Inclusion Criteria:

* Male or female, age 35 years or older
* Atherosclerotic, infrainguinal PAD
* CLI, defined as arterial insufficiency with gangrene, non-healing ischemic ulcer, or rest pain, consistent with Rutherford classes 4-6
* Candidate for either open or endovascular infrainguinal revascularization as judged by the treating investigators
* Adequate inflow into the index femoral artery
* Adequate popliteal, tibial, or pedal revascularization target
* Willing to comply with protocol, attend follow-up appointments, complete all study assessments, and provide informed consent
* Endovascular revascularization with a stent
* Surgical revascularization with a vein graft-

Exclusion Criteria:

* Femoropopliteal disease pattern consistent with TASC IIA
* Complete occlusion of the iliac artery
* Aortoiliac occlusive disease or severe common femoral artery disease
* Presence of a femoral, popliteal or tibial aneurysm of the index limb
* Life expectancy less than 2 years
* Deemed excessive risk for surgical bypass
* A vascular disease prognosis that includes an anticipated above ankle amputation on index limb within 4 weeks of index procedure
* Renal dysfunction defined as MDRD eGFR ≤ 30ml/min/173 m2 at the time of screening
* Currently on dialysis or history of a renal transplant
* A documented hypercoagulable state
* Nonatherosclerotic occlusive disease
* Any prior infrainguinal revascularization
* Current immuno-suppressive medication, chemotherapy or radiation therapy
* Absolute contraindication to iodinated contrast