The objective of this pilot study is to establish evidence to support the validity of HT in improving skeletal muscle function and physical capacity of patients with HFpEF. Our central hypothesis is that HT treatment will lead to improvements in skeletal muscle and microvascular function compared to a control intervention. As a result, we anticipate that patients treated with HT will demonstrate improved skeletal muscle microvascular blood flow and oxygenation resulting in enhanced exercise tolerance. To explore this hypothesis, we propose the following specific aim: Explore the effects of home-based HT on exercise tolerance in patients with HFpEF.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
90
A sous vide heating immersion circulator heats up the water inside the water tank to 42ºC. A water pump circulates temperature-regulated water through the trousers.
A sous vide heating immersion circulator heats up the water inside the water tank to 33ºC. A water pump circulates temperature-regulated water through the trousers.
IU Health Methodist
Indianapolis, Indiana, United States
RECRUITINGIU Health University Hospital
Indianapolis, Indiana, United States
RECRUITINGChange in time to exhaustion during treadmill exercise
The investigators will determine whether daily leg heat therapy for 90 min using water-circulating trousers perfused with water heated to 42ºC improves the time to exhaustion during treadmill exercise testing at 2-month follow-up compared to a sham treatment.
Time frame: Baseline to 2-month follow-up
Change in maximal pulmonary oxygen uptake during treadmill exercise
Maximal pulmonary oxygen uptake (VO2max) will be evaluated during treadmill exercise testing. The investigators will determine whether leg heat therapy improves VO2max at 2-month follow-up compared to the sham treatment.
Time frame: Baseline to 2-month follow-up
Change in triceps surae microvascular oxygenation during treadmill exercise
Microvascular oxygenation will be assessed using near-infrared spectroscopy (NIRS) during treadmill exercise testing. The investigators will determine whether leg heat therapy improves muscle microvascular oxygenation at 2-month follow-up compared to the sham treatment.
Time frame: Baseline to 2-month follow-up
Change in systolic blood pressure
The systolic blood pressure will be measured in triplicate using a blood pressure monitor. The investigators will determine whether leg heat therapy improves systolic blood pressure at 2-month follow-up compared to the sham treatment.
Time frame: Baseline to 2-month follow-up
Change in diastolic blood pressure
The diastolic blood pressure will be measured in triplicate using a blood pressure monitor. The investigators will determine whether leg heat therapy improves blood pressure at 2-month follow-up compared to the sham treatment.
Time frame: Baseline to 2-month follow-up
Change in Minnesota Living with Heart Failure Questionnaire (MLHFQ) score
Health-related quality of life will then be assessed via the MLHFQ, which is a validated, self-administered, 21-item disease-specific instrument for patients with heart failure. Items are scored in a 6-point Likert scale (0 to 5) and reflect physical, emotional and socioeconomic status during the past 4 weeks. The questionnaire is scored by summation of all 21 responses (with higher scores indicating poorer quality of life).
Time frame: Baseline to 2-month follow-up
Change in triceps surae microvascular oxygenation during reactive hyperemia
Microvascular oxygenation will be assessed using near-infrared spectroscopy (NIRS) during reactive hyperemia. The investigators will determine whether leg heat therapy improves muscle microvascular oxygenation at 2-month follow-up compared to the sham treatment.
Time frame: Baseline to 2-month follow-up
Change in triceps surae volume
The volume of calf muscles will be determined using magnetic resonance (MR) images. The investigators will determine whether leg heat therapy improves calf muscle volume at 2-month follow-up compared to the sham treatment.
Time frame: Baseline to 2-month follow-up
Change in triceps surae intramuscular fat content
The intramuscular fat content of calf muscles will be determined using magnetic resonance (MR) images. The investigators will determine whether leg heat therapy reduces intramuscular fat content at 2-month follow-up compared to the sham treatment.
Time frame: Baseline to 2-month follow-up
Change in the time constant for phosphocreatine recovery after dynamic exercise
Magnetic resonance spectroscopy tuned to phosphorous (31PMRS) will be used to measure the time constant for PCr recovery (τ) after dynamic planar flexion exercise. The investigators will determine whether leg heat therapy reduces the time constant for PCr recovery at 2-month follow-up compared to the sham treatment.
Time frame: Baseline to 2-month follow-up
Change in maximal plantar flexor strength
The maximal voluntary contraction (MVC) strength of the plantar flexor muscles will be assessed using an MR-compatible ergometer. Participants will be asked to perform three plantar-flexor MVCs separated by a one-minute rest period. The MVC torque will be considered the highest peak torque value measured over the three trials. The investigators will determine whether leg heat therapy improves maximal plantar flexor strength at 2-month follow-up compared to the sham treatment.
Time frame: Baseline to 2-month follow-up
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