- Critical limb ischemia (CLI), defined as ischemic pain at rest (Rutherford Category 4) or minor tissue loss of the limb (Rutherford Category 5), and with either toe artery occlusive pressure < 50 mmHg or TBI ≤ 0.5 or ankle artery occlusion pressure ≤ 60 mm Hg or ABI ≤ 0.5