Home-Based Lower-Extremity Heat Therapy for Walking Function in Peripheral Artery Disease

Lower-extremity peripheral artery disease is associated with impaired walking ability, reduced lower-extremity function, exercise intolerance, and decreased quality of life. Reduced physical function in individuals with peripheral artery disease can limit daily activity and contribute to progressive mobility loss. This randomized, sham-controlled clinical trial will evaluate the effects of 12 weeks of home-based lower-extremity heat therapy on walking function, lower-extremity performance, blood pressure, and quality of life in adults with peripheral artery disease.

A total of 40 participants with peripheral artery disease will be enrolled and randomized to active lower-extremity heat therapy or sham therapy. Eligible participants will include men and women older than 45 years with a resting ankle-brachial index of less than 0.90 and greater than 0.40 in at least one leg. Participants will be excluded for conditions that may interfere with safe participation or outcome assessment, including critical limb ischemia, ischemic rest pain, ischemia-related non-healing wounds or tissue loss, prior amputation, major exercise-limiting comorbidity, recent lower-extremity revascularization or orthopedic surgery, use of a walking aid other than a cane, active treatment for cancer, severe chronic kidney disease, class 2 or 3 obesity, or inability to use the study treatment system as intended.

Participants will complete baseline study visits that include informed consent, resting ankle-brachial index measurement, familiarization with study procedures, and baseline assessment of walking function and lower-extremity performance. Baseline outcome measures will include the six-minute walk test, assessment of calf strength and fatigability using isokinetic dynamometry, the Short Physical Performance Battery, and blood pressure measurement.

After completion of baseline assessments, participants will be randomized to one of two study groups using a blocked randomization scheme stratified by sex. Participants assigned to the active therapy group will complete daily 90-minute home-based lower-extremity heat therapy sessions for 12 weeks. Participants assigned to the sham therapy group will complete the same treatment schedule using a lower-temperature sham condition designed to preserve participant blinding while minimizing the expected physiological effects of active heat therapy.

Outcome assessments will be repeated at week 6 and week 12. To evaluate chronic rather than acute responses to treatment, participants will be instructed to interrupt therapy 48 hours before follow-up outcome visits. The primary outcome is the change in six-minute walk distance from baseline to 12 weeks. Secondary outcomes include changes in leg strength and fatigability, Short Physical Performance Battery score, blood pressure, and patient-reported quality of life.

• Peak plantar flexor and knee extensor power [Time frame: 12 weeks]
• Plantar flexor and knee extensor resistance to fatigue [Time frame: 12 weeks]
• Short Physical Performance Battery (SPPB) score [Time frame: 12 weeks]
• Walking Impairment Questionnaire (WIQ) [Time frame: 12 weeks]