This trial aims to compare the effect of the patient's own blood stem in treating patients with severe peripheral arterial disease. The trial is being conducted at the Alfred Hospital in Melbourne and proposes to recruit 20 subjects. The subjects will be randomly assigned to two groups. They will either receive a single injection of CD 34+ stem cells via the limb artery (experimental group) or a placebo injection (control group). Participants will be monitored for complications and assessed for changes in their clinical condition.