WHAT IS CAROTID ARTERY STENOSIS?
The term refers to the narrowing of the carotid arteries. This narrowing is usually caused by the buildup of fatty substances and cholesterol deposits, called plaque. Carotid artery occlusion refers to complete blockage of the artery. When the carotid arteries are obstructed, you are at an increased risk for a stroke, the third leading cause of death in the U.S.
Like the arteries that supply blood to the heart (the coronary arteries), the carotid arteries can also develop atherosclerosis or “hardening of the arteries” on the inside of the vessels. Over time, the buildup of fatty substances and cholesterol narrows the carotid arteries. This decreases blood flow to the brain and increases the risk of a stroke.
A stroke is similar to a heart attack. It occurs when blood flow is cut off from part of the brain. If the lack of blood flow lasts for more than three to six hours, the damage is usually permanent. A stroke can occur if:
The artery becomes extremely narrowed
There’s a rupture in an artery to the brain that has atherosclerosis
A piece of plaque breaks off and travels to the smaller arteries of the brain
A blood clot forms and obstructs a blood vessel
Strokes can occur as a result of other conditions besides carotid artery disease. For example, sudden bleeding in the brain, called intracerebral hemorrhage, can cause a stroke. Other possible causes include:
Sudden bleeding in the spinal fluid space -- subarachnoid hemorrhage
High blood pressure
Blockage of tiny arteries inside the brain
The risk factors for carotid artery disease are similar to those for other types of heart disease. They include:
Hypertension (high blood pressure) -- the most important treatable risk factor for stroke
Abnormal lipids or high cholesterol
Family history of atherosclerosis, either coronary artery disease or carotid artery disease
How is carotid artery stenosis evaluated?
Carotid artery stenosis sometimes causes an abnormal sound, or bruit, in the artery that can be heard with a stethoscope. Imaging tests to diagnose, localize and measure stenosis include:
Carotid ultrasound (including Doppler ultrasound): This test uses sound waves to create real-time pictures of the arteries and locate blockages. Doppler is a special ultrasound technique that can detect areas of restricted blood flow in the artery.
Computed tomography angiography (CTA): CTA uses a CT scanner to produce detailed views of the arteries anywhere in the body – in this case, in the neck. The test is particularly useful for patients with pacemakers or stents.
Magnetic resonance angiography (MRA): This noninvasive test gives information similar to that of CTA without using ionizing radiation.
Cerebral angiography: Also known as intra-arterial digital subtraction angiography (IADSA), cerebral angiography is a minimally invasive test in which a catheter is guided through an artery to the area of interest. Contrast material is injected through the tube and images are captured with x-rays.
The goal of treatment is to reduce the risk of stroke (cerebrovascular accident). The National Institute for Clinical Excellence (NICE) and other guidelines also recommend that patients with symptomatic carotid stenosis be given carotid endarterectomy urgently, since the greatest risk of stroke is within days. Carotid endarterectomy reduces the risk of stroke or death from carotid emboli by about half.