Paul E. Collier, M.D., F.A.C.S.
Board Certified in General and Vascular Surgery
International Society of Cardiovascular Surgery
Society of Clinical Vascular Surgery
Fellow of the American College of Surgery
Editorial Reviewer, Journal of Vascular Surgery
Board Consultant, American Board of Surgery
Eastern Vascular Society
Allegheny Vascular Society, Past President
Medical Director, Non-Invasive Vascular Lab, Sewickley Valley Hospital
Sewickley Valley Hospital Office
Sewickley Valley Hospital - 4th Floor
701 Broad Street
Sewickley, PA 15143
412 749-9812 (fax)
Carotid Artery Disease
Advances in Surgical Therapy
Arteries are the blood vessels that deliver oxygen-rich blood throughout your body. The carotid arteries are located in your neck - one on each side. They have an important job: they are the fuel pipes to your brain. But, like pipes in an old house, sometimes these arteries can become clogged as a result of the buildup of fatty deposits. This is commonly known as "hardening of the arteries," or more accurately, atherosclerosis. The fatty deposit is called plaque; the narrowing of the artery is called stenosis. The degree of stenosis is usually expressed as a percentage of the normal diameter of the opening. If this blockage becomes severe, the flow of blood to that part of the brain stops and that part of the brain dies. This called a stroke, or "brain attack".
Strokes are common. Many people do not know that stroke ranks as the third leading killer in the United States after heart disease and cancer with about 730,000 new cases each year. On average, someone suffers a stroke every 53 seconds; someone dies of one every 3.3 minutes. As many as 3 million Americans have survived a stroke with more than 2 million of them sustaining some permanent disability. The overall cost of stroke to the nation is $30 billion a year. The emotional and personal toll is immeasurable. Since the late 1950s carotid artery disease has become recognized as the major preventable cause of stroke in the United States and is responsible for about 75 percent of the nearly 150,000 U.S. stroke deaths each year.
Improvements in diagnostic technology have made it much easier and safer for physicians to detect this often silent danger lurking in patient's necks. The operation to clean out the artery has advanced with time. It is now clear that in the hands of well trained, experienced vascular surgeons, the stroke prevention benefits of operation far outweigh the risks. Numerous studies have shown that the best results are achieved by surgeons with the most experience.
Who Is At Risk?
Carotid artery problems become more common as people age. Overall, the prevalence of high-grade carotid stenosis ranges from 5% to 10% in persons over the age of 65 years. Certain medical conditions can increase your chances of arteriosclerosis and carotid artery blockage. These risk factors would include smoking, high cholesterol, high blood pressure, diabetes, coronary artery disease, obesity and family history of stroke.
If a significant blockage can be found before it becomes too severe, treatment is available to help prevent a stroke. But, the symptoms that patients experience from carotid artery blockage can range from none to a stroke.
- Some patients have no symptoms and the presence of a severe blockage in the neck is only suggested when their doctors hear a noise over the artery in the middle of their neck. Called a bruit (pronounced brew-ee), this noise is the sound blood makes when it rushes through partially blocked arteries. By listening with the stethoscope, a doctor can often tell which arteries are affected.
- Some patients have a mini stroke or TIA (transient ischemic attack) warning them of the risk of an impending stroke. These symptoms include temporary loss or partial loss of vision in one eye, slurring or jumbling of speech, sudden dizziness or loss of balance, or temporary loss of feeling or movement in an arm or leg or one side of the face.
- Unfortunately, some patients' first symptom can still be a stroke. These strokes range in severity from mild to incapacitating.
To confirm the diagnosis of a carotid artery problem, your doctor will take a complete medical history, conduct a physical examination, and perform a number of special tests. Your doctor will ask about your medical history and any symptoms you may have such as lightheadedness, speech or vision problems, numbness, or muscular weakness. As a part of your physical exam, your doctor will take your pulse and blood pressure and check for a bruit.
The diagnosis of carotid artery blockage used to depend upon the performance of an arteriogram (also called an angiogram) where x-ray dye is injected into the blood stream to visualize the carotid arteries. Much like a cardiac catheterization, this test is uncomfortable for patients, expensive and has some risk. These risks include stroke, kidney failure and allergic reactions to the iodine x-ray dye. Improvements in technology have now made it possible to detect and quantify carotid artery blockage with a high degree of accuracy without the need for an arteriogram. In place of an arteriogram, your doctor may ask you to have a non-invasive ultrasound Duplex study to evaluate blood flow in your carotid artery. This test uses sound waves bounced off red blood cells to create an image which shows the size and shape of the carotid arteries, as well as how much blood is flowing through them.
Studies at Sewickley Valley Hospital (Collier, Journal of Cardiovascular Surgery, 1998) and other major institutions have demonstrated that many patients (93% at SVH) do not require an arteriogram any more. The decision whether or not to operate and how best to perform the operation can be safely made without performing an arteriogram in the majority of patients.
If you have hardening of the arteries in your neck, chances are that other arteries in your body are also affected. The presence of a carotid bruit is often a sign of significant coronary artery disease. Studies have shown that carotid plaques, as found on ultrasound examination, were significantly more common in both men and women whose parents died prematurely of CHD than in subjects with no familial history of premature death from CHD. All patients being evaluated for carotid disease should undergo an evaluation for heart disease, including EKG, stress tests, and/or echocardiography, as indicated.
Who Should Be Evaluated for Carotid Disease?
All adults should be aware of the problems and discuss risk factors and risk reduction with their doctor. Certain individuals should be formally screened for significant carotid disease. This would include symptomatic patients who have had mini-strokes. Individuals with no symptoms should also be screened if they have a bruit, severe coronary artery disease (possibly, before bypass surgery), or severe peripheral vascular disease of the legs.
Once a carotid artery blockage is diagnosed, three treatment options are available. The choices are basically do nothing, medical treatment, or consider surgery. Which treatment is best depends upon three factors:
1) the presence or absence of symptoms
Medical treatment is prescribed for those with non-critical stenosis or those too ill for surgery. Medical therapy does not reduce a blockage once it has developed, but may help prevent a stroke. Control of risk factors are the mainstay of medical management: weight reduction, stopping smoking, control of high blood pressure and heart disease, reducing high cholesterol, and tight control of diabetes. Additionally, physicians may prescribe aspirin, Coumadin, Ticlid, or Plavix. These drugs reduce the clotting of the blood which helps prevent small blood clots from getting stuck in a partially blocked artery.
2) the amount of blockage
3) the patient's overall medical condition.
Patients who have had transient warning symptoms or a mild to moderate stroke and have a blockage between 70% and 99% should undergo a carotid endarterectomy (have the artery cleaned out) if their overall medical condition is satisfactory. This is because the risk of stroke is so high when patients only take medicine for prevention of stroke. All of the modern, comparative studies overwhelmingly proved this. Recent studies have suggested that some relatively young, healthy patients with blockages between 50% and 69% also benefit from carotid endarterectomy, but this is unusual. Symptomatic patients with blockages less than 50% and the majority of those patients with blockages less than 70% should simply take one aspirin/day and be followed very closely by their doctor.
The treatment of patients with asymptomatic carotid artery blockages is somewhat controversial. The ACAS (Asymptomatic Carotid Artery Study) demonstrated a 55% reduction in stroke risk in men who underwent operation. Many vascular surgeons believe that operation should only be performed in relatively healthy asymptomatic patients with carotid artery blockages between 80% and 99%. There is no role for operation on patients with total (100%) blockages of their carotid artery.
Carotid Artery Surgery
The operation to remove the blockage is called a carotid endarterectomy. This procedure has over a 40-year track record. It was first described in the mid-1950s. It began to be used increasingly as a stroke prevention measure in the 1960s and 1970s. Recent controlled studies have demonstrated it's usefulness in stroke prevention.
Carotid endarterectomy is performed through a three inch incision on the side of the neck. The artery is fairly superficial lying just deep to the muscles. For this reason the operation can be performed using either general anesthesia (patient asleep) or local anesthesia (patient awake). Although, many patients react negatively to the thought of having their neck operated upon while they are awake, we have shown at Sewickley Valley Hospital (Collier, Seminars in Vascular Surgery, 1998) that this is actually well tolerated by patients and is safer for them.
The operation itself takes between one and three hours to perform, depending on the skill of the surgeon. Basically, once the artery is exposed, the inner two layers of the artery (where the disease is) are scraped out. The artery and neck are then closed. The operation is simple in concept, although it is technically demanding and must be performed flawlessly.
The care of patients postoperatively is highly variable. Seven years ago, all patients went to the Intensive Care Unit for at least a day and stayed in the hospital from five to seven days. Revolutionary work at Sewickley Valley Hospital (Collier, Journal of Vascular Surgery, 1992) showed that only 5% of patients required the ICU postoperatively. Not going to the ICU is much more comfortable for patients and their families, is safe, and saves Medicare a vast amount of money annually.
We have also demonstrated that most of the risk of the operation has resolved within three to four hours postoperatively (Collier, Vascular Surg., 1997). We have shown that it is safe for patients to leave the hospital after one day and return to their normal activities quickly (Collier, American Journal of Surgery, 1995). The only real restriction is that patients are not allowed to drive a car for one week. Otherwise, they can resume normal, reasonable activity without fear.
Results of Surgery
The results of carotid artery surgery are critically dependent upon the training and skill of the surgeon and the reason for operation. Good results also depend upon the number of carotid operations that the surgeon performs. Asymptomatic patients should have a risk of stroke from operation of 1% to 3%. Symptomatic patients should have a risk of 2% to 5%. The surgeon should be able to tell you what his results are, not quote what the expected results should be. At Sewickley Valley Hospital the stroke risk has been between 1% and 2% over the last 9 years. (Collier, Journal of Vascular Surgery, 1997).
Modern balloon and stent technology is beginning to be applied to the treatment of carotid artery blockages. At present, the best centers in the country are reporting stroke and death risks that are four times higher than operation upon the carotid artery. If a patient is interested in undergoing a carotid artery stent procedure, he or she should make sure that the procedure is performed at a center that is participating in a trial approved by the U. S. Food and Drug Administration.
The carotid arteries are the main fuel lines to the brain. A blockage can cause no symptoms, a mini-stroke, or a full brain attack. Without treatment, one-third of all people who have had a mini-stroke go on to have a full stroke. But when carotid artery problems are diagnosed early, stroke can often be prevented through surgery, medication, and simple changes in lifestyle. To reduce the chance of carotid artery problems, reduce your risk factors. If surgery is needed, selecting a surgeon with specialty training in vascular surgery or significant experience, particularly with carotid endarterectomy, is crucial. Because atherosclerosis is an ongoing process, new blockages may develop in either carotid artery over time. Your doctor may want to see you on a regular basis to check for the early warning signs of carotid artery problems.
For more Information
National Institute of Neurological Disorders and Strokes
P.O. Box 5801
Bethesda, MD 20824
National Stroke Association
96 Inverness Drive East, Suite I
Englewood, CO 80112
New Guidelines on Stroke Prevention
The Journal of the American Medical Association