What causes carotid artery stenosis?

Atherosclerosis. Usually it is the result of the build up of atherosclerotic plaques over time due to the buildup of cholesterol.
Carotid Stenosis. Usually caused by atherosclerosis (also known as hardening of the arteries) in which palque builds up within the artery walls. Risk is increased by smoking cigarrettes, high cholesterol or lipids, or family history / genetic predisposition. Dissection (tear inside the artery) or fibromuscular dysplasia are other potential causes of stenosis. Ultrasound is usually initial study to evaluate.
Vascular disease. The risk factors are smoking high blood pressure, diabetes, elevated cholesterol, elevated triglycerides, elevated uric acid levels, family inheritance.
Narrowing. Narrowing of the internal carotid artery as determined by ultrasound, mra, cta, or angiogram.