Carotid artery disease occurs when the carotid arteries, which are the main blood vessels that provide blood to the brain, become narrowed. Blockage in the carotid artery can lead to stroke or death. Carotid artery disease is similar to coronary artery disease, in which blockages occur in the arteries of the heart, and may cause a heart attack.
Atherosclerosis is the most common cause of carotid artery disease. This is due to development of plaques or blockage in the artery. It is characterized by the accumulation of fatty deposits along the innermost layer of the arteries. This progressively thickening of the blood vessel can lead to narrowing of the artery, which can result in a decreased blood flow to the brain resulting in stroke.
Carotid artery disease may be asymptomatic (without symptoms) or symptomatic (with symptoms). Asymptomatic carotid disease is the presence of a significant amount of atherosclerotic build-up without obstructing enough blood flow to cause symptoms. However, a sufficiently tight stenosis will not always cause symptoms. Symptomatic carotid artery disease may result in either a transient ischemic attack (TIA) and/or a stroke (brain attack).
A transient ischemic attack (TIA) is a sudden or a temporary loss of blood flow to an area of the brain, usually lasting a few minutes to one hour. Symptoms usually go away entirely within 24 hours, with complete recovery. Symptoms of a TIA may include, but are not limited to, the following: a. sudden weakness or clumsiness of an arm and/or leg on one side of the body, b. Sudden paralysis (inability to move) of an arm and/or leg on one side of the body, c. loss of coordination or movement, d. numbness or loss of sensation in an arm and/or leg, e. temporary loss of vision or blurred vision, or 3. inability to speak clearly or slurred speech.
Stroke is another indicator of carotid artery disease. The symptoms of a stroke are the same as for a TIA. A stroke is loss of blood flow (ischemia) to the brain that continues long enough to cause permanent brain damage. Brain cells begin to die after just a few minutes without oxygen. The area of dead cells in tissues is called an infarct.
In addition to a complete medical history and physical examination, diagnostic procedures for carotid artery disease may include any, or a combination, of the following:
Carotid artery duplex scan – This is a type of vascular ultrasound study performed to assess the blood flow of the carotid arteries. It is a very useful screening tool to detect carotid artery blockage and does not incur any radiation or contrast administration.
Computed tomography scan (also called a CT scan) – This is a diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce cross-sectional images of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general x-rays.
Carotid angiography – This is an invasive procedure used to assess the degree of blockage or narrowing of the carotid arteries by taking x-ray images while a contrast dye in injected. The contrast dye helps to visualize the shape and flow of blood through the arteries as x-ray images are made.
In persons with narrowing of the carotid artery greater than 69 percent, a more aggressive treatment may be recommended, particularly in persons with symptoms. Surgical treatment decreases the risk for stroke after symptoms such as TIA or minor stroke, especially in persons with an occlusion (blockage) of more than 70 percent who are good candidates for surgery.
Surgical or interventional treatment includes:
Carotid endarterectomy (CEA) – Carotid endarterectomy is a procedure used to remove plaque and clots from the carotid arteries, located in the neck. Endarterectomy may help prevent a stroke from occurring in persons with symptoms with a carotid artery narrowing of 70 percent or more.
Carotid artery angioplasty with stenting (CAS) – Carotid angioplasty with stenting is an option for patients who are high risk for carotid endarterectomy. This is a minimally invasive procedure in which a very small hollow tube, or catheter, is advanced from a blood vessel in the groin to the carotid arteries. Once the catheter is in place, a balloon may be inflated to open the artery and a stent is placed. A stent is a cylinder-like tube made of thin metal-mesh framework used to hold the artery open. Because there is a risk of stroke from bits of plaque breaking off during the procedure, an apparatus, called an embolic protection device, may be used. An embolic protection device is a filter (like a small basket) that is attached on a guidewire to catch any debris that may break off during the procedure.