PROJECT SUMMARY Diabetes mellitus (DM) is a common condition (34M in USA). Approximately 1 in 7 DM patients have diabetic foot ulcers (DFU). Approximately half of patients with DFU have concomitant peripheral arterial disease (PAD), resulting in US prevalence of 2.5M patients with ischemic or neuroischemic DFUs. Patients with DFUs experience recurrent hospitalizations, chronic wound healing issues, and ultimately amputations that severely limit quality of life and productivity and place a significant burden of care on families and a sizable cost for the healthcare system. The patients with DFUs experience either some bone removal (750K to 1.35M ) or amputation (170K) annually, making new options necessary to treat these patients and prevent the costly amputations and hospitalizations. Patients with DFU’s who also have PAD experience these symptoms because of poor blood flow both in the larger arteries delivering blood to the lower leg and in the smaller vessels branching out to supply the muscles and tissues of the lower leg and foot. Acoustic energy modalities such as therapeutic ultrasound (TUS) have been shown to promote collateral vessel growth, angiogenesis, and to improve perfusion in animal models of coronary artery disease and PAD, with promising early human data in both disease processes. Vibrato Medical has developed a novel treatment with the first wearable therapeutic ultrasound (TUS) device for the non-invasive, outpatient treatment of PAD that will promote collateral vessel growth and angiogenesis, restore perfusion and reduce amputation rates. We have already demonstrated VibratoSleeve’s efficacy in markedly improving lower extremity perfusion in healthy volunteers using multiple perfusion measures. The goal of this Phase I SBIR proposal is to conduct a prospective open-label clinical trial designed to evaluate the acute improvement in perfusion to ischemic or neuro-ischemic DFUs. A total of 12 subjects will receive wearable VibratoSleeve treatment to the posterior calf for 90 minutes at 3 separate clinic visits at low, medium and high acoustic intensity settings. Efficacy will be assessed by comparing baseline and on- therapy, and mean improvements in each endpoint will be compared across all 3 intensities to determine a dose-response relationship. We will also systematically obtain patient feedback on ease of use, tolerability, and comfort of VibratoSleeve using a standardized questionnaire administered after each 90-minute treatment. Data on the tactile sensation and comfort will inform optimal acoustic parameters, treatment duration and design of a subsequent sham-controlled clinical trial of long-term TUS therapy to assess DFU healing.