The objective Study is to evaluate the short- and long-term clinical outcomes of patients receiving the CryoVein cryopreserved saphenous vein allograft (CVA) as their primary open bypass conduit to assess if there is a quantifiable correlation to time of placement as a primary bypass graft and improved long-term clinical outcomes of patients with critical limb ischemia (CLI).

A minimum of 50 CVA will be implanted in enrolled patients at up to 6 participating sites. The Study will include prospective evaluations on these patients at discharge, 1, 3, 6, 9, 12, 18 and 24 months following surgery. The window for follow-up visits is ± 2 weeks for each time point. All Study patients will be expected to participate in all follow-up evaluations unless precluded by patient death.

Patient status and graft performance data will be collected on all patients consented and enrolled into the Study. The primary endpoint of the Study will be limb salvage. The secondary endpoints of the Study will include primary patency, secondary patency, morbidity and mortality per the same reporting standards.

Patient attributes (age, gender, etc.) and preoperative assessments (indication for surgery, medical history) will be summarized using descriptive statistics. Graft performance will be presented as freedom from an event endpoint (patient death, graft complication, amputation, graft explant) as calculated by the Kaplan-Meier method. Log Rank and Cox Regression will be utilized for comparison between subgroups of the patient population. Statistical software will be used to compile and analyze all submitted clinical data.

The method of data reporting may include, but is not limited to, a description of the sample population, frequency distributions of patient demographics, allograft statistics, and follow-up percentages, summary of event data, correlation analysis, and actuarial analysis

Inclusion Criteria:

• Patient is an acceptable candidate to receive primary open bypass on the limb receiving the CVA.
• CLI diagnosis of Rutherford Class 5 or 6.
• Tibio-peroneal trunk, Tibial or Peroneal outflow artery.
• Minimum of 1 patent run-off artery.
• Serum Creatinine < 2.4 mg/dl.
• Life expectancy > 2 years from consent.
• 18 years of age or older at the time of consent.
• Male or non-pregnant female.
• Ability to understand and provide written informed consent.
• Willing and able to attend and cooperate with the follow-up examinations.
• Able to follow Study required post-operative daily aspirin and/or other oral anticoagulation/antiplatelet regimen.

Exclusion Criteria:

• Patient currently receiving hemodialysis for end stage renal disease.
• Known hypercoaguable state.
• Known heparin allergy.
• Patients with any condition which, in the opinion of the investigator could preclude evaluation of response or completion of follow-up or affect patient safety.
• Currently being treated with an investigational device or drug (within 3 months prior to surgery).

Patients presenting with Rutherford Class 5 or 6 CLI that are being evaluated for open peripheral arterial revascularization.

Post market study of 361 product; not supporting any FDA approvals.