Carotid occlusive disease, also called carotid artery stenosis, carotid blockage, or carotid occlusion, is a condition in which one or both of the carotid arteries becomes narrowed or blocked. It is a serious condition that increases the risk of stroke if left untreated.
The carotid arteries are located on either side of the neck — you can feel your pulse quite strongly there by pressing your fingers against your neck below your jaw, to the side of your voice box. Just above the pulse point, the carotid artery branches into two smaller vessels, called the internal and external carotid arteries. Healthy, unobstructed carotid arteries are the critical pathways that supply freshly oxygenated blood from the heart to the brain. When those arteries become narrowed or blocked by plaque, not enough oxygen gets to the brain. The plaque may also break off into small pieces (emboli) that can travel into smaller vessels in the brain and lead to stroke. The area where the main carotid artery branches is a common location for a blockage.
If a carotid artery becomes completely blocked (which is called carotid occlusion, or a carotid blockage) or if piece of the blockage breaks off and travels to a smaller vessel where it completely blocks blood flow, a part of the brain may be completely deprived of oxygen, leading to the destruction of brain tissue. This is what happens during the event we call a stroke, or a “brain attack.” There are nearly half a million strokes each year in the United States, and it’s the third leading cause of death. Stroke claims 140,000 American lives a year — and half of those fatal strokes can be traced to carotid occlusion.
A partial blockage, where one of both carotid arteries becomes narrowed, is called carotid stenosis. The carotid arteries are large enough to allow good short-term blood supply even when they start to narrow, and other arteries sometimes expand to compensate for the reduced flow, but carotid stenosis can still cause a stroke or a transient ischemic attack (TIA). The larger danger of carotid stenosis is that a piece of the atherosclerotic plaque will break off and completely block an artery in the brain, which can also result in a stroke or TIA. A TIA, sometimes called a “mini-stroke,” can cause temporary neurological deficits and is an indicator of an increased risk of a future stroke. A mini-stroke is often small enough to be overlooked or dismissed, but it’s a warning sign that should not be ignored. (See Symptoms of Carotid Occlusive Disease.)
What Causes Carotid Occlusive Disease?
The usual culprit in the narrowing of the carotid arteries is the buildup of atherosclerotic plaque, which is made up of fatty material and blood platelets, along the walls of the blood vessel. That buildup can damage the artery walls, which then narrow and harden. A piece of the fatty deposit may also break off and travel to a smaller artery in the brain, causing a blockage (the breakaway blockage is called an embolus). Contributing factors for plaque buildup include high cholesterol, high blood pressure, diabetes, smoking, and obesity. Carotid occlusive disease also has a family component, so having a family history of stroke increases your own risk.
Watch our webinar on carotid blockage below:
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Reviewed by Philip E. Stieg, PhD, MD
Last Reviewed/Updated: July 2023
Illustration by Thom Graves, CMI