Patients with severe stenosis of the large or middle cerebral arteries may have a survival period of about 10 years. If the degree of stenosis of the cerebral arteries is mild or not in the main arteries, it has no effect on the survival period. If the stenosis is in the large artery or middle artery of the brain, the severe stenosis will lead to insufficient blood supply to the brain tissue, and if it is occluded, it will easily form a large cerebral infarction, which will endanger life or lead to paralysis or bedridden state, and the quality of life will be seriously affected. In the case of small arterial stenosis, even if a cerebral infarction occurs, the infarcted area is not large and generally not life-threatening, and there will be the establishment of collateral circulation when chronic occlusion occurs, which is a certain supplement to the cerebral blood supply and does not lead to a sudden interruption of blood flow resulting in a large cerebral infarction.