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).
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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
19
Water at 33ºC was circulated through water-circulating trousers.
Water at 42-43ºC was circulated through the water-circulating trousers.
Indiana University
Indianapolis, Indiana, United States
Peak Walking Time
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).
Time frame: Immediately after exposure to a single session of heat therapy or sham treatment, up to ~20 min
Claudication Onset Time
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).
Time frame: The exercise test was performed immediately after exposure to a single session of either heat therapy or sham, up to ~20 min
Peak Systolic Blood Pressure
Blood pressure was measured in the left arm using a stethoscope and sphygmomanometer during exercise.
Time frame: The exercise test was performed immediately after exposure to a single session of either heat therapy or sham, up to ~20 min
Peak Diastolic Blood Pressure
Blood pressure was measured in the left arm using a stethoscope and sphygmomanometer prior and during exercise
Time frame: The exercise test was performed immediately after exposure to a single session of either heat therapy or sham, up to ~20 min
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Peak Calf Tissue Saturation Index
The tissue saturation index (TSI%) of the most symptomatic leg was assessed with a commercially available NIRS system (Portamon, Artinis Medical Systems, The Netherlands).
Time frame: The exercise test was performed immediately after exposure to a single session of either heat therapy or sham, up to ~20 min
Post-exercise Plasma Endothelin-1 Concentration
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)
Time frame: 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