Cerebrovascular Disease and Carotid Artery Surgery

The blood supply to the brain is carried by four arteries; the right and left carotid arteries, and the right and left vertebral arteries. The carotid arteries supply blood to the largest part of the brain and travel next to the jugular vein in the front of the neck. The vertebral arteries supply blood to the back of the brain and travel up next to the spine.

Strokes are caused by blockages in the supply of blood to parts of the brain. The symptoms of the stroke depend on which part of the brain is affected. A small stroke may not be noticed. A large stroke can cause coma or death. The right side of the brain controls the left side of the body, so that a right sided stroke would cause a left sided paralysis, and vice versa.

Strokes involve permanent damage to a portion of the brain. If a small blockage occurs which dissolves before permanent damage occurs, the temporary symptoms (such as weakness of a hand or leg, or difficulty speaking) are called a transient ischemic attack, or TIA (or sometimes a mini-stroke). TIAs are warnings that a permanent stroke is about to occur. The blood clots which cause strokes can come from either the heart or one of the arteries which lead to the brain.

One of the most common causes of strokes is atherosclerotic plaque in the carotid artery, which can produce narrowing of the artery, causing small blood clots or parts of the plaque to break off and travel to the brain. Many people have some plaque in the carotid artery without symptoms. However, in some people with very severe narrowing, or with symptoms of "mini-strokes", it has been found that removing the plaque from the artery can reduce the chance of having a major stroke. Removing the plaque requires an operation called a "carotid endarterectomy."

Carotid endarterectomy is a very serious operation, although it is easy to recover from if all goes well. There is always a risk that the operation itself could cause a stroke; therefore, it should never be done unless the risk from the operation is much less than the risk of just taking medication. The decision about whether to have the operation or not is yours. It should be possible for the surgeon to tell you approximately what the risk of stroke with and without the operation would be, and to tell you what he or she would recommend.

In most cases, an arteriogram will be done before making the decision to do the operation. The arteriogram is an x-ray of the arteries to the brain which gives us a "road-map" and helps us plan the operation. If your symptoms are not serious, the arteriogram may be done as an outpatient. If your symptoms are serious, you may be in the hospital on blood-thinning medication before the arteriogram is done. The x-ray is done by placing a thin catheter into the artery in your groin, and passing it up to the area where the brain arteries start, then injecting dye while taking x-rays. The whole procedure takes about an hour, and is not very uncomfortable.

The operation is usually done under general anesthesia, although it can be done under local anesthesia ("Novocain") if necessary. It takes about two or three hours. It is done through an incision in the neck which runs from the collarbone up to just below the ear. During the operation, your brain activity may be watched using an "EEG" machine (brain waves). The surgeon will clamp the artery above and below the blockage. If necessary, a shunt tube will be used to allow the blood to continue to flow to the brain during this part of the operation. The plaque will then be shelled out of the artery, and the artery will be sewn up. After the operation, there is not usually a lot of pain. Your neck may be fairly stiff, but this should improve quickly. Most people are a little hoarse from having the respirator tube in their windpipe. You will be kept in the ICU or the recovery room overnight, because blood pressure often changes rapidly during this period of time. If everything is fine, most people are ready to leave the hospital two days after the operation.

There are a number of risks of this operation. The major risk is stroke. This usually happens during or shortly after the operation because of blood clots which may form in the artery where it was cleaned out. The risk of stroke is fairly small - usually about 2-3% - but stroke can be devastating if it occurs. Injury to some of the nerves in the neck may also occur, although this usually improves without treatment. These nerve injuries may cause temporary or permanent difficulty swallowing or hoarseness.  Numbness of the skin of the neck or ear is common because those nerves are often cut in making the incision. Like any operation, carotid endarterectomy may be complicated by bleeding or infection in the incision. These complications are unusual, but do happen.

After discharge from the hospital, you will need to see the surgeon once or twice, and then yearly. A followup ultrasound study of the carotid arteries will be done. Usually, it is recommended that you take an aspirin a day, which will reduce your future risk of stroke and heart attack.