Treatment of critical limb threatening ischemia (corresponding to Rutherford grade II or III) consists of revascularization of the leg with critically reduced blood supply. Depending on the localization and morphology of the occlusion, surgical revascularization by means of bypass surgery or catheter-based percutaneous transluminal angioplasty (PTA) may be used (even as a complementary procedure). However, successful revascularization is possible in only max. 60% to 70% of the patients affected. Patients with limb threatening ischemia which cannot be revascularized have a one-year amputation rate exceeding 80% and a 20-30% mortality.