Peripheral Artery Disease, Peripheral Vascular Disease, Aging, Walking, Difficulty
Conditions
Keywords
light therapy
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.
Interventions
DEVICEFar 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.
DEVICESham 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.
Sponsors
Northwestern University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
TRIPLE (Subject, Caregiver, Outcomes Assessor)
Masking description
This will be a double blinded study where both the participant and the people collecting data will be blinded.
Intervention model description
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.
Eligibility
Sex/Gender
ALL
Age
50 Years to No maximum
Healthy volunteers
No
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Six-Minute Walk Distance | Measured at baseline and 4 month follow-up | Four month change in six-minute walk distance |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Walking Impairment Questionnaire Distance (WIQ) Score | Measured at baseline and 4 month follow-up | Four month change in the WIQ distance score. Score range 0-100, 100 is best |
| Six-Minute Walk Distance | Measured immediately after the first light treatment (within 15 minutes after the first treatment, acute effect) | Acute change in six-minute walk distance after first light therapy |
| Six-minute walk distance. | Measured at 4-month follow-up, 24 hours after the final treatment. | Four month change in 6-minute walk, measured 24 hours after last treatment. |
| Calf muscle perfusion | Measured at baseline and four-month follow up | Changes in calf muscle perfusion at 3 Tesla measured with arterial spin labeling with MRI and post-cuff occlusion hyperemia |
Other
| Measure | Time frame | Description |
|---|---|---|
| Gastrocnemius Muscle Abundance of Satellite Cells | Measured at baseline and four-month follow up | Four month changes in gastrocnemius muscle abundance of satellite cells |
| Gastrocnemius Muscle Abundance of Myofibers with Central Nuclei | Measured at baseline and four-month follow up | Four month changes in gastrocnemius muscle abundance of myofibers with central nuclei |
| Plasma nitrite | Measured before and within five minutes after the first light treatment | Acute change in plasma abundance of nitrite |
| Walking Impairment Questionnaire (WIQ) Stair Climbing Score | Baseline and four month follow-up | Four month changes in WIQ stair climbing score (0-100 score, 100-best). |
| Walking Impairment Questionnaire (WIQ) Speed Score | Baseline and four-month follow-up | Four month changes in the WIQ speed score (0-100 score, 100-best) |
| Plasma Nitrosothiols | Measured before and within five minutes after the first light treatment | Changes in plasma abundance of nitrosothiols |
| Gastrocnemius Muscle Capillary Density | Measured at baseline and four-month follow up | Four month changes in gastrocnemius muscle capillary density |
| Gastrocnemius Muscle Myofiber Size | Measured at baseline and four-month follow up | Four month changes in gastrocnemius muscle myofiber size |
| Gastrocnemius Muscle COX Enzyme Activity | Measured at baseline and four-month follow up | Four month changes in gastrocnemius muscle COX enzyme activity |
Countries
United States
Contacts
Primary ContactMary McDermott, MD
Outcome results
None listed