Heat Therapy for Peripheral Arterial Disease (HEATPAD)

Peripheral arterial disease (PAD) is a disabling condition, with symptoms of muscle cramping or pain on exertion, which can substantially reduce quality of life. This study aims to see if AirGlove device improves participants circulation. This is phase 1 study and will be taken in 3 parts: Phase 1a will be undertaken in 10 healthy volunteers to assess the effects of the AirGlove device on lower limb arterial flow, tissue perfusion, quality of life and product usability following a single session. Phase 1b will be undertaken in 20 participants with intermittent claudication to assess the effects of the AirGlove device on lower limb arterial flow, tissue perfusion, quality of life and product usability both in a single session and following a 12-week trial of heat therapy. Phase 1c will be undertaken in 10 participants with critical limb ischaemia Rutherford stage 4 (rest pain). Lower limb arterial flow, tissue perfusion, pain scores, quality of life, and product usability will be assessed both in a single session and following a 2-12 week trial of heat therapy.

As people get older, the blood supply to the legs can get worse. This is caused by blockages in the main blood vessels in the leg. If left to get worse this can progress to ulcers and amputation. If treated early the blood supply can be improved. Currently patients are advised to exercise to improve their blood supply, however not all patients can do this. Recent work has shown that heat treatment could have a benefit in these patients to help improve walking distance and lower the risk of amputation. The studies so far have been limited to a one-off treatment, typically to the whole body rather than the affected leg. This study aims to use a device to warm the lower leg for a set amount of timeper day. The research team will look at the improvement in their walking distance and blood supply to the leg over a 12 week period.

The first phase of this study will be in healthy volunteers. They will undergo the trial protocol in a single session to assess acceptability of the trial protocol and identify potential barriers.

All patients invited into this study will be given the heat therapy device called AirGlove. This slides over the lower leg like a large sock, and hot air circulates within the sock itself. The research team will teach the patient how to use the device and they will then take it home for 12 weeks. At the start and end of the study patients will undergo tests to assess their walking distance, quality of life, pain, and to assess how much blood is getting down their leg.

This study will look at the role of heat therapy as an alternative to help improve their walking, potentially reducing the need for surgery, and saving legs.

Eligibility Criteria:
Participants in Phase 1a will be healthy volunteers. The inclusion criteria for this cohort are:

* Aged 18 or over
* ABPI within normal range (0.9 - 1.2)
* Negative Edinburgh Claudication Questionnaire

For Phase 1b and 1c inclusion criteria are:

* Capacity to provide informed consent
* Aged 60 or over
* ABPI \<0.9
* Positive Edinburgh Claudication Questionnaire

Exclusion Criteria:

* Aged under 60 years (for Phase 1b and 1c only)
* Has known allergy to any trial product
* undergone previous surgical or endovascular intervention for peripheral arterial or endovascular intervention for peripheral arterial disease
* Alternative cause of leg pain
* Requires urgent revascularisation (\<2 weeks)
* Significant leg ulceration/necrosis