Muscle Oxygenation During Exercise in Patients with Peripheral Artery Disease: A Systematic Review

Peripheral artery disease (PAD) involves atherosclerotic obstruction of the leg arteries and impairs function and structure of lower-limb tissues. Although traditionally regarded as a large-artery (macrovascular) disorder, PAD includes significant microvascular disease in the affected musculature, together leading to impaired leg perfusion. Monitoring muscle oxygenation during exercise provides an indirect index of limb perfusion and exercise capacity, and tracking its kinetics with near-infrared spectroscopy (NIRS; a portable, non-invasive technique measuring real-time tissue oxygen saturation) helps elucidate mechanisms underlying walking limitations in PAD. We systematically searched PubMed, Web of Science, and the Cochrane Library (1985-2025) for studies employing NIRS to monitor muscle oxygenation in PAD patients before, during, and after exercise. Of 628 articles screened, 11 met the inclusion criteria. NIRS demonstrated reliability and validity for monitoring muscle oxygenation in PAD. During walking, PAD patients showed a much steeper decline in muscle oxygenation and delayed recovery to baseline. Resting muscle oxygenation did not differ between patients with PAD and controls. These dynamics reveal the pathophysiological interplay in which proximal/macrovascular and distal/microvascular disease limit oxygen delivery and utilization in skeletal muscle. Accordingly, NIRS offers a sensitive, non-invasive tool to evaluate macro- and microvascular disease burden and monitor therapeutic response in PAD.