- Presence of Critical Limb ischemia according to the guidelines of the Transatlantic Consensus Group (TASC) Rutherford grade II or III. Perfusion is measured with absolute perfusion pressure and ankle-brachial index (ABI) and transcutaneous oxygen tension (TcpO2); for inclusion, ABI has to be less than or equal to 0.6 or absolute ankle pressure must be less than 60 mmHg. If ABI is technically not feasible, e.g. in patients with media calcification, inclusion criteria are a tcpO2 value (supine, forefoot, 44°C) of less than 20 mmHg if there is no tissue loss, or a tcpO2 of less than 40 mmHg if there is tissue loss.