Carotid Artery Surgery Brings Higher Than Expected Risk

THURSDAY, Feb. 8, 2007 (HealthDay News) -- A procedure designed to clear blockages from the neck's carotid arteries appears to be riskier in real life than it seemed in clinical trails, researchers report.

The procedure, called carotid endarterectomy, "is the most common surgery performed to prevent stroke," noted study author Dr. Seemant Chaturvedi, a professor of neurology and director of the Wayne State University Stroke Program in Detroit.

"Previous studies have found that the risk/benefit ratio of the surgery is fairly narrow. There is a fine line of providing benefit to the patient and not providing benefit," he said.

That line may have been crossed for some patients, according to the new study, which was expected to be presented Thursday at the American Stroke Association annual meeting in San Francisco.

In carotid endarterectomy, surgeons open up clogged carotid vessels, pull out accumulated plaque, then suture the artery up again.

In their study, Chaturvedi and colleagues collected data on carotid endarterectomies performed in two Detroit hospitals.

One hospital performed 99 carotid endarterectomies during the study period, the other performed 51. Among all patients, 69 percent had no symptoms before undergoing the procedure. About 60 percent of the patients were black. Many patients in the study had high blood pressure, diabetes or smoked, Chaturvedi said.

The team found significantly more complications associated with the surgery -- particularly among black patients -- than expected.

For people without symptoms, the complication rate in terms of suffering a stroke or dying during the procedure should be less than 3 percent, Chaturvedi said. And "the majority of carotid endarterectomies are done on asymptomatic patients -- 70 to 80 percent," he noted.

However, the researchers pegged the rate of stroke during carotid endarterectomy at 4.7 percent, while the expected rate was 3.1 percent. The rate of heart attacks was 6.7 percent; however, the expected rate was 0.4 percent.

The combined rate of stroke and heart attack at the time of carotid endarterectomy was 11.3 percent, which is more than three times the expected rate of 3.5 percent. Chaturvedi noted that many patients were over 75, and most of the heart attacks and strokes occurred in this group.

Before doing this procedure, doctors should be sure that patients, particularly black patients, have their blood pressure controlled. "I would be a little hesitant about operating on the asymptomatic ones, because those are the patients who have the most narrow risk/benefit ratio, especially the asymptomatics over 75. I would probably refrain from operating on them," Chaturvedi said.

Chaturvedi also said that practice makes perfect, so that the more a doctor does the procedure, the better he or she gets. Likewise, the more procedures a hospital does, the lower the risk of complications. For example, the hospital that did 99 procedures had fewer problems than the one that did only 51, he said.

One expert believes the procedure is too risky for patients with asymptomatic carotid artery disease.

"That the results are worse in the real world than in a selected clinical trial population may also apply to populations that are not African-American," said Dr. Vladimir Hachinski, a professor of neurology at the University of Western Ontario, London, Canada. "It wouldn't be surprising if the real figures are closer to Detroit than reported clinical trials."

"The procedure is more dangerous than reported," Hachinski said. "It's particularly dangerous in asymptomatic carotid disease, where any gain is marginal, because the risk of having a stroke from asymptomatic carotid disease is only 2 to 3 percent a year," he added.

Hachinski said his hospital does not perform the procedure on asymptomatic patients.

The Canadian expert also believes that before they have a carotid endarterectomy, patients should gather a lot of information about the risk vs. the benefits. They should also investigate the experience and the success rate of their doctor and their hospital.

"Ask what the statistics are for that hospital," Hachinski said. "Show me the money--what are my odds?"

More information

There's more on carotid endarterectomy at the American Heart Association.