Influence of Lower Limb Ischemia on Skeletal Muscle Mass Depletion in Patients with Peripheral Artery Disease

The aim of the study was to determine the change in skeletal muscle mass over time by bioelectrical impedance analysis (BIA) in patients with peripheral artery disease (PAD).Patients with symptomatic PAD visiting Tokyo Medical University Hospital between January 2018 and October 2020 were retrospectively analyzed. PAD was diagnosed based on ankle brachial pressure index (ABI) < 0.9 with either leg and confirmed by duplex scan and/or computed tomography angiography as needed. Patients undergoing endovascular treatment, surgery, or supervised exercise therapy were excluded before and during the study period. Skeletal muscle mass of the extremities was measured using BIA. The sum of skeletal muscle masses in the arms and legs was calculated as skeletal muscle mass index (SMI). Patients were scheduled to undergo BIA at an interval of 1 year.Of 119 patients, 72 patients were included in the study. All patients were ambulatory and had symptoms of intermittent claudication (Fontaine's stage II). SMI significantly decreased from 6.98 ± 1.30 at baseline to 6.83 ± 1.29 at 1-year follow-up. Individual skeletal muscle mass of the ischemic leg was significantly reduced after 1 year, but not in the nonischemic leg. A decrease in SMI (defined as SMI ≥0.1 kg/m2 per year) was independently associated with low ABI. The optimal cut-off value of ABI for the decrease in SMI was 0.72.These results suggest that lower limb ischemia due to PAD, especially if ABI is < 0.72 or less, may result in a decrease in skeletal muscle mass that affects health and physical function.