Bruce Perler, M.D., Director, Division of Vascular Surgery at Johns Hopkins discusses risks and benefits of carotid endarterectomy versus carotid stenting.
Carotid artery stenosis is marked by the buildup of fatty deposits in two large arteries, the carotids, that run up either side of the neck and carry blood to the brain. A significant blockage in the carotid arteries could eventually choke off the brain’s blood supply and trigger a stroke. You may have been diagnosed with this condition because you have experienced warning signs of a stroke or because your doctor heard a carotid bruit, an abnormal sound that signals fatty buildup in the artery, during a physical examination.
If your carotid arteries are narrowed by more than 50% and you have been experiencing stroke symptoms— or if your arteries are at least 70% blocked but you do not have symptoms—your doctor may recommend that you undergo endarterectomy to reduce your risk of stroke. In this operation, a surgeon cuts into the carotid artery to remove fatty plaque and small clots that are clogging the vessel. The procedure has been shown to be highly effective. In people with severe carotid artery stenosis who have stroke symptoms or have already had a stroke, endarterectomy can cut the estimated two-year stroke risk by more than 80%. Like all surgeries, however, endarterectomy carries serious risks, and not everyone is a good candidate for this operation.
The recent approval of a carotid stent by the FDA now provides such patients with a less invasive alternative. In carotid stenting, a doctor inserts the stent, which is a slender metal mesh tube, into the carotid artery to increase blood flow in areas narrowed by plaque. Recent trials have produced some encouraging news about the efficacy of stenting, but the procedure is not risk free and it is not an option for everyone. In addition, because the recent trials involved relatively small numbers of patients, many experts are awaiting the results of a major study sponsored by the National Institutes of Health, called the Carotid Revascularization Endarterectomy vs. Stenting Trial (CREST), before recommending more widespread use of carotid stents.
Bruce Perler, M.D., Julius H. Jacobson II Professor of Surgery and Director, Division of Vascular Surgery at Johns Hopkins, comments, “Stenting works, and I certainly refer some patients for stenting. However, carotid endarterectomy is still the gold standard for treating carotid stenosis unless the patient has an anatomy that makes surgery more difficult or has significant medical risk factors, such as a recent heart attack.”
What carotid artery stenting entails
If you are a candidate for a carotid artery stent, your doctor will first perform a procedure in which a catheter is inserted into a blood vessel in the groin and then guided to the carotid artery. Once the catheter is in place, a small balloon is inflated for a few seconds in the narrowed portion of the carotid artery to flatten the plaque, and the stent is inserted. Acting like a scaffold, the stent props open the carotid artery and prevents it from reclosing once the blockage has been removed. Carotid artery stenting includes the use of a temporary filter that can help trap any particles of plaque or clot that are dislodged during the procedure and prevent them from traveling to the brain.
The FDA approved the first carotid artery stent (Acculink) and filter system in 2004, and a second type of carotid stent (Xact) and filter was approved in 2005.
What the research on carotid artery stenting shows
Several studies have now compared carotid artery stenting with endarterectomy in different groups of patients. In a 2004 study reported in The New England Journal of Medicine (NEJM), 334 patients with coexisting conditions that posed a high risk for surgery were randomly assigned to either carotid artery stenting or endarterectomy. When the rate of major adverse events, such as stroke, heart attack, or death, was assessed within 30 days and one year of the procedure, the results indicated that stenting was as effective as traditional surgery.
Another trial, reported in the Journal of Vascular Surgery in 2005, compared the two approaches in a broad population of patients with carotid artery stenosis—not just those at high surgical risk—and found no significant differences in the stroke and death rates at 30 days and one year between patients who received carotid artery stents and those who underwent endarterectomy. Although recent studies of carotid artery stenting have produced some positive findings, Dr. Perler cautions, "I think on balance I haven’t seen convincing data that stenting is superior, or even really equal, to endarterectomy." He also believes that the NEJM study had some serious flaws. "More than two thirds of the patients in this trial did not have symptoms, and according to American Heart Association guidelines, endarterectomy is not justified in such cases unless the stroke and death rate is lower than 3%. In this trial, the stroke and death rate with endarterectomy was a little over 6%—far worse than what we think is acceptable—so it’s easy to show that stenting is as good as that."
At this point, much more data are available on the efficacy and safety of carotid artery endarterectomy, so many doctors still consider this to be the best option for stroke prevention and have adopted a wait-and-see attitude to carotid stenting. The large ongoing CREST trial may eventually help settle the issue of what is the most appropriate role for stenting. This study is assessing the long-term effectiveness of carotid artery stenting and endarterectomy in 2,500 participants with carotid stenosis who are at normal risk for surgery and either have neurologic symptoms or are asymptomatic. Final results should be available in a few years.
What’s the right choice?
At present, carotid artery stenting is recommended for patients at high risk for surgical complications from endarterectomy who have more than 70% blockage in the carotid artery and have experienced symptoms of a stroke or ministroke. If you have no neurologic symptoms, you may also be a candidate if your carotid artery is severely narrowed (more than 80%) and you cannot tolerate surgery.
At this time, carotid stenting is not usually recommended for people over age 80. “And in fact most elderly patients can undergo endarterectomy as safely as younger patients,” Dr. Perler says. In addition, stenting may not be a good option if you have an irregular heart rhythm, an uncorrected bleeding disorder, or an allergy to the contrast dye used in the procedure. Finally, notes Dr. Perler, "I think a lot of people who are not experiencing symptoms but have moderate degrees of carotid stenosis (50% to 69% narrowing) probably are best served by being treated medically— with antiplatelet, antihypertensive, and cholesterol-lowering statin drugs. Statins, for example, have anti-inflammatory effects, can stabilize fatty plaque, and seem to have a benefit in long-term stroke prevention.”
Bottom line advice: Endarterectomy remains the procedure of choice for most people who have clogged carotid arteries. Carotid artery stenting may be a less invasive alternative to endarterectomy for people with significant carotid artery blockage who are at high risk for surgery or have anatomic features that would make surgery very difficult. Stenting is not a good option for patients 80 years of age or older, but many of these patients can safely undergo endarterectomy. You should check with your health insurer to determine whether your policy covers the cost of carotid artery stenting. Medicare only covers the procedure for high-risk patients who are experiencing neurologic symptoms and have greater than 70% carotid artery blockage.
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