Home-based Leg Heat Therapy

Study Overview
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Brief Summary
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The objective of this study is to evaluate the benefits of participating for 8 weeks in a home-based daily treatment with heat therapy (HT) or a thermoneutral control intervention, as assessed by vascular function, walking tolerance and quality of life.

Detailed Description
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Heat therapy (HT) is an emerging non-invasive approach that has been shown to enhance vascular function of the leg in old individuals. The objective of this randomized, controlled study is to evaluate the benefits of participating for 8 weeks in a home-based daily treatment with heat therapy (HT) or a thermoneutral control intervention, as assessed by vascular function, walking tolerance and quality of life. The central hypothesis of this study, based on preliminary data, is that exposure to HT will enhance the oxygenation of calf muscles during exercise and as a result, the onset of pain will be delayed and walking performance will be enhanced. The duration (8 weeks) was chosen based on the recent report of Brunt and co-workers that the improvement in endothelial function promoted by repeat HT in sedentary individuals peaks at 8 weeks following the onset of treatment. Heat Therapy will be applied daily for 90 minutes using water-circulating 'pants' connected to a water pump. Outcomes will be assessed at the halfway point (end of week 4), at the completion of the intervention (end of week 8) and 4 weeks after the end of the intervention (week 12).

Official Title
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Home-based Leg Heat Therapy for Patients With Symptomatic Peripheral Arterial Disease

Conditions
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Peripheral Arterial Disease

Intervention / Treatment
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* Device: Control/Sham Treatment
* Device: Heat Therapy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Men and women with a stable symptomatic PAD for ≥6 months Ankle brachial index <0.9 in at least one leg Age between 40 and 80 years Exclusion Criteria: Uncontrolled Diabetes (HbA1C > 8.5 measured within 3 months prior to date of consent) Wheelchair bound Use of a walking aid (i.e. cane, crutches, walker, motorized chair) Critical limb ischemia (ischemic rest pain or ischemia-related non healing wounds or tissue loss Impaired thermal sensation in the legs Exercise-limiting comorbidity Chronic Heart Failure stages C and stage D (Stage C: structural heart disease is present and symptoms have occurred; Stage D: presence of advanced heart disease with continued heart failure symptoms requiring aggressive medical therapy) Morbid obesity BMI > 35 or unable to fit into water-circulating pants Open wounds or ulcers on the extremity Prior amputation Lower extremity revascularization, major orthopedic surgery, cardiovascular event, or coronary revascularization in the previous three months Planned revascularization or major surgery during the next six months Plans to change medical therapy during the duration of the study Active treatment for cancer Chronic kidney disease (eGFR <30 by MDRD or Mayo or Cockcroft-Gault formula). HIV positive, active HBV or HCV disease. Presence of any clinical condition that makes the patient not suitable to participate in the trial. Unable to walk on the treadmill

Ages Eligible for Study
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Minimum Age: 40 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Patients were randomized (blocked and stratified by sex) using assignments generated from PROC PLAN in SAS Version 9.4 by the study statistician into one of two groups: those receiving leg heat therapy or those receiving the sham treatment.
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Sham Comparator: Sham treatment<br>Participants were dressed in water-circulating trousers that are connected to a pump. Water at 91.4 degrees F was circulated through the pants for 90 minutes daily for 8 weeks.. | Device: Control/Sham Treatment<br>* Thermoneutral water will be circulated through water-circulating trousers to maintain skin temperature at baselines levels daily for 90 minutes for 8 weeks.<br>|
| Active Comparator: Heat Therapy<br>Participants were dressed in water-circulating trousers that are connected to a pump. Water at 110 degrees F will be circulated through the pants for 90 minutes daily for 8 weeks. | Device: Heat Therapy<br>* Water at 110 degrees F will be circulated through water-circulating trousers daily for 90 minutes for 8 weeks.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in 6-min Walk Distance | Change in 6-min walk distance from baseline to the 8-week follow-up | 8 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Treadmill Peak Walking Time | Change in treadmill peak walking time from baseline to 8-week follow-up | 8 weeks | 
| Change in Peak Calf Blood Flow | Change in peak calf blood flow during reactive hyperemia from baseline to the 8-week follow-up | 8 weeks | 
| Change in Leg Cutaneous Vascular Conductance | Change in cutaneous vascular conductance from baseline to the 8-week follow-up | 8 weeks | 
| Change in the Vascular Quality of Life Questionnaire-6 Score | Change in Vascular Quality of Life Questionnaire-6 score from baseline to the 8-week follow-up. The total VASCUQOL score is the average score of questions answered and ranges from 1 (worst QOL) to 7 (best QOL) | 8 weeks | 
| Change in the Short Form 36 Physical Functioning Score | Change in the physical functioning subscale score from baseline to the 8-week follow-up. Each item is scored on a 0 to 100 range so that the lowest and highest possible scores are 0 and 100, respectively. Scores represent the percentage of total possible score achieved. A high score defines a more favorable health state. | 8 weeks |