- Patients presenting with Rutherford Classification 4 (ischemic rest pain), or Rutherford Classification 5 (minor tissue loss: non-healing ulcer, focal gangrene with diffuse pedal ischemia), or Rutherford Classification 6 (major tissue loss: extending above transmetatarsal level, functional foot no longer salvageable) at specialty clinics will prospectively be screened, regardless of whether the patient undergoes endovascular, bypass, amputation, and/or medical therapy.