The objective of this observational registry is to track the clinical progression of chronic limb-threatening ischemia (CLTI) and incidence of death, amputation, and revascularization attempts over a one-year period.

The objective of this observational registry is to track the clinical progression of chronic limb-threatening ischemia (CLTI) and incidence of death, amputation, and revascularization attempts over a one-year period.

The study population is comprised of Rutherford 5 and 6 CLTI subjects who have hemodynamic evidence of severely diminished arterial inflow of a peripheral limb and:

1. 2 revascularizations in the last 6 months that failed to resolve symptoms, OR
2. have inadequate popliteal, tibial, or pedal revascularization target

Inclusion Criteria:

1. Subject must be ≥18 years of age
2. Subject is Rutherford 5 or 6 classification with hemodynamic evidence of severely diminished arterial inflow of a peripheral limb and: a) 2 revascularizations in the last 6 months that failed to resolve symptoms, OR b) An inadequate popliteal, tibial, or pedal revascularization target
3. Subject is willing and able to sign the informed consent form and willing to participate in the phone follow-ups.

Exclusion Criteria:

1. Any significant concurrent psychological or social condition (e.g., no support person/network), which may significantly interfere with the subject's optimal participation in the study, in the opinion of the investigator.
2. Subject is participating in the PROMISE II Clinical Trial.

The study population is comprised of Rutherford 5 and 6 CLTI subjects who have hemodynamic evidence of severely diminished arterial inflow of a peripheral limb and:

1. 2 revascularizations in the last 6 months that failed to resolve symptoms, OR
2. have inadequate popliteal, tibial, or pedal revascularization target