Effect of Lower Leg Heating and Transcutaneous Electrical Nerve Stimulation on Exercise Capacity in Patients With PAD

Study Overview
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Brief Summary
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Peripheral arterial disease (PAD) is characterized by poor circulation in the lower extremities that often provokes claudication (leg pain, numbness, and heaviness) with physical exertion. The aim of this research protocol is to determine the effect of two non-invasive treatment modalities on leg blood flow and exercise capacity in those with PAD. Specifically, we are measuring popliteal artery blood flow (Doppler ultrasound), toe oxygen saturation, ankle-brachial index (ABI), and 6-minute walking distance (6MWD) in men and women who have intermittent claudication (Fontaine Stage II; Rutherford Category 1-2) in response to 15 or 45 minutes of lower limb heating and transcutaneous electrical nerve stimulation (TENS).

Official Title
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The Acute Effects of Leg Heating and Transcutaneous Electrical Nerve Stimulation on Leg Blood Flow and Functional Capacity in Those With Peripheral Arterial Disease

Conditions
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Peripheral Arterial Disease

Intervention / Treatment
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* Behavioral: Lower leg heating
* Behavioral: Lower leg transcutaneous electrical nerve stimulation (TENS)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Intermittent claudication (Fontaine Stage II) Resting ankle-brachial index (ABI) < 0.90 Ability to walk > 60 meters in six minutes Exclusion Criteria: Body mass index (BMI) > 35 kg/m2 Severe exercise limitations (more than PAD) due to co-morbidity Taking illegal/recreational drugs Uncontrolled hypertension (>180/100 mmHg) Severe peripheral neuropathy Foot ulcers Gangrene Pregnant or breast feeding

Ages Eligible for Study
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Minimum Age: 40 Years
Maximum Age: 85 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: Supportive Care
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: 15 minute lower leg heating<br> | Behavioral: Lower leg heating<br>* Immersion of lower legs in a circulating water bath at a temperature of 42 degrees Celsius<br>|
| Experimental: 45 minute lower leg heating<br> | Behavioral: Lower leg heating<br>* Immersion of lower legs in a circulating water bath at a temperature of 42 degrees Celsius<br>|
| No Intervention: Control<br> | |
| Experimental: 15 minute lower leg TENS<br> | Behavioral: Lower leg transcutaneous electrical nerve stimulation (TENS)<br>* Bilateral lower leg transcutaneous electrical nerve stimulation (TENS) using burst mode at a 3Hz burst rate, 100Hz frequency, and 250 µs pulse duration, sufficient to evoke skeletal muscle contraction<br>|
| Experimental: 45 minute lower leg TENS<br> | Behavioral: Lower leg transcutaneous electrical nerve stimulation (TENS)<br>* Bilateral lower leg transcutaneous electrical nerve stimulation (TENS) using burst mode at a 3Hz burst rate, 100Hz frequency, and 250 µs pulse duration, sufficient to evoke skeletal muscle contraction<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Distance walked during six-minute walk test | Distance walked during a self-paced six-minute walk | 35 minutes post-intervention/control | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Popliteal artery blood flow | Unilateral popliteal blood flow measured via Doppler ultrasound | Pre-intervention baseline; 10, 20, and 30 minutes post-intervention/control | 
| Time/distance to claudication during six-minute walk | Subjects give subjective ratings of claudication onset, if applicable, during six-minute walk test | 35 minutes following each intervention and control period | 
| Ankle brachial index (ABI) | Systolic blood pressures (SBP) are measured in the brachial arteries of both arms and in the posterior tibial and dorsalis pedis arteries of both ankles using a hand-held Doppler ultrasound probe and a sphygmomanometer | Pre-intervention baseline and 20 minutes post-intervention/control | 
| Toe oxygen saturation | A pulse oximeter is used to measure toe oxygen saturation in the big toe of each of the subject's feet | Pre-intervention baseline; 10, 20, and 30 minutes post-intervention/control |