Carotid Endarterectomy

The two carotid arteries, one on each side of the neck, are the main blood supply to the brain. Each carotid artery extends upward from the aortic arch of the heart to either side of the windpipe and then branches off into the external carotid and internal carotid arteries. The internal carotid artery is the more important branch because it continues into the brain. The external carotid artery is one of many arteries that supply blood to the face and scalp.

As people age, plaque made up of cholesterol or lipids, calcium, and fibrous tissue can build up in the walls of their arteries. As the plaques enlarge, the arteries become narrow and stiffened, a process known as atherosclerosis, or hardening of the arteries. When enough plaque has accumulated to interfere with blood flow to the brain, a person is said to have carotid artery disease.

Blood clots can form on plaques and occlude, or block, the carotid artery. Such a blockage interrupts the flow of blood to the brain, causing ischemia, or a lack of oxygen. If blood flow is blocked for even a short period of time, it can cause an ischemic stroke, which can result in brain damage or death.

In patients with moderate to severe blockages of the carotid arteries, a carotid endarterectomy is a safe and long-lasting treatment that has been shown to prevent stroke.

To perform a carotid endarterectomy, the surgeon makes an incision in the neck to access the carotid artery, and applies clamps to temporarily halt blood flow while he or she opens the artery. Often a temporary shunt, or bypass, is used to reroute blood flow around the clamped section of the artery while the lining containing plaque is removed. After the artery has been entirely cleaned and made smooth and open again, it is sewn shut, often with a patch to ensure that the vessel is as wide as a normal artery.

Another procedure, called carotid stenting, is emerging as an alternative treatment to open partially blocked carotid arteries. In carotid stenting, a procedure known as angioplasty expands the carotid artery walls with a tiny balloon so that physicians can insert a stent (wire cage) to keep the passage open.

WHEN IS IT INDICATED?

A physician decides to perform an endarterectomy based on the presence of symptoms and how severely plaque is blocking the patient's carotid artery.

Unfortunately, a stroke may be the first symptom in many patients with severe carotid blockage. Carotid endarterectomy is of proven benefit even in the absence of any symptoms at all if the amount of blockage is very severe. Usually physicians will consider intervention when an artery becomes 60 to 70 percent narrowed regardless of whether the patient has had symptoms.

PRE-TREATMENT GUIDELINES

Before performing a carotid endarterectomy, the surgeon assesses plaque buildup inside the artery. Most commonly, the surgeon uses duplex ultrasound, a safe and painless diagnostic test that uses high-frequency sound waves to make images of body tissues. Duplex ultrasound produces high-quality pictures and can also measure how fast blood flows and show turbulence in the bloodstream.

One of the following tests may also be performed:

Arteriogram, known also as angiogram;
Magnetic resonance angiography; or
CT angiography.

WHO IS ELIGIBLE?

The best candidates for endarterectomy have moderate to severe narrowing of the arteries (50 percent or greater) and have not had a disabling stroke.

Some conditions may exclude patients from the procedure, at least temporarily. These include cancer and uncontrolled hypertension.

RISK FACTORS FOR POSSIBLE COMPLICATIONS

As with any surgery, the outcome of endarterectomy depends on many different factors, including a person's state of health. Although carotid endarterectomy is not a major operation in terms of surgical stress or recovery, it is a major operation in terms of the importance of the blood vessel being treated. The best way to evaluate the risk of complications is to compare the chances of having a stroke because of the operation with the chances of having a stroke if the carotid plaque is not removed and the physician treats the patient's atherosclerosis with medications.

WHAT TO EXPECT

Basic principles of endarterectomy involve making an incision, opening the blocked artery, and removing the built-up plaque. Endarterectomy can be performed with the patient asleep under general anesthesia, or with the patient awake and the neck area numbed with a local anesthetic. Some surgeons prefer using local anesthesia so that the patient can talk to the physician during the procedure, helping monitor the brain's reaction to the decreased blood supply. Other surgeons prefer general anesthesia, with systems for monitoring blood pressure, temperature, and sometimes even brain function.

The surgeon makes an incision along one side of the neck and carries the incision down to expose the blocked carotid artery. The sections of the carotid arteries affected by plaque buildup are separated from surrounding tissue and are clamped to temporarily stop blood from flowing through them.

Once the arteries are clamped, the surgeon makes an incision directly into the section of the carotid artery that is blocked by plaque. During the time it is open, blood does not flow through the artery. The surgeon removes or peels out the entire plaque deposit by removing the inner lining of the diseased section of artery.

Carotid endarterectomy has a promising outcome for patients with moderate to severe atherosclerosis. The procedure reduces risk of stroke much more effectively than medication alone. The most important outcome of the procedure is the highly significant reduction in stroke risk thereafter.

POST-PROCEDURE GUIDELINES AND CARE

Following surgery, most carotid endarterectomy patients are kept for observation in a regular hospital room and must elevate their head and have it immobilized for at least 24 hours afterward. During this recovery time, patients receive intravenous fluids for hydration and nutrition, and the physician carefully monitors brain function and blood pressure and checks for abnormal bleeding.

POSSIBLE COMPLICATIONS

Surgery in general poses risks. Some patients react to anesthesia medicines or have problems breathing. Excessive bleeding and infections can occur because of surgery. Complications specific to endarterectomy include stroke; restenosis, or re-blockage of the carotid artery; temporary nerve injury; and scarring.

LIFESTYLE ADJUSTMENT

Endarterectomy may reduce risk of stroke, but it does not address the cause of hardening of the arteries. Patients should address risk factors for atherosclerosis by eating more foods low in saturated fat, cholesterol, and calories; exercising; losing weight; and quitting smoking.

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