Heat Therapy to Reduce Pain and Improve Walking Tolerance

Not Applicable

Completed

Conditions: Peripheral Arterial Disease

Registration Number: NCT03435835

Lead Sponsor: Indiana University

Brief Summary: The purpose of this study is to investigate whether exposure to heat therapy improves calf muscle oxygenation and enhances walking tolerance in patients with symptomatic Peripheral Arterial Disease (PAD).

Detailed Description: 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 study is to establish evidence to support the validity of HT in improving walking tolerance on PAD patents.

Subjects will complete baseline assessments for eligibility, including medical history and ankle-brachial measurement. Eligible participants will be asked to report to the laboratory on 4 different occasions. The purpose of visits 1 and 2 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. is to familiarize the participants with the treadmill walking test and assess the test-retest reliability of maximal walking time determination. On visits 3 and 4 participants will receive either heat treatment or a control treatment for 80 min prior to undergoing a symptom-limited incremental test on the treadmill.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 19

Inclusion Criteria

Men and women with stable symptomatic leg claudication for 6 months or longer.
Ankle brachial index < 0.9

Exclusion Criteria

Heart Failure
COPD
Critical limb ischemia
Prior amputation
Exercise-limiting co-morbidity
Recent infrainguinal revascularization or planned during study period
Plans to change medical therapy during duration of the study
Active cancer
Chronic kidney disease
HIV positive, active HBV or HCV disease
Presence of any unsuitable comorbid clinical condition in the opinion of the PI
Peripheral neuropathy, numbness or paresthesia in the legs
Morbid obesity, BMI > 36 or unable to fit in water-circulating pants
Open wounds or ulcers on the extremity
Unable to walk on the treadmill

Study & Design

Study Type: INTERVENTIONAL

Study Design: CROSSOVER

Primary Outcome Measures

Name	Time	Method
Peak Walking Time	Immediately after exposure to a single session of heat therapy or sham treatment, up to ~20 min	Exercise testing was performed in a motorized treadmill (Pro 27, Woodway, St. Paul, Minnesota, United States) following the Gardner-Skinner protocol, which consists of walking at a constant speed (2 mph) with a 2%-grade increase every 2 min (Gardner et al., 1991). Participants received standardized instructions and were asked to indicate when they first began to feel leg pain with a "thumbs up" signal (defined as COT), and then give a "thumbs down" signal when they could no longer continue with the test (defined as PWT).

Secondary Outcome Measures

Name	Time	Method
Peak Diastolic Blood Pressure	The exercise test was performed immediately after exposure to a single session of either heat therapy or sham, up to ~20 min	Blood pressure was measured in the left arm using a stethoscope and sphygmomanometer prior and during exercise
Peak Calf Tissue Saturation Index	The exercise test was performed immediately after exposure to a single session of either heat therapy or sham, up to ~20 min	The tissue saturation index (TSI%) of the most symptomatic leg was assessed with a commercially available NIRS system (Portamon, Artinis Medical Systems, The Netherlands).
Peak Systolic Blood Pressure	The exercise test was performed immediately after exposure to a single session of either heat therapy or sham, up to ~20 min	Blood pressure was measured in the left arm using a stethoscope and sphygmomanometer during exercise.
Claudication Onset Time	The exercise test was performed immediately after exposure to a single session of either heat therapy or sham, up to ~20 min	Exercise testing was performed in a motorized treadmill (Pro 27, Woodway, St. Paul, Minnesota, United States) following the Gardner-Skinner protocol, which consists of walking at a constant speed (2 mph) with a 2%-grade increase every 2 min (Gardner et al., 1991). Participants received standardized instructions and were asked to indicate when they first began to feel leg pain with a "thumbs up" signal (defined as COT), and then give a "thumbs down" signal when they could no longer continue with the test (defined as PWT).
Post-exercise Plasma Endothelin-1 Concentration	The exercise test was performed immediately after exposure to a single session of either heat therapy or sham, up to ~20 min. Ten minutes following completion of the incremental treadmill test, blood samples were obtained for the assessment of serum ET-1	Commercially available enzyme-linked immunosorbent assay kits were used to measure the plasma concentrations of ET-1 (DET100, Endothelin-1 Quantikine ELISA Kit, R\&D Systems, Minneapolis, MN, United States)