The purpose of the study is to assess the efficacy of a novel 8 week heat therapy intervention in intermittent claudication compared to usual care controls. Participants will be enrolled on a wait-list control randomised trial testing physiological, mechanistic, and health related outcome measures.
70 participants with PAD will be randomised into one of two groups: either wait-list controls (usual care) or heat therapy intervention. The 8 week heat therapy intervention will consist of shoulder depth submersion in a hot tub at \~40°C for three times a week. Time for heating will be graded with aim of \~60 minutes submersion time by the end of the intervention. After 8 weeks the wait-list control group will then enrol onto the heat intervention and heat therapy participants will go back to usual care. The primary outcome measure for the study is improvement in maximum walking distance, pain free walking, and time to onset claudication. This will be measured via a graded exercise test. Secondary outcomes include Quality of life as measured by generic and vascular specific questionnaires (SF-36,VascuQoL and EQ-5D-5L), vascular health measured using ABPI, blood pressure, FMD, PWV, and markers of inflammation, oxidative stress, angiogenesis and vascular remodelling will be assessed from blood samples. All aforementioned outcome measures will be taken at baseline, 8 weeks, and 16 weeks. Physical activity behaviour (measured with an accelerometer) will be monitored 7 days prior to the beginning of the study, 7 days prior heat intervention, and 7 days after heat intervention.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
70
Heat Therapy Intervention of shoulder depth submersion in a 40°C hot tub.
Manchester Metropolitan University
Manchester, United Kingdom
Maximum Walking Distance
Maximal walking distance a participant can walk, through a graded treadmill test.
Time frame: Baseline to 8 weeks to 16 weeks
Pain Free Walking Distance
Maximum distance participant can walk without pain (IC)
Time frame: Baseline to 8 weeks to 16 weeks
Time for Onset of Claudication
Amount of time able to walk pain free before reaching claudication
Time frame: Baseline to 8 weeks to 16 weeks
VascuQoL-6
Quality of life was assessed using the Vascular Quality of Life Questionnaire (VacQoL), a disease-specific instrument comprised of 25 items rated on a 7-point Likert scale. When scored as a mean across items, the VacQoL has a range from 1 to 7, where 1 indicates the poorest quality of life and 7 the best. Alternatively, when summed, the total score ranges from 25 (worst) to 175 (best).
Time frame: Baseline to 8 weeks to 16 weeks
SF-36
The Short Form 36 Health Survey Questionnaire (SF-36) is used to indicate the health status of particular populations, to help with service planning and to measure the impact of clinical and social interventions.
Time frame: Baseline to 8 weeks to 16 weeks
EQ-5D-5L
The EQ-5D-5L is a brief, multi-attribute, generic, health status measure composed of 5 questions with Likert response options (descriptive system) and a visual analogue scale. The latter asks patients to rate their own health from 0 to 100 (the worst and best imaginable health, respectively).
Time frame: Baseline to 8 weeks to 16 weeks
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Markers of Inflammation
Investigators will compare blood sample measures of TNF-α, CRP, MCP-1, IL-1Ra, IL-4, IL-6, IL-8, IL-10, and eHSP70.
Time frame: Baseline to 8 weeks to 16 weeks
Markers of Vascular Remodelling
Investigators will compare blood sample measures of HIF-1α, VEGF, endothelin-1, MMP-9, MMP-10 and nitrite.
Time frame: Baseline to 8 weeks to 16 weeks
Tissue Oxygenation
Superficial tissue oxygen saturation and muscle oxygen consumption will be measured throughout the protocol by a NIRS probe placed on the skin surface of the medial gastrocnemius on the most affected leg. Measurements will be recorded during the graded treadmill test.
Time frame: Baseline to 8 weeks to 16 weeks
Vascular Ultrasound Imaging
Vascular ultrasound images of the carotid, brachial and superficial femoral artery will be obtained using a high-resolution duplex machine (Terason, Burlington, MA) and subsequently used to calculate wall thickness, changes in arterial blood flow and shear stress.
Time frame: Baseline to 8 weeks to 16 weeks
Flow-Mediated Dilation
Flow-mediated dilation (FMD) of the brachial artery will be measured after 10 min of supine rest via reactive hyperemia in response to transient ischemia of the lower arm according to international guidelines.
Time frame: Baseline to 8 weeks to 16 weeks
Ankle-Brachial Pressure Index
Ankle brachial pressure index (ABPI): ABPI will be determined at rest and following a treadmill test by using standardised methodologies
Time frame: Baseline to 8 weeks to 16 weeks
Blood Pressure
Following a 10-minute period of supine rest in a quiet room, blood pressure will be measured (in duplicate) using an automated sphygmomanometer.
Time frame: Baseline to 8 weeks to 16 weeks
Pulse Wave Velocity and Pulse Wave Analysis
Pulse wave velocity will be measured using central (carotid-femoral) and peripheral (carotid-radial) via a handheld tonometer following standard guidelines. This will be used with a SphygmoCor XCEL.
Time frame: Baseline to 8 weeks to 16 weeks
Physical Activity Levels
Physical activity will be measured using a wrist-worn accelerometer. Physical activity will be monitored for 7 days at a time. This including 7 days pre-trial, 7 days pre heat intervention, 7 days post heat intervention, and 7 days post trial (Dependent on what group randomisation was first).
Time frame: 7 days prior trial, 7 days prior heat intervention, 7 days after heat intervention, 7 days post trial.