The degree of carotid stenosis is classified as mild, moderate or severe, and a stenosis of 70%-90% is considered severe. Severe stenosis can cause reduced blood supply and poor perfusion to the brain tissue distal to the vessel, resulting in ischemia and damage to the brain tissue. The heavier the stenosis and the thicker the lipid layer, the higher the chance of vascular occlusion. Severe stenosis indicates that the lesion has reached an irreversible stage and requires active treatment and intervention. Stenosis is mostly caused by atherosclerosis, with a thickened lipid layer and unstable fibrous plates, which are prone to the formation of thrombus distal detachment, leading to the occurrence of cerebral infarction and cerebral infarction.