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Carotid Artery Disease

What is Carotid Artery Disease?

Carotid (ka-ROT-id) artery disease is a condition in which a fatty material called plaque builds up inside the carotid arteries. You have two common carotid arteries—one on each side of your neck—that divide into internal and external carotid arteries.The internal carotid arteries supply oxygen-rich blood to your brain. The external carotid arteries supply oxygen-rich blood to your face, scalp, and neck.

Carotid artery disease can be very serious because it can cause a stroke, or “brain attack.” A stroke occurs when blood flow to your brain is cut off. If blood flow is cut off for more than a few minutes, the cells in your brain start to die. This impairs the parts of the body that the brain cells control. A stroke can cause lasting brain damage, long-term disability, paralysis (an inability to move), or death.


When plaque builds up in arteries, the condition is called atherosclerosis (ATH-er-o-skler-O-sis). Over time, plaque hardens and narrows the arteries. This limits the flow of oxygen-rich blood to your organs and other parts of your body.Atherosclerosis can affect any artery in the body. For example, when plaque builds up in the coronary (heart) arteries, a heart attack can occur. When plaque builds up in the carotid arteries, a stroke can occur.

A stroke also can occur if blood clots form in the carotid arteries. This can happen if, over time, the plaque in an artery cracks or ruptures. Blood cells called platelets (PLATE-lets) stick to the site of the injury and may clump together to form blood clots. Blood clots can partly or fully block a carotid artery.

Also, a piece of plaque or a blood clot can break away from the wall of the carotid artery. It can travel through the bloodstream and get stuck in one of the brain’s smaller arteries. This can block blood flow in the artery and cause a stroke. Carotid artery disease may not cause signs or symptoms until the carotid arteries are severely narrowed or blocked. For some people, a stroke is the first sign of the disease.


Carotid artery disease causes more than half of the strokes that occur in the United States. Other conditions, such as certain heart problems and bleeding in brain, also can cause strokes.

Lifestyle changes, medicines, and/or medical procedures can help prevent or treat carotid artery disease and may reduce the risk for stroke.

If you think you’re having a stroke, you need urgent treatment. Call 9–1–1 right away if you have symptoms of a stroke (don’t drive yourself to the hospital). Getting care within one hour of having symptoms is important. You have the best chance for full recovery if treatment to open a blocked artery is given within six hours of symptom onset. Ideally, treatment should be given within three hours of symptom onset.

This educational content is adapted from materials created by the National Heart, Blood and Lung Institute, part of the National Institutes of Health.