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

Abstract

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 wk of supervised leg HT (3 times/wk) with water-circulating trousers perfused with water at 48°C improved 6-min walk distance in individuals with PAD compared with a sham treatment. Secondary outcomes included the assessment of leg vascular function, BP, quality of life, and serum ET-1 and nitrite plus nitrate (NOx) levels. Of 32 PAD patients randomized, 30 [age: 68 ± 8 yr; ankle-brachial index (ABI): 0.6 ± 0.1] completed the 3- and 6-wk follow-ups. Participants completed 98.7% of the treatment sessions. Compared with the sham treatment, exposure to HT did not improve 6-min walk distance, BP, popliteal artery reactive hyperemia, cutaneous microvascular reactivity, resting ABI, or serum NOx levels. The change from baseline to 6 wk 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 vs. HT 6.8 ± 15; 95% confidence interval: 2.5-24.3, P = 0.017). Similarly, the change in ET-1 levels after 6 wk was different between groups, with the HT group experiencing a 0.4 pg/mL 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. NEW & NOTEWORTHY: This is the first sham-controlled study to investigate the effects of leg heat therapy (HT) on walking performance, vascular function, and quality of life in patients with peripheral artery disease (PAD). Adherence to HT was high, and the treatment was well tolerated. Our findings revealed that HT applied with water-circulating trousers evokes a clinically meaningful increase in perceived physical function and reduces the serum concentration of the potent vasoconstrictor endothelin-1 in patients with PAD.