Far Red Light to Improve Functioning in PAD

NCT ID: NCT06165016

Last Updated: 2025-08-26

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: NA
• Total Enrollment: 32 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2024-02-14
• Study Completion Date: 2027-06-01

Brief Summary

The LIGHT PAD Trial is a Phase II multi-centered randomized clinical trial to collect preliminary data to test whether daily far red light treatment of the lower extremities in people with PAD improves six-minute walk distance, lower extremity perfusion, and ischemia-related damage in gastrocnemius muscle at four-month follow-up, compared to a sham control. Participants will complete 10 minutes of twice daily home treatment with either far red light or a sham light for four months.

Detailed Description

The LIGHT PAD Trial is a Phase II multi-centered randomized clinical trial to collect preliminary data to test whether daily far red light treatment of the lower extremities in people with PAD improves six-minute walk distance, lower extremity perfusion, and ischemia-related damage in gastrocnemius muscle at four-month follow-up, compared to a sham control. Participants will complete 10 minutes of twice daily home treatment with either far red light or a sham light for four months.

Participants with PAD will be randomized at one of two centers: Northwestern University (PI: MM McDermott, MD) and the University of Alabama (PI: Nicole Lohr MD, PhD) to daily far red light or sham control for four months. The primary outcome, change in six-minute walk, will be measured at four month follow-up, immediately after the final administration of far red light or sham. In secondary and exploratory aims, investigators will distinguish between acute and chronic effects of far red light on six-minute walk, measure the effects of far red light on patient-reported outcomes, and delineate biologic pathways by which far red light improves walking performance in PAD, by measuring change in plasma nitrite and nitrosothiols, gastrocnemius muscle perfusion (MRI arterial spin labeling) and gastrocnemius muscle health and mitochondrial activity. If the proposed hypotheses are supported by this Phase II trial, results will be used to design a definitive randomized trial of far red light for people with PAD.

To achieve the specific aims, investigators will randomize 32 participants age 50 and older with PAD to one of two groups: far red light therapy or sham therapy. Participants will be followed for four months.

Conditions

Peripheral Artery Disease; Peripheral Vascular Disease; Aging; Walking, Difficulty

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: TRIPLE

Study Groups

Far red light therapy

Subgroup of participants receiving the 670 nm far red light device

Group Type: EXPERIMENTAL

Far red light therapy

Intervention Type: DEVICE

All participants will receive one far red light device per leg. Participants will be asked to use their two light devices daily, exposing their bare legs to the devices for 10 minutes twice per day. A study coordinator will deliver the light devices to each participant's home, positioning the devices 15 cm behind the participant's heels, using tape on the floor to mark where the light and feet should be positioned. Twice each day, the participant flips a switch on the device to begin each session. A timer will turn off the device after 10 minutes. A power meter will measure the total time that the device was turned on. Participants will also record use of the light in a log.

Sham therapy

Subgroup of participants receiving the sham light device, far red light device covered with blue filter paper to block 670 nm light, resulting in mean power generated of 0.24 mW/cm2, compared to 26.3 mW/cm2 for the intervention, a 100-fold difference.

Group Type: SHAM_COMPARATOR

Sham light therapy

Intervention Type: DEVICE

All participants will receive one sham device per leg. Participants will be asked to use their two light devices daily, exposing their bare legs to the devices for 10 minutes twice per day. A study coordinator will deliver the light devices to each participant's home, positioning the devices 15 cm behind the participant's heels, using tape on the floor to mark where the light and feet should be positioned. Twice each day, the participant flips a switch on the device to begin each session. A timer will turn off the device after 10 minutes. A power meter will measure the total time that the device was turned on. Participants will also record use of the light in a log.

Interventions

Far red light therapy

All participants will receive one far red light device per leg. Participants will be asked to use their two light devices daily, exposing their bare legs to the devices for 10 minutes twice per day. A study coordinator will deliver the light devices to each participant's home, positioning the devices 15 cm behind the participant's heels, using tape on the floor to mark where the light and feet should be positioned. Twice each day, the participant flips a switch on the device to begin each session. A timer will turn off the device after 10 minutes. A power meter will measure the total time that the device was turned on. Participants will also record use of the light in a log.

Intervention Type: DEVICE

Sham light therapy

All participants will receive one sham device per leg. Participants will be asked to use their two light devices daily, exposing their bare legs to the devices for 10 minutes twice per day. A study coordinator will deliver the light devices to each participant's home, positioning the devices 15 cm behind the participant's heels, using tape on the floor to mark where the light and feet should be positioned. Twice each day, the participant flips a switch on the device to begin each session. A timer will turn off the device after 10 minutes. A power meter will measure the total time that the device was turned on. Participants will also record use of the light in a log.

Intervention Type: DEVICE

Eligibility Criteria

Inclusion Criteria

First, all participants will be age 50 and older. Second, all participants will have PAD. PAD will be defined as:

1. An ABI <= 0.90 at baseline.

2. Vascular lab evidence of PAD (such as a toe brachial pressure =< 0.70 or an ankle brachial index less than or equal to 0.90), or angiographic evidence of PAD defined as at least 70% stenosis of an artery supplying the lower extremities.

3. An ABI of >0.90 and <= 1.00 who experience a 20% or greater drop in ABI in either leg after the heel-rise test.

Exclusion Criteria

1. Above- or below-knee amputation

2. Critical limb ischemia defined as an ABI <0.40 with symptoms of rest pain

3. Wheelchair confinement or requiring a walker to ambulate

4. Walking is limited by a symptom other than PAD

5. Current foot ulcer on bottom of foot

6. Failure to successfully complete the study run-in

7. Planned major surgery, coronary or leg revascularization during the next four months

8. Major surgery, coronary or leg revascularization or major cardiovascular event in the previous three months

9. Major medical illness including lung disease requiring oxygen, Parkinson's disease, a life-threatening illness with life expectancy less than six months, or cancer requiring treatment in the previous two years. [NOTE: potential participants may still qualify if they have had treatment for an early stage cancer in the past two years and the prognosis is excellent, unless the cancer is located in the lower extremities. Participants who require oxygen only at night may still qualify.]

10. Mini-Mental Status Examination (MMSE) score < 23

11. Non-English speaking

12. Participation in or completion of a clinical trial in the previous three months. [NOTE: after completing a stem cell or gene therapy intervention, participants will become eligible after the final study follow-up visit of the stem cell or gene therapy study so long as at least six months have passed since the final intervention administration. After completing a supplement or drug therapy (other than stem cell or gene therapy), participants will be eligible after the final study follow-up visit as long as at least three months have passed since the final intervention of the trial.]

13. Visual impairment that limits walking ability.

14. Six-minute walk distance of <400 feet or >1700 feet.

15. Participation in a supervised treadmill exercise program or a cardiac rehabilitation program in previous three months or planning to begin a supervised treadmill exercise program or a cardiac rehabilitation program in the next five months.

16. Unwilling to avoid red light therapy outside of study participation.

17. Baseline blood pressure <100/45.

18. In addition to the above criteria, investigator discretion will be used to determine if the trial is unsafe or not a good fit for the potential participant.

• Minimum Eligible Age: 50 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Northwestern University

OTHER

Sponsor Role: lead

Responsible Party

Mary McDermott

Jeremiah Stamler Professor of Medicine

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

University of Alabama at Birmingham

Birmingham, Alabama, United States

Site Status: RECRUITING

Northwestern University

Chicago, Illinois, United States

Site Status: RECRUITING

Countries

United States

Central Contacts

Mary McDermott, MD

Role: CONTACT

mdm608@northwestern.edu

13125036419

Facility Contacts

Nicole Lohr, MD

Role: primary

nlohr@uabmc.edu

Mary McDermott, MD

Role: primary

mdm608@northwestern.edu

312-503-6419

Other Identifiers

STU00218660

Identifier Type: -

Identifier Source: org_study_id