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Carotid Artery Disease

Four arteries supply blood to the brain. These are the right and left internal carotid arteries and the right and left vertebral arteries. The two internal carotid arteries, found in the neck, supply 85 percent of blood flow to the brain.

Carotid artery disease occurs when the carotid arteries become narrowed or blocked. The major cause of carotid artery disease is atherosclerosis. This is a slow process in which deposits of fat, cholesterol, and calcium build up inside the artery. These deposits are called plaque. Like the inside of a rusty water pipe, the wall of the artery becomes rough, hard, and more narrow.

Atherosclerosis mainly affects the major blood vessels of the body, but it occurs to some extent in all arteries. Decreased blood flow to the brain results when the carotid arteries are narrowed.

Small blood clots may form on the plaque's rough surface. A clot can break loose and travel to the brain. This is called an embolus. An embolus can lodge in a small artery and stop blood flow to that part of the brain. Both a narrow artery and an embolus can result in a stroke. A stroke is also called a cerebrovascular accident (CVA). Stroke is one of the leading causes of death in the United States.

Risk Factors
Risk factors are habits, traits or conditions that may increase a person's chance of developing atherosclerosis.

Risk factors for cardiac and vascular disease that cannot be changed include:

• Family history of stroke
• Age
• Gender (male or post-menopausal female)

Risk factors that can be controlled or modified include:

• Cigarette smoking
• High blood pressure
• High blood cholesterol
• Heart disease
• Diabetes
• Blood clotting disorders

Symptoms
Symptoms of carotid artery disease depend on the part of the brain that is affected. Each part of the brain controls certain parts of the body. For example, when an artery to the eye is blocked or narrowed, vision may be affected. One sign of carotid artery disease is a carotid bruit (a French word meaning "noise"). It can be heard with a stethoscope placed over the carotid artery. As blood travels through a narrowed carotid artery, a "whooshing" sound or bruit may be heard.

Other signs of carotid artery disease may include:

• loss of use of an arm or leg
• difficulty walking
• difficulty speaking or understanding words, spoken or written
• loss of vision in one or both eyes or blurred vision
• loss of memory
• loss of balance

When these warning signs occur for a brief time, it is called a mini-stroke or Transient Ischemic Attack (TIA). Transient means brief, and ischemic means a shortage of blood supply. The symptom is sudden and can occur repeatedly. It may last from a few seconds to many hours, but goes away within 24 hours. If any of these symptoms do not go away within 24 hours, a stroke has occurred. However, a stroke may occur with no warning signs. It is important to seek medical attention immediately if any of these symptoms occur.

People who have a TIA related to carotid artery disease are at higher risk of having a major stroke. The risk of a stroke, after the onset of symptoms, is about 12 percent to 13 percent within the first year, and 30 percent to 35 percent at the end of five years.

Screening for carotid artery disease may reduce complications associated with stroke.

 

Review Date: 01/05