Carotid Endarterectomy and Stenosis
Carotid endarterectomy is a common vascular surgical procedure which may help prevent the risk of having a stroke. Scientific evidence from recent studies supports carotid endarterectomy as an effective method of stroke prevention for people with carotid artery blockage of 70 percent or greater. It also may be beneficial for people with moderate blockage of 50 to 69 percent and recent symptoms of stroke.
The carotid arteries are the main blood vessels to the brain. Carotid arteries are located on each side of the neck and extend from the aorta in the chest to the base of the skull. These arteries supply oxygen-rich blood to the brain. Plaque forms when the internal carotid arteries become blocked by fat and cholesterol build-up. This process is called atherosclerosis. Blockage of the internal carotid arteries can reduce blood supply to the brain and may lead to a stroke.
The plaque may cause the blood to flow abnormally, which may lead to blood clots. A clot may remain at the site of narrowing and prevent blood flow to all of the smaller arteries it supplies. Alternatively, a clot can travel and wedge into smaller vessels. This is called an embolism. If a clot or plaque blocks the blood flow to the brain, it can lead to an ischemic stroke, which may cause brain damage or death. If a clot or plaque blocks a tiny artery in the brain, it may cause a transient ischemic attack (TIA), also known as a mini-stroke.
Severe blockage is called carotid stenosis. Carotid stenosis may cause the patient to experience a TIA. Common temporary symptoms include difficulty speaking or understanding others, loss or blurring of vision in one eye and loss of strength or numbness in an arm or leg. Usually these symptoms resolve in less than 10 to 20 minutes and almost always within one hour. Even if all the symptoms resolve, it is very important that anyone experiencing these symptoms call 911 and immediately be evaluated by a qualified doctor.
Carotid stenosis is frequently asymptomatic. A doctor may detect it through an abnormal sound called a bruit (BROO'e) when listening to the carotid arteries with a stethoscope.
Prior to determining if a patient is a candidate for a carotid endarterectomy, the doctor will give him or her a thorough examination, including taking a medical history. Individuals with the following medical conditions are at higher risk of having complications from this surgery:
- Past strokes, especially large strokes without recovery
- A heart attack within the last six months
- Congestive heart failure
- Uncontrolled high blood pressure
- Unstable angina (chest pains)
- The presence of a serious disease, such as severe heart or lung disease
- Widespread cancer with less than a two-year life expectancy
- Plaque that cannot be reached through surgery
- Severe blockage in other blood vessels that supply blood to the brain, such as the carotid artery on the other side
- New blockage in a previous carotid endarterectomy on the same side
- Alzheimer’s or other progressive brain disorders
The doctor may order tests to help diagnose the extent of blockage. These tests include:
The arteries are not normally seen in an x-ray, so contrast dye is utilized. The patient is given a local anesthetic, the artery is punctured, usually in the leg, and a needle is inserted into the artery. A catheter (a long, narrow, flexible tube) is inserted through the needle and into the artery. It is then threaded through the main vessels of the abdomen and chest until it is properly placed in the arteries of the neck. This procedure is monitored by a fluoroscope (a special x-ray that projects the images on a TV monitor). The contrast dye is then injected into the neck area through the catheter, and x-ray pictures are taken. The patient's pulse, blood pressure and breathing are monitored during this procedure. Risks of this procedure include:
- An allergic reaction to the contrast dye
- Although rare, the catheter may damage the artery or knock loose a piece of the artery wall, which can block blood flow and cause a stroke
- A clot or bleeding at the puncture site may result in a partial blockage of blood flow to the leg
In this procedure, ultrasound is used to help detect plaque, blood clots or other problems with blood flow in the carotid arteries. Ultrasonography is very reliable in identifying stenosis but does not accurately assess the degree of stenosis. Because treatment is based on the degree of stenosis, treatment decisions cannot be made from ultrasonography alone.
A water-soluble gel is placed on your skin where the transducer (a handheld device that directs the high-frequency sound waves to the arteries being tested) is to be placed. The gel helps transmit the sound to the skin surface. The ultrasound is turned on and images of the carotid arteries and pulse wave forms are obtained. There are no known risks and this test is noninvasive and painless.
Additional tests may include:
This is a noninvasive study which is conducted in a Magnetic Resonance Imager (MRI). The magnetic images are assembled by a computer to provide an image of the arteries in the head and neck. No contrast material is needed, but some patients may experience claustrophobia in the imager.
This is a diagnostic test that produces three-dimensional images of the head using powerful magnets and computer technology.
The patient will be given either a general or local anesthetic before surgery. In this procedure, the neurosurgeon makes an incision in the carotid artery and removes the plaque using a dissecting tool. Removing the plaque is accomplished by widening the passageway, which helps to restore normal blood flow. The artery will be repaired with sutures or a graft. The entire procedure usually takes about two hours. The patient may experience pain near the incision in the neck and some difficulty swallowing during the first few days after surgery. Most patients are able to go home after one or two days, and return to work, usually within a month. Avoid driving and limit physical activities for a few weeks after surgery.
There are potential complications with carotid endarterectomy surgery, just as there are with any type of surgery. There is a one to three percent risk of stroke following surgery. Another fairly rare complication is the re-blockage of the carotid artery, called restenosis. This may occur later, especially in cigarette smokers. Numbness in the face or tongue caused by temporary nerve damage is a possibility, but uncommon. This usually clears up in less than one month and most often does not require any treatment.
An alternative, new form of treatment, carotid angioplasty and stenting, shows some promise in patients who may be at too high risk to undergo surgery. Carotid stenting is a procedure in which a tiny, slender metal-mesh tube is fitted inside your carotid artery to increase the flow of blood blocked by plaques. The stent is inserted following a procedure called angioplasty, in which the doctor guides a balloon-tipped catheter into the blocked artery. The balloon is inflated and pressed against the plaque, flattening it and re-opening the artery. The stent acts as scaffolding to prevent the artery from collapsing or from closing up again after the procedure is completed.
The patient is awake during this procedure and usually discharged from the hospital the following day. Most patients are able to resume normal activities when they get home.
There are several potential complications of endovascular treatment. The most serious risk from carotid stenting is an embolism, caused by a disrupted plaque particle breaking free from the site. This can block an artery in the brain, causing a stroke. These risks are minimized using small filters called embolic protection devices in conjunction with angioplasty and stenting. There is also a slight risk of stroke due to a loose piece of plaque or a blood clot blocking an artery during or right after surgery.
Hyperperfusion, or the sudden increased blood flow through a previously blocked carotid artery and into the arteries of the brain, can cause a hemorrhagic stroke. Other complications include restenosis and short periods of medically treatable reduced blood pressure and heart rate.
Although surgery may reduce the risk of stroke, it does not stop plaque from building up. To prevent arteries from hardening again, the following health tips may help:
- Eat foods low in saturated fat, cholesterol, and calories
- Exercise regularly, especially cardio exercises such as walking
- Maintain an ideal body weight
- Avoid smoking and
- Discuss taking cholesterol-reducing medications with a doctor
Before undertaking any exercise program, first check with a doctor.
The AANS does not endorse any treatments, procedures, products or physicians referenced in these patient fact sheets. This information is provided as an educational service and is not intended to serve as medical advice. Anyone seeking specific neurosurgical advice or assistance should consult his or her neurosurgeon, or locate one in your area through the AANS’ Find a Board-certified Neurosurgeon”online tool.