Peripheral arterial disease (PAD), whose main cause is atherosclerosis, can lead to narrowing or even occlusion of arteries in the lower or upper extremities and is part of systemic atherosclerosis. The disease presents with signs and symptoms of limb ischemia, mostly after the age of 60, and is significantly more common in men than women. In the United States, the prevalence is >5% in people >70 years of age. The lower extremity is much more involved than the upper extremity, with 30% of lesions involving the main hip artery, 80% to 90% of lesions involving the femoral carotid artery, and about 40% to 50% of lesions involving the tibio-fibular artery. Symptoms The main and typical symptoms are intermittent claudication and resting pain; local pain, tightness, numbness or weakness after limb movement, which is relieved after stopping movement is its characteristic. The site of pain is often associated with the diseased vessel; intermittent claudication due to pain in the buttocks, hips, and thighs often suggests partial obstruction of the aorta and iliac arteries. The most commonly seen clinical painful intermittent claudication in the lower leg is often femoral and carotid artery stenosis. Intermittent claudication in the ankle and toe is most often due to lesions in the tibial and peroneal arteries. Resting pain may occur when the lesion is further aggravated to the point of vascular occlusion. Signs 1. The distal artery pulsation disappears and a systolic murmur can be heard at the site of stenosis; if the distal collateral circulation is poorly formed resulting in low diastolic pressure, a continuous murmur can be heard. 2. Low temperature and malnutrition of the affected limb; thin, bright, pale skin, sparse hair, thickened toenails, edema, gangrene and ulcers in severe cases. 3, limb position change test; limb from elevated lowering to skin color turn red time > 10 seconds and superficial vein filling time > 15 seconds, suggesting arterial stenosis and poor side branch formation. Conversely, if the limb is elevated at an angle of 60°, if the skin color turns white within 60 seconds, it also indicates arterial stenosis. (a) Segmental blood pressure measurement A Doppler device is used to measure blood pressure in different arterial supply segments of the lower extremity. (b) Ankle-Brachial Index (ABI) measurement is a practical and accepted segmental blood pressure measurement of arterial stenosis in the lower extremities; the ABI is calculated by measuring the systolic pressure of the ankle and brachial arteries respectively with the corresponding width of the pulse strip. 0.5 was considered as severe stenosis. (c) Activity plate load test Objective evaluation of the blood supply status of the limb by the amount and time of exercise load at the appearance of ischemic symptoms, which is conducive to quantitative evaluation of the condition and the effect of therapeutic intervention. (iv) Doppler flow velocity curve analysis and Doppler ultrasound imaging As the degree of arterial stenosis increases, the flow velocity curve will flatten out, and the results will be more reliable when combined with ultrasound imaging. (e) Magnetic resonance angiography and CT angiography have positive diagnostic value. (f) Arteriography can visualize the vascular lesions and the status of collateral circulation, which can provide a direct basis for treatment decision of surgery or percutaneous intervention. Treatment (a) Medical treatment Actively intervene in the risk factors associated with the onset of the disease; quit smoking, control hypertension and diabetes, regulate lipids, etc. and take good care of the affected limbs; clean, moisturize, prevent trauma, and elevate the head of the bed for those with resting pain to increase blood flow to the lower limbs and reduce pain. 1.Walking exercise Encourage patients to adhere to walking 20-30 minutes / time, as many times a day as possible, can promote the establishment of collateral circulation, it is also believed that each walking time should be until the emergence of symptoms. 2.Anti-platelet therapy Aspirin or clopidogrel can inhibit platelet aggregation, which is effective for the progression of atherosclerotic lesions, and has been reported to reduce the mortality rate of cardiovascular disease coexisting with this disease by 25%. 3, the application of vasodilators No clear long-term efficacy, when the limb artery stenosis, in the exercise state, the distal vasodilation of its stenosis and the perfusion pressure of the tissue decreases, and the pressure between the tissues due to muscle movement can even exceed the perfusion pressure. The use of vasodilators at this time will exacerbate this contradiction, and unless the vasodilator can promote collateral circulation, it will not lead to improved perfusion of the exercising muscle. In other words, ischemic symptoms are unlikely to be relieved. Intravenous prostaglandin for severe limb ischemia may be effective in reducing pain and promoting healing of ulcers. 4.Other anticoagulants are ineffective, while thrombolytic agents are effective only when acute thrombosis occurs. (2) Reconstruction After active medical treatment, those who still have resting pain, tissue gangrene or severe quality of life reduction and disability can be treated by revascularization, including catheter intervention and surgical treatment; the former includes percutaneous balloon dilation, stent implantation and laser angioplasty. Surgical procedures include artificial vessels and autologous vascular bypass grafting, each with its own guidelines. Prognosis Since this disease is part of a systemic disease, its prognosis is closely related to the coexisting coronary heart disease and cerebrovascular disease. Angiography has confirmed that approximately 50% of patients with limb ischemia also have coronary artery disease. Life table analysis (life table analysisi) showed that the 5-year survival rate of patients with intermittent claudication was 70% and the 10-year survival rate was 50%. The majority of deaths were due to myocardial infarction or sudden death, with a small percentage of deaths directly due to peripheral vascular occlusion. The prognosis is worse in patients with diabetes and smoking, and amputation is required in about 5% of patients.