Intravascular Ultrasound for Peripheral Artery Disease Revascularization

Inclusion Criteria: 1. Patients presenting with lower extremity PAD manifesting as CLTI: a. CLTI is defined as ischemic rest foot pain, nonhealing wounds, or gangrene present for at least two weeks and that is attributable to objectively proven arterial occlusive disease, compatible with Rutherford class 4, 5 or 6, with the following supporting hemodynamic criteria1: i. For ischemic rest pain (Rutherford category 4): Ankle systolic pressure \< 40mmHg, toe pressure \< 30mmHg, or flat-line transtarsal pulse volume recording, OR ii. For tissue loss (Rutherford category 5, 6): Ankle systolic pressure \< 60 mmHg, toe pressure of \< 40mmHg, or flat-line transtarsal volume recording, AND 2. Scheduled to undergo percutaneous revascularization, AND 3. Informed consent 4. Imaging evidence of an obstructive or occluded lesion (\> 70%) in the infraiguinal circulation (e.g. femoral, popliteal, or infrapopliteal circulation) using angiography, ultrasound, computed tomography, or magnetic resonance imaging. 5. An infrapopliteal lesion must be located in the proximal 2/3 of native infrapopliteal vessels, with a vessel diameter of \> 2.5mm by investigator visual assessment. 6. The distal margin of the most distal target lesion must be located \> 10 cm proximal to the proximal margin on the ankle mortise. The vessel segment distal to the most distal target lesion must be patent all the way to the ankle, with no obstructive lesion (\>50% stenosis). Exclusion Criteria: 1. The presence of anatomic or comorbid conditions or other medical, social, or psychological conditions that, in the investigator's opinion, could limit the potential participant's ability to participate in the trial or to comply with the follow-up requirements. 2. The presence of any medical conditions precluding percutaneous revascularization 3. The subject has previously had or requires surgical revascularization involving the vessel containing the target lesion of the ipsilateral extremity. 4. The subject is bedridden or unable to walk (with assistance is acceptable). 5. Life expectancy \< 12 months 6. Age \< 18 years 7. Active vasculitis, Buerger's disease, or acute limb-threatening ischemia 8. Planned above-ankle amputation of the index limb within four weeks of the index procedure. 9. Obstructive supra-inguinal "inflow" (\>70% stenosis) which is not planned to be treated during index procedure or within 30 days of the index procedure. 10. The subject has had any amputation to the ipsilateral extremity other than the toe or forefoot, or the subject has had a major amputation to the contralateral extremity \< 1 year before the index procedure and is not independently walking. 11. Extensive tissue loss that is salvageable only with complex foot reconstruction or non-traditional trans metatarsal amputations. 1. Osteomyelitis that extends proximal to the metatarsal heads 2. Gangrene involving the plantar skin of the forefoot, midfoot or heel 3. Deep ulcer or large shallow ulcer (\> 3 cm) involving the plantar skin of the f forefoot, midfoot, or heel 4. Full-thickness heel ulcer 5. Any wound with calcaneal bone involvement 6. Wounds that would require flap coverage or complex wound management for large soft tissue defect 7. Full-thickness wounds on the dorsum of the foot with exposed tendon or bone.