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 Carotid Artery Disease
What is carotid artery disease? Carotid artery disease is a term for narrowing of the main arteries in the neck — the carotid arteries, which supply blood to the brain — due to the build-up of plaque, a hard, sticky composite of cholesterol and other fats in the blood. Caused by atherosclerosis, if not repaired this build-up can lead to "mini-strokes" called transient ischemic attacks or to full-fledged strokes with severe consequences. The interruption of blood supply can result from the narrowing itself (called stenosis) or from clots associated with it (called thrombosis). The development of plaque can occur in arteries throughout the body but is most damaging when it happens in key vessels, such as the coronary and carotid arteries. Just as blockage of the coronary arteries can lead to a heart attack, blockage of the carotids can lead to a stroke, or the death of brain cells. More than 150,000 people die from strokes each year in the United States. But even non-fatal strokes (afflicting another 600,0000 Americans annually) can lead to devastating consequences. These can include severe problems with memory, with the ability to speak and comprehend others' speech, and weakness or paralysis that often affects an entire side of the body, including the face, an arm and a leg. Effects can vary depending on which parts of the brain are affected. A transient ischemic attack is a temporary episode in which some of the signs of a stroke may occur for a period of a few minutes to a full day before disappearing. It is important to state that a transient ischemic attack (or TIA) may be a warning sign of an impending stroke and requires immediate medical attention. The good news is that doctors have developed sophisticated techniques for dealing with carotid artery disease, including a surgical procedure called endarterectomy and an endovascular approach called angioplasty and stenting. The physicians of Hartford Specialists have been leaders in the development of these surgical and non-surgical techniques, and work closely together to ensure that patients receive the treatment that is best suited for them. (return to top) What are the symptoms of carotid artery disease? This is somewhat of a trick question because the development of atherosclerosis in your carotid arteries very likely will occur without showing any symptoms whatever until the actual signs appear of a transient ischemic attack or full stroke in progress. It is clear that risk factors for development of carotid artery disease include a family history of stroke among immediate relatives and a personal medical history of hypertension, elevated cholesterol levels, smoking and diabetes. (return to top) What are the symptoms of TIAs and strokes? The symptoms of TIAs and strokes are the same, with the difference that a transient ischemic attack disappears after a period of several minutes to a day. The other difference is that a TIA is more likely to result from a blood clot that has broken loose from an area of stenosis and may be blocking one of the smaller arteries serving a specific area of your brain. It ends because the blood clot spontaneously dissolves. A TIA can occur once or in clusters. If it recurs multiple times, it may involve the same symptoms or different ones. A cluster of TIAs may be a strong signal that a stroke is impending. It's estimated that some 14 percent of people who experience a first TIA or stroke will go on to have another within a year, and that a third will have a stroke within five years. The symptoms of both TIAs and strokes can include any or all of the following:
Again, it should be emphasized that these symptoms — even if experienced as temporary problems that go away in a few minutes — may represent a warning sign that you are at risk for a stroke and require immediate medical attention by a doctor or emergency room. (return to top) What happens in carotid artery disease and stroke? A stroke associated with the narrowing or blockage of a carotid artery is called an embolic or thrombolic stroke, and accounts for about 80 percent of all strokes. About 20 percent of strokes are hemorrhagic, caused by bleeding from leakage or rupture of a blood vessel in the brain that directly damages brain tissue. This article focuses on the carotid artery disease.. With the carotid arteries in the neck serving as the principal channels for blood supply to the brain, atherosclerosis results in the build-up of plaque that causes those blood vessels to narrow or become blocked. Plaque is a sticky substance composed of cholesterol and other fats in the blood that adheres to the arterial walls with a fibrous covering, growing in thickness to create an ever-smaller channel. As the plaque increases, it's likely to do so with a hard, rough surface. It is possible that a severe blockage by itself can reduce blood flow sufficiently to cause brain cells to die, resulting in the effects of a stroke. Associated with a narrowing can be a turbulence in the blood flow that can spur the development of clots. Most strokes are believed to be the result of clots or small bits of plaque that break off and travel to the smaller arteries that directly supply different areas of the brain, depriving them of blood — and precipitating stroke. (return to top) What are the risk factors for stroke? There are some risk factors for susceptibility to stroke that you can't do anything about, such as a family history of stroke or your age (your risk increases as you age, although stoke can occur at any age). Some risk factors can be treated medically, and some can be dealt with through lifestyle changes. Major issues include:
(return to top) How is carotid artery disease screened for and diagnosed? While the signs of atherosclerosis are often silent until a serious event occurs, a physician looking at risk factors such as cholesterol levels and lifestyle issues might be watchful for signs of asymptomatic atherosclerosis. During a physical exam, your doctor may use his or her stethoscope to listen for a rushing sound called a bruit (pronounced bru-ee) in your carotid artery, although its presence or absence is not conclusive. A medical history may define issues such as a family history of stroke, a sedentary lifestyle, and use of tobacco. More likely, if the risk of carotid artery disease is suspected, your doctor may order one or more of several tests, including:
(return to top) How is carotid artery disease treated? The risk of stroke — that is to say the consequences of atherosclerosis in the carotid arteries — can be treated in several ways, including medical therapies, the surgical procedure endarterectomy, and endovascular techniques. The exact approach that's most appropriate depends on a variety of factors, including the extent of the stenosis, past medical history and the patient's general medical condition. The degree of stenosis is usually expressed by doctors as a percentage — meaning that, for example, the artery may be described as 50 percent or 60 percent or 70 percent blocked. Studies have indicated that in terms of rates of subsequent stroke, medical therapy may be most effective for patients with stenosis of less than 80 percent, whereas patients with stenosis 80 percent or greater will do better with endarterectomy or possibly with angioplasty and stentery of the narrowed artery. (return to top) What are the medical therapies for carotid artery disease? Medical therapies often take the form of antiplatelet and anticoagulant drugs that reduce the risk of clots forming. Antiplatelet drugs are substances that make the platelet cells in your blood less likely to stick together. Anticoagulants neutralize clotting factors in the blood. These medical therapies are most likely to be performed as preventive treatments in the instance of a lower degree of stenosis with no symptoms of TIA. They are likely to be utilized as a follow-up treatment for a patient who has had a TIA or a stroke and undergone treatment for it. (return to top) What is thrombolytic therapy? Thrombolysis, or thrombolytic therapy, is an interventional radiology procedure in which a catheter is threaded through your blood vessels to the site of a clot so that a "clot-busting" drug such as TPA (tissue plasminogen activator) can be released with maximum effect to dissolve the clot. The interventional radiologist does this with the help of fluoroscopy, real-time x-rays that allow him or her to visualize the location of the catheter within the arterial system. However, treatment within three hours of the ischemic attack is necessary for the benefits of the thrombolytic agent to outweigh potential complications from the drug's blood-thinning characteristics. For more information on thrombolysis and interventional radiology, click here. (return to top) How is the surgical procedure carotid endarterectomy performed? Fortunately, the area of stenosis in a carotid artery tends to be localized — often less than an inch. Accessing the artery through a small incision in the neck, a shunt is established to temporarily reroute blood flow around the section in question while its repair is undertaken. This is done by opening the arterial segment along its length and removing the plaque inside. The artery then usually has a patch of artificial artery sewn into it to create a wider channel for blood flow. With removal of the shunt, the incisions are closed and blood flow resumed through the renovated vessel. The procedure takes about 2 hours and is usually done asleet. Patients spend four hours in the recovery room for observation and then go to the floor. Most patients go home the morning after surgery. (return to top) How are carotid artery angioplasty and stenting performed? Angioplasty uses a tiny inflatable balloon on the tip of the catheter to physically open up a stenosis. A stent — a tiny metal cylinder — may be placed at the site to keep the area opened. While angioplasty and stenting have many applications throughout the body, in the carotid arteries it may be best suited for individuals who are not good candidates for endarterectomy. (return to top) What are the risks associated with endarterectomy or angioplasty? Any medical procedure carries with it the slight risk of problems such as infection or bleeding or adverse reaction to anesthesia. Procedures involving the carotid arteries involve a small risk that a piece of plaque may become dislodged and flow to the brain, precipitating a stroke during the treatment intended to prevent it. Other small risks may include heart attack — possibly a fatal heart attack — and problems such as injury to nerves that control the vocal cords and other areas. Your doctor can talk with your about the benefits and risks you may experience based on the specifics of your case — the severity of your stenosis, your overall health and other factors. However, studies have demonstrated that, especially in cases of severe stenosis, the benefits from treatment by far outweigh the risks of receiving no treatment and experiencing a stroke — cutting in half patients' risk of having a stroke in the next five years. (return to top) What can I do to prevent carotid artery disease? While endarterectomy is a successful procedure for repairing damaged carotid arteries, preventing carotid artery disease — and atherosclerosis generally — is a far more desirable goal. While family medical history is not something we can control, there are many risk factors we can control through medical assistance and lifestyle changes. These include:
(return to top) For additional information: You can find additional information about stroke, endarterectomy and carotid artery disease at web sites sponsored by government agencies, societies and healthcare institutions. It should perhaps be noted that the World Wide Web is open to many sources posting questionable information and promises, and you are encouraged to seek information from established, reputable organizations. Likely sources include: The National Institutes of Health www.nih.gov The American Heart Association www.americanheart.org The Vascular Disease Foundation www.vdf.org Vascular Web www.vascularweb.org The Society of Interventional Radiology www.sirweb.org Emedicine www.emedicine.com |
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