Safety and Efficacy of Autologous Bone Marrow Stem Cells for Lower Extremity Ischemia Treating

Inclusion Criteria: * Critical lower limb ischemia, defined as ischemic pain at rest and / or the presence of minor tissue loss, with the possibility of healing. * Failure of conventional medical treatment and attempts to open or percutaneous revascularization before, with an observation period of two months after the last attempt at revascularization. * Patients considered at high risk for new revascularization procedure by at least two independent observers. Exclusion Criteria: * Expected life span less than six months * Large tissue loss in the ischemic limb indicating the need for limb amputation in the short term. * Evidence of osteomyelitis in the ischemic extremity. * Current or previous history of neoplasia. * Unstable angina, recent stroke or other medical condition that contraindicate anesthesia for bone marrow aspiration. * Proliferative retinopathy. * Debilitating disease with a life span less than one year. * Myelofibrosis, myelodysplasia or other diseases that affect the bone marrow. * Use of alcohol in excess of twice-daily doses or history of illicit drug use. * Need for continuous high doses of drug therapy with steroids (more than 7.5 mg/day). * Positivity for HIV or syphilis