The carotid arteries are blood vessels in the neck that bring blood to the brain. Carotid artery stenosis (CAS) is a condition caused by cholesterol buildup in the carotid arteries that prevents normal blood flow to the brain. This condition can cause transient ischemic attack or stroke. Transient ischemic attack, sometimes called a “mini-stroke,” is caused by a temporary blockage of blood flow to the brain and does not cause serious long-term brain damage. In stroke, blockage lasts long enough that some brain tissue dies. Although CAS is a risk factor for stroke, only a small proportion of strokes without symptoms are related to it.