Your carotid arteries are two large blood vessels in your neck. They supply your brain and head with blood. If you have carotid artery disease, the arteries become narrow or blocked, usually because of atherosclerosis. Atherosclerosis is the buildup of plaque, which is made up of fat, cholesterol, calcium, and other substances found in the blood.
Carotid artery disease is serious because it can block the blood flow to your brain, causing a stroke. Too much plaque in the artery can cause a blockage. You can also have a blockage when a piece of plaque or a blood clot breaks off the wall of an artery. The plaque or clot can travel through the bloodstream and get stuck in one of your brain's smaller arteries.
Carotid artery disease often does not cause symptoms until the blockage or narrowing is severe. One sign may be a bruit (whooshing sound) that your doctor hears when listening to your artery with a stethoscope. Another sign is a transient ischemic attack (TIA), a "mini-stroke." A TIA is like a stroke, but it only lasts a few minutes, and the symptoms usually go away within an hour. Stroke is another sign.
Imaging tests can confirm whether you have carotid artery disease.
Treatments may include
Healthy lifestyle changes
Medicines
Carotid endarterectomy, surgery to remove the plaque
Angioplasty, a procedure to place a balloon and stent into the artery to open it and hold it open
NIH: National Heart, Lung, and Blood Institute