Atherosclerotic occlusive disease resulting in lesions of the femoral N and infrapopliteal arteries is a common and prevalent condition in vascular surgery and is also clinically referred to as arteriopathy distal to the inguinal ligament. It can lead to intermittent claudication and severe limb ischemia (usually Fontaine Class III and IV, Rutherford Class 4 to 6) in the lower extremities. Compared with occlusive lesions of the main iliac artery, lesions of the arteries distal to the inguinal ligament have a thin arterial diameter, anatomical presence of transarticular sites, low pressure, poor outflow tract, and multi-segmental nature with extensive multivessel involvement. Cheng Wei, Department of Vascular Surgery, Beijing Anzhen Hospital For patients with intermittent claudication, stenosis or occlusion of the superficial femoral artery is the most common cause of intermittent claudication. The deep femoral artery and N artery are mostly richly established with collateral circulation, and isolated superficial femoral artery occlusion rarely causes further ischemia. the rate of severe clinical deterioration (20%) and amputation (5%) over 3 to 5 years is relatively low, so the main goal of interventional treatment is to improve the quality of life. Cases of severe limb ischemia are more often seen in sub-knee artery lesions and are due to extensive vascular involvement and lack of collateral circulation beyond these lesions. The prognosis of severe limb ischemia is much worse than that of intermittent claudication, with a reported amputation rate of 25% within 1 year and an additional 25% of patients dying from cardiovascular complications. Therefore, inguinal ligament to distal arterial lesions is a difficult point of vascular surgery treatment. Treatment】 1. Smoking is known to be a chronic irritant to atherosclerosis and has the risk of increasing the incidence of peripheral vascular disease in both men and women. The severity of arterial obstruction disease is directly proportional to the number of cigarettes smoked. Therefore, smoking cessation is necessary to slow down the progression of the disease and improve the patency rate after arterial reconstruction. 2. Functional exercise The best initial treatment for intermittent claudication is through planned exercise training. The benefits of this therapy go beyond the relief of claudication symptoms. Regular aerobic training can reduce the risk of cardiovascular disease by improving insulin sensitivity, lowering blood pressure, and lowering cholesterol levels. Cycling or walking is the most effective form of exercise for claudication, and resistance training may be effective in patients with comorbid other cardiovascular disease, but only as a supplement to walking, not as a substitute. 30 to 45 minutes 3 to 4 times per week, for no less than 12 weeks per session. At each training session, the patient should be encouraged to persist until the pain becomes unbearable, then take a short break to allow the pain to ease, and then continue to repeat the training. The cycle should continue with each exercise session, and as the pain-free walking interval increases, the intensity of the training should also gradually increase, increasing the grade and/or speed of the bicycle to increase the exercise load and ensure adequate pain stimulation during the training session. As walking capacity increases, some cardiac signs and symptoms may appear (e.g. arrhythmia, angina pectoris, ST-segment depression), which should be re-evaluated by a clinician. (1) Patients with severe limb ischemia have higher rates of concomitant diseases such as hypertension, coronary artery disease, diabetes mellitus and arrhythmias than patients with claudication, and consequently have higher 5-year mortality rates. Therefore, the diagnosis and treatment of concomitant diseases are particularly important. (2) Anti-platelet therapy Anti-platelet therapy does not improve the symptoms of lower extremity ischemia, but is of definite value in delaying the progression of atherosclerotic lesions and improving the patency rate after lower extremity arterial revascularization; aspirin at 75-325 mg/day also significantly reduces the risk of heart attack and stroke. Clopidogrel is an alternative to aspirin. In patients at very high risk, the combination of aspirin and clopidogrel may be effective, but the risk of bleeding needs to be evaluated. (3) Drug therapy to improve ischemic symptoms in the lower extremities Only 2 drugs (hexoketococine and cilostazol) are approved by the FDA as treatment for intermittent claudication. Other drugs include: nafuramate (5-hydroxytryptamine antagonist), levocanidine (increases substrate utilization for energy production at the molecular level of skeletal muscle metabolism), HMG-CoA reductase inhibitors (statins, which not only reduce the risk of death associated with stroke and myocardial infarction, but are also able to prolong claudication distance), and prostaglandins. Low-molecular heparin anticoagulation for acute critical limb ischemia is indeed clinically effective, but there is a lack of bulk clinical data to confirm this. 4. Surgical treatment includes various arterial bypass grafting and amputation. Arterial bypass grafting requires both good arterial inflow and outflow tracts. The graft vessels can be PTFE artificial vessels with support rings and autologous saphenous vein. Femoral-N artery bypass graft (above the knee) can be done with artificial vessels; below the knee bypass graft is mostly done with autologous saphenous vein. In situ saphenous vein bypass grafting is more suitable for the reconstruction of the distal N artery and tibial artery, which requires a valve knife to completely destroy the valve of the saphenous vein. The distal end can be anastomosed with the ankle or dorsalis pedis artery. Traditional surgical procedures are more invasive and have more complications. The long-term patency rate is poor. 5.Intraluminal therapy The patency rate of balloon dilation alone for long segment lesions is worse than that of surgery, but the limb preservation rate and long-term patency rate after stent implantation are equal to or even better than that of surgery; moreover, it has the advantage of being minimally invasive and can be repeatedly performed to deal with restenosis; intraluminal therapy can also reconstruct the arteries of the arch. Therefore, endoluminal therapy has increasingly become the treatment of choice for inferior peripheral inguinal artery disease. With the use of new devices, such as small-diameter long balloon catheters, minimally invasive plaque removal systems, blunt microdissection catheters, and endoluminal return catheter systems, new techniques, such as retrograde puncture opening of distal arteries, are widely used in clinical practice. This has greatly improved the opening rate, limb preservation rate and near and distant patency rate of diseased arteries. However, the long-term patency rate of endoluminal treatment is still unsatisfactory. Drug-coated balloons and stents and bioresorbable stents have been gradually used in clinical practice and are expected to significantly improve the long-term patency rate.