The target population consists of patients suffering from critical limb ischemia (CLI) lasting more than 2 weeks. CLI is defined as rest pain or tissue loss (Fontaine stages III-IV or Rutherford classes 4 to 6) and/or ankle-brachial index < 0.40. Patient with acute limb-threatening ischemia, bone fractures in the relevant areas, nonatherosclerotic disease (e.g. arteriitis) and documented hypercoagulable diseases will be excluded from this study. There will be no experimental or control groups. The comparison groups will be: