Carotid artery disease, also known as carotid artery stenosis, is a narrowing of the carotid arteries commonly caused by a build up of plaque (fatty deposits). 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.
Carotid disease is very highly associated with stroke. Approximately 75% of all ischemic strokes occur in the distribution of the carotid arteries in the neck. Commonly, a piece of the plaque that develops in the carotid artery breaks off and travels to the brain causing either TIAs or stroke.
Detecting and Diagnosing Carotid Disease
Carotid disease is usually discovered either because a patient experiences symptoms or because a physician listens over the neck and hears an abnormal sound called a bruit during a routine physical examination. It is important to recognize the symptoms that may herald an oncoming stroke so that medical care can be started as promptly as possible.
The most common method of diagnosing carotid artery disease is duplex ultrasound. Duplex ultrasound is a non-invasive method of imaging the arteries to determine whether there is significant plaque.
Occasionally other studies may be needed, such as an MR angiogram, CT angiogram or a traditional contrast angiogram. When performed by trained ultrasound technicians in an accredited diagnostic vascular ultrasound laboratory such as the one at UCSD, carotid duplex ultrasound is extremely reliable, and in the great majority of cases, is the only study needed for planning surgical treatment.
Treatment of Carotid Disease
Carotid artery disease may be treated by medical therapy, surgery or by a combination depending on the individual patient’s situation.
In recommending treatment for a patient, the physician considers these factors:
- Whether or not the patient has symptoms
- How much narrowing (stenosis) is present according to ultrasound or angiogram tests
Studies show that a surgical procedure called carotid endarterectomy is clearly more effective than medical treatment in patients who meet any of the following conditions:
- The patient is symptomatic and has greater than 70% stenosis
- The patient has no symptoms and has greater than 80% stenosis based on ultrasound or 60% by angiography
- The patient has moderate-grade carotid artery stenosis which is continuing to cause symptoms even with medical management
In patients who have symptoms and greater than 70% stenosis, the results of a large number of prospective randomized trials show that treatment with a combination of carotid endarterectomy and aspirin results in dramatically lower rates of stroke than treatment with aspirin alone. For this reason, surgical treatment is recommended for symptomatic patients who have a greater than 70% stenosis as well as for symptomatic patients who have greater than 50% stenosis and are continuing to have symptoms despite being on medical therapy.
Studies also show that asymptomatic patients benefit from surgical treatment compared to medical treatment if the operation is performed by a surgeon who has a personal record of very low stroke rates, morbidity rates and mortality rates for this operation.
Most patients who have asymptomatic carotid stenosis will not go on to have a stroke. However, more than 50% of patients who go on to have a stroke will have proceeded from being asymptomatic one day to having a stroke the next. The challenge is to identify which patients who have asymptomatic stenosis will develop a stroke and which patients will remain asymptomatic. For this reason, many vascular surgeons believe that surgical therapy should be considered for an asymptomatic patient if the patient is at good risk and the surgeon’s stroke rates and mortality results are acceptable. When discussing treatment options with a patient, each surgeon should inform the patient of his or her own morbidity and mortality rates for the procedures that are being considered.
Carotid Artery Stenting
The treatment of carotid artery disease has evolved over the years and continues to evolve. In recent years, another procedure, carotid stenting, has emerged as a treatment option for carotid disease. Although early results suggest this procedure can be done safely with acceptable and equivalent stroke rates compared to carotid endarterectomy, the results are very operative dependent and we do not have any long-term data on the durability of carotid stenting as compared to carotid endarterectomy. Clinical trials of carotid stenting are ongoing and it appears to be an acceptable alternative for selected high-risk patients who meet certain criteria.
Surgery for the prevention of stroke has a long record of efficacy in selected patients. Identifying those patients who will benefit from surgery for carotid artery disease can go a long way toward reducing the number of people who suffer morbidity or mortality from stroke. Individual patients can help reduce their risk of stroke by controlling hypertension, recognizing the symptoms of carotid artery disease and seeking medical care when symptoms occur.