Carotid Artery Disease
What is carotid artery disease?
Carotid artery disease, also called carotid artery stenosis, occurs when the carotid arteries, the main blood vessels that carry oxygenated blood to the brain, become narrowed. The narrowing of the carotid arteries is most commonly related to atherosclerosis (a build-up of plaque, which is a deposit of fatty substances, cholesterol, cellular waste products, calcium, and fibrin in the inner lining of an artery). Atherosclerosis, or "hardening of the arteries," is a vascular disease (disease of the arteries and veins). Carotid artery disease is similar to coronary artery disease, in which blockages occur in the arteries of the heart, and may cause a heart attack.
To better understand how carotid artery disease affects the brain, a basic review of the anatomy of the circulation system of the brain follows.
What are the carotid arteries?
The main supply of blood to the brain is carried by the carotid arteries. The carotid arteries branch off from the aorta (the largest artery in the body) a short distance from the heart, and extend upward through the neck carrying oxygen-rich blood to the brain.
There are four carotid arteries: the right and left internal carotid arteries and the right and left external carotid arteries. One pair (external and internal) is located on each side of the neck. Just as a pulse can be felt in the wrists, a pulse can also be felt on either side of the neck over the carotid arteries.
Why are the carotid arteries important?
Because the carotid arteries deliver blood to the brain, carotid artery disease can have serious implications by reducing the flow of oxygen to the brain. The brain needs a constant supply of oxygen in order to function. Even a brief interruption in blood supply can cause problems. Brain cells begin to die after just a few minutes without blood or oxygen. If the narrowing of the carotid arteries becomes severe enough to block blood flow, or a piece of atherosclerotic plaque breaks off and obstructs blood flow to the brain, a stroke may occur.
