Carotid artery disease (also called carotid stenosis) refers to the blockage and narrowing of the carotid arteries due to a fatty buildup called plaque. This condition is also referred to as atherosclerosis and the plaque material as an atheroma. The fatty plaque material accumulates in the blood vessels and results in a narrowing (stenosis), which leads to clot formation that can break off and go to the brain, or cause a critical decrease in blood flow.
Aging and abnormally high lipids and cholesterol levels in the body are the main causes of carotid stenosis. Several other factors such as high blood pressure, cigarette smoking, and obesity also increase the risk of developing carotid artery disease.
The most common symptom of carotid artery disease is a TIA (transient ischemic attack) — a temporary cerebrovascular event that does not lead to permanent brain damage. TIAs are referred to as "mini strokes" and result from a temporary brain vessel blockage. Symptoms are often short-lived and can last from seconds to hours. They include:
A person experiencing these symptoms should seek emergency medical help and notify his or her primary care physician immediately; many AVM sufferers have a major stroke within two weeks of such symptoms. Many patients with carotid artery disease do not have symptoms. This is known as asymptomatic carotid disease. Depending on the degree of blockage in the carotid arteries, these patients may still be at a high risk for stroke.
Some people who experience a TIA are often found to have carotid artery disease. Frequently, a primary care physician can detect early warning signs during regular physical exams, by specifically asking about TIA type symptoms. Hearing a carotid bruit, the noise made by the blood flowing past an area of blockage, may indicate narrowing in the carotid system.
The tests that your primary care physician may order will provide information regarding the presence and degree of stenosis. These tests may include: Doppler ultrasound — this is a noninvasive test in which ultrasound waves are used to reconstruct an image of the carotid arteries and the status of blood flow through the artery. MRI/MRA — Magnetic resonance imaging (MRI) and magnetic resonance angiogram (MRA) employ magnetic fields to generate an image of the head and neck. Arteries in the neck and brain can be visualized, and the blockage can often be detected. CTA-Angiography by CT — This helps determine the degree of narrowing and the amount of calcium in the vessel. Angiography — Angiography is performed using X-ray. Pictures are taken while medication is injected directly into the artery. The resulting angiogram is the most accurate way of looking at arteries in the neck, head and brain, and provides information that cannot be obtained with other tests.
Modifying risk factors and living a healthy lifestyle may prevent the development of carotid stenosis and reduce the risk of stroke. The main modifiable risks include:
For patients with less than 50 percent stenosis, drug therapy is often prescribed. Monitoring and treating cholesterol, blood pressure and diabetes is done in conjunction with lifestyle modification, such as weight loss and increasing level of exercise. The two types of drugs most commonly used to treat mild stenosis are:
Patients with more than 50 percent blockage are recommended for surgical therapy. The plaque buildup in the artery can be removed in a surgical procedure called carotid endarterectomy. Several major national and international scientific studies have proven the effectiveness of this procedure in reducing the risk for major stroke. What are the risks of the operation? The main risk of carotid endarterectomy is the development of a stroke. However, this risk is relatively low; it is estimated at 1.5 to 3.0 percent. Much of the risk is related to technical factors, and several different surgical methods have been suggested to improve the already low risk of the procedure. These include the use of vein patches or synthetic patches to enlarge the diameter of arteries during repair. What is done during a carotid endarterectomy? During a carotid endarterectomy, the patient is anesthetized under local or general anesthesia. The surgeon exposes and opens the carotid artery. The atherosclerotic plaque is removed, and the vessel is inspected for any remaining fragments or debris. Here at Lahey, we use an operating microscope, which significantly aids in this process. The artery is then sewn closed using specialized suture material, and the neck incision is closed. The patient is hospitalized for 24 to 48 hours after the procedure, and can return to normal activities in four to six weeks. Are there alternatives to carotid endarterectomy? In certain situations, such as recurrent carotid stenosis, or in patients who are considered high risk for surgery, a different treatment called carotid stenting may be recommended. In this procedure, a small, tube-like stent is threaded up to the narrowed artery from the groin (in the same way the angiography catheter is inserted). The stent is expanded and opens the narrowing. Although this procedure is fairly new, and has not undergone the same rigorous scientific study as carotid endarterectomy, for select patients it may prove to be the best option. Carlos A David, MD, and Zoher Ghogawala, MD, lead our cerebrovascular effort and provides treatment for patients with carotid artery disease.