Skip to content

A New Heat Therapy Device for Home-based Leg Heating in Patients With Lower-extremity Peripheral Artery Disease

A New Heat Therapy Device for Home-based Leg Heating in Patients With Lower-extremity Peripheral Artery Disease: a Pilot Study

Status
Completed
Phases
Phase 1
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT05335161
Enrollment
6
Registered
2022-04-19
Start date
2023-05-30
Completion date
2024-02-07
Last updated
2025-08-15

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Intermittent Claudication, Peripheral Arterial Disease

Keywords

heat therapy, peripheral artery disease

Brief summary

The goal of the proposed pilot study is to evaluate the feasibility of a new leg heat therapy system treatment for patients with lower extremity PAD. The new system is comprised of leg-length water circulating pads surrounded by a separate pneumatic compression outer garment that compresses the pads against the skin for efficient heat transfer. The new leg garment is easily closed with a zipper. The air chambers automatically adjust the amount of air inflation enabling use of the garment independent of patient leg size. Six patients with PAD will be asked to complete daily (90 min/day) home-based leg HT for 12 weeks using the newly developed system. The primary study outcome is the change from baseline in walking performance on the 6-minute walk test at the 12-week follow-up. Secondary outcomes include plantar flexion power, as assessed using isokinetic dynamometry, sit-to-stand muscle power and perceived quality of life.

Detailed description

Lower-extremity PAD is a manifestation of systemic atherosclerosis associated with increased risk of cardiovascular morbidity and mortality, diminished quality of life, physical functioning and psychological well-being. In 2015, an estimated 236 million people worldwide, most between 65 and 69 years of age, were living with PAD. Home-based leg heat therapy (HT) is emerging as a potential effective and practical treatment to increase leg blood flow and improve walking performance in patients with symptomatic PAD. In the first randomized sham-controlled trial to examine the benefits of supervised leg HT in patients with symptomatic PAD (90 min, 3 days/week for 6 weeks), we demonstrated that patients assigned to the leg heating group displayed a clinically meaningful improvement in perceived physical functioning. Building upon these findings, we recently completed a NIH-sponsored randomized clinical trial to examine the safety, tolerability, and effectiveness of home-based, unsupervised leg HT (90 min, 7 days/week for 8 weeks) in 34 patients with symptomatic PAD. Patients randomized to the HT group displayed an increase in 6-minute walk from baseline of 23 meters after 8 weeks of treatment, which is clinically meaningful for PAD patients. Importantly, home-based leg HT was also found to be safe (no skin injury), well-tolerated, and patient compliance was surprisingly high (96% completion of the prescribed treatment sessions). Heat packs, electric heating pads, and electric blankets are widely available, but have high risk of contact burns, particularly in patients with peripheral neuropathy that is commonly associated with diabetes mellitus and PAD. An assembly of individual pads is difficult to apply and skin contact is unreliable. Water-circulating pads have been found to be safer than electric devices because they provide more reliable thermostatic control. PAD patients with diffuse bilateral disease often accompanied by neuropathy need a reliable system that is simple to operate, easy to put on, covers the entirety of both lower limbs and safely provides HT while avoiding skin injury. Currently, there is no commercially-available HT system for home-based therapy in elderly individuals, despite the documented benefits associated with repeated HT. To address this unmet clinical need, Aquilo Sports is developing a system that will monitor skin temperature and have an integrated shut-off feature to prevent skin burns, and record treatment sessions to confirm patient compliance. The system has undergone extensive independent validation testing and has been widely adopted by professional athletes. The garment is easily closed with a zipper and auto-adjusts pneumatically to different leg sizes. Our objective is to establish evidence to support the safety and feasibility of the redeveloped Aquilo system during repeated home-based treatment in patients with PAD. Our approach to testing our hypothesis will be to ask 6 patients with PAD to undergo daily home-based leg HT (90 min/day, 7 days/week) for 12 weeks. The length of the intervention (12 weeks) was selected as it is similar to: 1) the duration of previous studies with other HT modalities showing beneficial effects in patients with PAD, 2) the recommended minimal duration of exercise training interventions, the gold standard treatment for PAD. The primary study outcome is the change from baseline in walking performance on the 6-minute walk test at the 12-week follow-up. Secondary outcomes include plantar flexion power, as assessed using isokinetic dynamometry, sit-to-stand muscle power and perceived quality of life.The study coordinator will call patients weekly to record the occurrence of adverse events.

Interventions

The Aquilo system consists of a garment that contains an inner water-circulating pad that is compressed by air bladders. The volume of air inflating the air bladders is pressure-controlled so the garment automatically adjusts to the shape and size of all legs. The touch screen console contains pre-programmed settings for ease of use. After baseline characteristics are established, patients will be provided with the Aquilo device and will be instructed on how to operate the equipment and how to rapidly remove the system if the alarm sounds or if they have any unusual feeling. Patients in both groups will also receive a logbook to record their sessions. Patients will undergo daily home-based leg HT (90 min/day, 7 days/week) for 12 weeks. Water at 42ºC will be perfused through the water-circulating garment for 90 min, with the goal of increasing skin temperature in the calf to \ 37ºC.

Sponsors

Aquilo Sports
CollaboratorUNKNOWN
Purdue University
Lead SponsorOTHER

Study design

Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
DEVICE_FEASIBILITY
Masking
NONE

Intervention model description

Six patients with PAD will be asked to complete daily (90 min/day) home-based leg HT for 12 weeks using the newly developed system. Outcomes will be measured at baseline and at 12-week follow-up.

Eligibility

Sex/Gender
ALL
Age
60 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* Men and women 60 years or older * Resting ankle-brachial index (ABI) of 0.9 or less in at least one leg. * Individuals with a resting ABI between 0.91 and 1.00 at baseline will be eligible if their ABI drops by 20% or greater following a heel-rise test.

Exclusion criteria

* Critical limb ischemia (ischemic rest pain or ischemia-related, non-healing wounds or tissue loss) * Prior amputation * Exercise tolerance limited by factors other than leg pain (e.g. angina, arthritis, severe lung disease, etc). * Recent (\<3 months) lower-extremity revascularization or orthopedic surgery * Use of walking aid other than a cane * Active cancer * Chronic kidney disease (eGFR \<30 by MDRD or Mayo or Cockcroft-Gault formula) * Unable to fit into water-circulating trousers * A Mini-Mental Status Examination score \<23 * Impaired thermal sensation in the leg * Age lower than 60 yrs

Design outcomes

Primary

MeasureTime frameDescription
Change in Six-minute Walk DistanceBaseline to 12-week follow-upParticipants will receive standardized instructions and will be asked to walk the greatest distance possible by walking back and forth along a 100-ft corridor for 6 min.

Secondary

MeasureTime frameDescription
Change in Walking Impairment Questionnaire ScoreBaseline to 12-week follow-upThis disease-specific questionnaire assess the ability of patients with PAD to walk defined distances and speeds and to climb stairs, with scores ranging from 0 to 100. Higher scores indicate better walking ability (i.e., better outcome). Lower scores indicate greater walking impairment (i.e., worse outcome)
Device Usability Using the System Usability ScaleBaseline to 12-week follow-upScores range from 0 to 100; \> 70 represents acceptable usability.
Change in Triceps Surae Peak TorqueBaseline to 12-week follow-upTorque assessments of the plantar flexors will be performed using an isokinetic dynamometer. Participants will be asked to perform 3 maximal contractions.
Change in the Five Times Sit to Stand TestBaseline to 12-week follow-upParticipants were asked to sit in a chair with arms folded across their chest and stand five times consecutively as quickly as possible. The time it took to complete five chair rises was measured.

Countries

United States

Participant flow

Recruitment details

Device feasibility, safety, and usability were evaluated in an open-label, single-arm pilot study performed at Purdue University in West Lafayette, Indiana. Participants were provided the prototype HT device and were asked to apply the therapy daily (90 minutes, 7 days/week) for 12 weeks. The first participant was enrolled on May 30, 2023. The final follow-up occurred on February 7, 2024.

Pre-assignment details

Participants attended two baseline laboratory visits. No run-in or wash-out period was used, and no participants were excluded between enrollment and assignment.

Participants by arm

ArmCount
Home-based Leg Heat Therapy
Patients will be provided with the Aquilo heat therapy device and will be instructed on how to operate the equipment. The device will be used in accordance to the manufacturers recommendations. Patients will be asked to apply the therapy daily in the home setting for 12 week (90 min/day, 7 days/week).
6
Total6

Baseline characteristics

CharacteristicHome-based Leg Heat Therapy
Age, Categorical
<=18 years
0 Participants
Age, Categorical
>=65 years
4 Participants
Age, Categorical
Between 18 and 65 years
2 Participants
Race (NIH/OMB)
American Indian or Alaska Native
0 Participants
Race (NIH/OMB)
Asian
0 Participants
Race (NIH/OMB)
Black or African American
0 Participants
Race (NIH/OMB)
More than one race
0 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
0 Participants
Race (NIH/OMB)
Unknown or Not Reported
0 Participants
Race (NIH/OMB)
White
6 Participants
Region of Enrollment
United States
6 Participants
Sex: Female, Male
Female
2 Participants
Sex: Female, Male
Male
4 Participants

Adverse events

Event typeEG000
affected / at risk
deaths
Total, all-cause mortality
0 / 6
other
Total, other adverse events
0 / 6
serious
Total, serious adverse events
0 / 6

Outcome results

Primary

Change in Six-minute Walk Distance

Participants will receive standardized instructions and will be asked to walk the greatest distance possible by walking back and forth along a 100-ft corridor for 6 min.

Time frame: Baseline to 12-week follow-up

ArmMeasureValue (MEAN)Dispersion
Home-based Leg Heat TherapyChange in Six-minute Walk Distance32.3 MetersStandard Deviation 39
Secondary

Change in the Five Times Sit to Stand Test

Participants were asked to sit in a chair with arms folded across their chest and stand five times consecutively as quickly as possible. The time it took to complete five chair rises was measured.

Time frame: Baseline to 12-week follow-up

ArmMeasureValue (MEAN)Dispersion
Home-based Leg Heat TherapyChange in the Five Times Sit to Stand Test-1.93 SecondsStandard Deviation 2.55
Secondary

Change in Triceps Surae Peak Torque

Torque assessments of the plantar flexors will be performed using an isokinetic dynamometer. Participants will be asked to perform 3 maximal contractions.

Time frame: Baseline to 12-week follow-up

ArmMeasureValue (MEAN)Dispersion
Home-based Leg Heat TherapyChange in Triceps Surae Peak Torque4.49 NmStandard Deviation 6.33
Secondary

Change in Walking Impairment Questionnaire Score

This disease-specific questionnaire assess the ability of patients with PAD to walk defined distances and speeds and to climb stairs, with scores ranging from 0 to 100. Higher scores indicate better walking ability (i.e., better outcome). Lower scores indicate greater walking impairment (i.e., worse outcome)

Time frame: Baseline to 12-week follow-up

ArmMeasureValue (MEAN)Dispersion
Home-based Leg Heat TherapyChange in Walking Impairment Questionnaire Score11.08 score on a scaleStandard Deviation 16.79
Secondary

Device Usability Using the System Usability Scale

Scores range from 0 to 100; \> 70 represents acceptable usability.

Time frame: Baseline to 12-week follow-up

ArmMeasureValue (MEAN)Dispersion
Home-based Leg Heat TherapyDevice Usability Using the System Usability Scale49 score on a scaleStandard Deviation 11.98

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026