Optimized Strategy for Diabetic Patients With Critical Limb Ischemia(Part I)

Inclusion Criteria: * The patients volunteer to join the trial and sign the formal consent. * The patients are ≥55 year-old and ≤75 year-old. * The patients suffer from symptomatic leg ischemia with rutherford classification3, 4 , 5 or 6. The presentation is severe intermittent claudication, rest pain, ulcer or gangrene. * The lesion of the femoral artery should be TASC B、C or D. * The femoral-popliteal artery has never received bypass or endovascular therapy before. * No obvious stenosis or occlusion in the aortoiliac artery; or the lesion could be treated simultaneously or has already been cured. * No obvious stenosis in below-knee popliteal artery; at least 1 vessel infra-popliteal runoff to the foot. * No surgical contraindications;no infection in operation region. * Be diagnosed with DM for at least 1 year. Exclusion Criteria: * Refuse random treatment. * Previous operations on the superficial femoral artery. * Acute lower extremity arterial thrombosis. * Serious major organ failure. * Allergic to the contrast agent or has contrast nephropathy. * No clinical compliance or unfit to join the trial