The brain is a special oxygen-demanding organ, with about 750-1000 ml of blood per minute supplying the brain. Each side of the internal carotid artery passes about 350 ml of blood per minute. When the internal carotid artery stenosis exceeds 50%, the blood supply to the brain will be severely affected. Current studies have found that nearly 1/3 of strokes are related to carotid stenosis. Available studies suggest that carotid stenosis can lead to stroke in three ways: First, by reducing blood flow. Due to the presence of atherosclerotic plaque, the lumen of the carotid artery is severely narrowed causing the brain to not receive adequate blood supply. Second, atherosclerotic plaque ruptures. Fragments of ruptured plaque can block the blood vessels in the brain, leading to occlusion of the lumen of the cerebral vessels and the occurrence of stroke. Third, thrombosis. The rupture of atheromatous plaque in the carotid artery causes the inner surface of the artery to become unsmooth, and the body responds by repairing the damage. Platelets may gather locally, and a thrombus may form in the carotid artery or cerebral vessels, slowing down the blood flow or completely occluding it, leading to stroke.