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

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).

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 StO₂ (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.

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 StO₂ increased in controls and T2D but remained below baseline in PAD (p < 0.001).

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.