The definition of arterial occlusive disease of the lower extremities should have a broad and narrow distinction. The broad definition of lower extremity arterial occlusive disease refers to acute or chronic occlusion of lower extremity arteries due to various causes, such as atherosclerosis, arteritis, arterial embolism, arterial trauma, and anatomical structures. Narrowly defined occlusive disease of the lower extremity arteries refers to arterial stenosis or occlusive disease caused by atherosclerotic plaques, and the course of the disease is mostly chronic. There are of course patients who develop an acute exacerbation of the process based on chronic progression. The narrow definition is more widely used, as this condition accounts for approximately 90% or more of all occlusive arterial disease in the broad sense. Early-stage arterial occlusive disease of the lower extremities may not have definite symptoms and may occasionally include slightly low skin temperature in the distal extremities of the lower extremities or cramping after exposure to cold. A more definite early symptom would be impairment of walking function, or what we call intermittent claudication. By intermittent claudication, we mean that when a patient walks for a period of time, discomfort or pain in the lower extremity occurs, which is relieved soon after rest. The symptoms of this claudication may not be pain, but also weakness, soreness, heaviness and other manifestations. Symptoms can appear in the buttocks, thighs, calves and toes, with the calves being the most common. Symptoms appear more quickly when walking quickly or going upstairs. As time passes and the condition worsens, the distance between the onset of symptoms becomes shorter. Overall, only 50% of patients with arterial occlusive disease of the extremities will have symptoms of intermittent claudication. If the degree of lower extremity arterial occlusion worsens further, the patient may develop severe lower extremity ischemia. The blood supply of the lower extremity arteries is no longer sufficient to meet the needs of the limb at rest, resulting in ischemic pain in the lower extremity at rest, or what physicians call resting pain. This pain is characterized by reduced blood flow to the lower extremity due to the relative elevation of the lower extremity when lying down, resulting in more painful symptoms during sleep. If the condition continues to worsen, breakouts and ulcers may develop in the toes or ankles and are very painful. If the ischemic condition does not improve in a timely manner, the ulcer will gradually worsen, gradually changing from dry, grayish white at the beginning to black and eventually developing into necrotic tissue (gangrene).