Plantar Foot Microvascular Reactivity and Oxygenation in Type 2 Diabetes and Peripheral Artery Disease: An Exploratory Study

Objective Microvascular dysfunction contributes to foot complications in type 2 diabetes (T2D) and peripheral artery disease (PAD), yet has been characterized primarily in non‐plantar regions. We evaluated microvascular reactivity and oxygenation at ulcer‐prone plantar sites and responses to combined heat therapy and intermittent pneumatic compression (HT + IPC). Methods Forty adults ≥ 50 years (Control n = 20, T2D n = 11, PAD with or without T2D n = 9) were studied. Plantar hallux CVC (laser Doppler flux/MAP) and forefoot StO 2 (near‐infrared spectroscopy) were measured during local heating and reactive hyperemia. Responses to 60‐min HT + IPC were evaluated using the contralateral foot as a control. Results At the plantar hallux, the increase in %CVCmax from baseline to the initial peak was attenuated in PAD compared with controls and T2D ( p < 0.01), whereas plateau responses were similar. At the forefoot, PAD showed faster deoxygenation during ischemia and slower reoxygenation during reactive hyperemia ( p < 0.01). During HT + IPC, popliteal blood flow increased similarly across groups; however, plantar StO 2 increased in controls and T2D but remained below baseline in PAD ( p < 0.001). Conclusions These preliminary findings indicate impaired plantar microvascular function in a heterogeneous PAD cohort, most of whom also had T2D. Larger studies are needed to confirm these findings and to elucidate the underlying mechanisms.