precision by quantifying the hemodynamic impact of stenotic lesions, thereby overcoming limitations of conventional imaging. Key clinical applications in lower extremity disease include functional assessment in moderate intermittent claudication, post-vascular preparation strategy optimization, and predicting revascularization outcomes and complications. Advances in pressure wire and microcatheter systems, alongside non-invasive imaging-derived FFR techniques, are improving its feasibility and applicability. However, widespread adoption is challenged by the complex anatomy of the lower extremity arterial system, frequent severe calcification and diffuse disease, and a current lack of standardized FFR cutoff values. Promoting the standardized use of FFR is crucial for shifting the clinical management paradigm from anatomy-based repair toward functional reconstruction.