Leg heat therapy improves perceived physical function but does not enhance walking capacity or vascular function in patients with peripheral artery disease.

A single session of leg heat therapy (HT) has been shown to elicit increases in leg blood flow and reduce blood pressure (BP) and the circulating levels of endothelin-1 (ET-1) in patients with symptomatic peripheral artery disease (PAD). We assessed whether 6 weeks of supervised leg HT (3 times/wk) using water-circulating trousers perfused with water at 48oC improved 6-minute walk distance in people with PAD, compared to a sham treatment. Secondary outcomes included the assessment of leg vascular function, BP, quality of life and the serum ET-1 and nitrite plus nitrate (NOx) levels. Of thirty-two PAD patients randomized, thirty (age: 68±8 yrs; ankle-brachial index (ABI): 0.6±0.1) completed the 3 and 6-week follow ups. Participants completed 98.7% of the treatment sessions. When compared to the sham treatment, exposure to HT did not improve 6-minute walk distance, BP, popliteal artery reactive hyperemia, cutaneous microvascular reactivity, resting ABI or the serum NOx levels. The change from baseline to 6 weeks in scores of the physical functioning subscale of the 36-item Short Form Health Survey was significantly higher in the HT group (Control: -6.9±10 versus HT: 6.8±15; 95% confidence interval: 2.5-24.3, p=0.017). Similarly, the change in ET-1 levels after 6 weeks was different between groups, with the HT group experiencing a 0.4 decrease (95% confidence interval: -0.8,-0.0, p=0.03). These preliminary results indicate that leg HT may improve perceived physical function in symptomatic PAD patients. Additional, larger studies are needed to confirm these findings and determine the optimal treatment regimen for symptomatic PAD patients.