The purpose of this study is to evaluate the efficacy of dual intramuscular and intra-arterial autologous bone marrow mononuclear cell implantation for the treatment of patients with moderate to severe peripheral arterial disease in whom amputation was considered the only viable treatment option.

Study Hypothesis: Patients with moderate to severe peripheral arterial disease who receive intramuscular and intra-arterial stem cell injections will have improved ankle brachial index (ABI) measurements; relief of rest pain; ulcer healing, if applicable; and absence of major limb amputations.

Inclusion Criteria:

• Patients at least 18 years of age.
• Patients with moderate or severe limb-threatening PAD, defined as ankle brachial indices (ABI) less than 0.7 or presence of non-healing ischemic ulcers with stenosis or occlusion of two of the following lower extremity arteries: anterior tibial, posterior tibial, and peroneal.
• Patients with conditions that preclude recommendation of traditional endovascular or open bypass treatments.

Exclusion Criteria:

• Patients younger than 18 years of age.
• Patients who are eligible to undergo traditional endovascular or open bypass for the treatment of PAD.
• Female patients who are or may be pregnant.
• Patients who are prisoners.
• Patients with mental retardation or are unable to consent for participation independently.