An interventional study of Red Light (670 nm energy) and Octafluoropropane in Peripheral Artery Disease, Claudication, Intermittent and Vasodilation, sponsored by University of Alabama at Birmingham. Recruiting at 1 site in United States. Open to participants aged 18 Years to 85 Years. Per ClinicalTrials.gov, last updated 2026-05-01.
Sponsored by University of Alabama at Birmingham · Not applicable, Interventional, and Basic science
Subjects with a known diagnosis of peripheral artery disease as measured by an abnormal ankle brachial index (\<.9 or >1.1) will undergo a single 5 min exposure of 670 nm light, 1 cm above the gastrocnemius muscle. Blood flow will be measured by infusion of ultrasound contrast and subsequent acquisition of ultrasound images. 2 blood samples will be collected for measurement of nitric oxide metabolites.
The intent of this protocol is to measure blood flow in the gastrocnemius muscle in patients with documented peripheral artery disease before and after exposure to 670 nm light energy. The study consists of one visit. Blood flow measurement will be performed using contrast enhanced ultrasound, a method by which ultrasound contrast is continuously infused into the blood stream. Ultrasound records images in the area of interest and flow is related to the intensity of the contrast in each image. Blood will be drawn to measure nitric oxide metabolites. The study is designed to consist of one visit. However, if the protocol changes or the data quality initially collected is uninterpretable, subjects may be asked to return to allow for a standard methodology across all participants. In this case, the subjects who are asked to return will be subject to the same informed consent process a second time. The two visits will be at least one week apart to further reduce the already minimal risks of the study. This will also limit the number of study participants required to gather the necessary data to complete the study, thereby limiting the risks of the study to a smaller number of participants.
Diagnosis of peripheral artery disease is defined as an Ankle Brachial index of \<0.9 or greater than 1.1 either at rest or during treadmill exercise.
Exclusion Criteria:
This is a single arm design. All subjects will be enrolled to have peripheral blood flow measured before, during, and after red light exposure.
Device: Red Light (670 nm energy) · Drug: Octafluoropropane
Light Emitting Diode light source (670 nm wavelength with output up to 75mW/cm2) will be placed over the gastrocnemius muscle. The light will be on for 5 minutes.
All subjects will undergo infusion of octafluoropropane to measure peripheral blood flow.
Also known as: Definity
Changes in blood flow
Video intensity units from contrast images will be converted to ml/min/g tissue
Time frame: Baseline, 5 min of light, and up to 1 min after discontinuation of light
Changes in nitric oxide metabolites
NO measurement by ozone chemiluminescence
Time frame: Baseline and 1 min after discontinuation of light
Plan to share: No
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University of Alabama at Birmingham