Stents Called Too Risky for Stroke Prevention
The increasingly common practice of preventing strokes by using wire mesh stents to prop open neck arteries is much riskier than the traditional method of surgically removing plaque and should be curtailed, according to two large European studies.
Patients receiving the stents were nearly 2 1/2 times as likely to have a stroke or die, French researchers reported today in the New England Journal of Medicine. The results were so clear, the researchers said, that they terminated the study prematurely and stopped using the stents.
In a larger German study reported earlier this month, researchers found a smaller, but statistically significant, increased risk associated with the stents and also called for a halt to their use.
“Stenting has been touted as a reasonable alternative to surgery, but there is no convincing data that stenting is even equivalent to surgery,” said Dr. Mark J. Alberts, a neurologist at Northwestern University Medical School who was not connected to either study.
“Endarterectomy [surgery] should remain the treatment of choice,” he said.
Some American researchers said the findings were in conflict with U.S. studies that showed that the stents were safer than surgery.
Researchers on both sides are at a loss to explain why the findings are so different. Most agree, however, that a definitive conclusion may not be available until the completion of other studies, including a large study sponsored by the National Institutes of Health.
“The jury is still out,” wrote Dr. Anthony Furlan of the Cleveland Clinic in an editorial accompanying the French study.
But Dr. Eric Topol of Case Western Reserve University, who was not involved in the research, said the two recent studies should significantly slow down stenting procedures, which should not be used except in patients too sick for surgery.
About 700,000 Americans suffer strokes each year, and the largest fraction of them are caused by the buildup of plaque in the carotid arteries that provide blood to the brain.
The plaque can build up to the point where it completely blocks blood flow, or pieces can break off and lodge in smaller vessels in the brain, triggering strokes.
The gold standard for treatment of the condition is surgery to remove plaque from the blood vessels, a process called carotid endarterectomy. About 150,000 of the procedures are performed in the U.S. annually.
Two years ago, the Food and Drug Administration approved stents designed for use in the carotid arteries. Like the larger stents used in coronary arteries to prevent heart attacks, the new stents compress the plaque and hold the artery open.
No one knows how many carotid artery stenting procedures are done each year, but they are growing in favor because they are less invasive, require a shorter hospitalization and are cheaper. The procedure involves inserting a catheter through the groin under heavy sedation and threading it to the affected blood vessel, where the stent is placed.
The use of the stents was expected by many analysts to become a $1-billion-a-year business.
The French study at 30 medical centers, led by Dr. Jean-Louis Mas of the Sainte-Anne Hospitals in Paris, enrolled 527 patients who had at least a 60% blockage of the carotid artery. The patients all displayed symptoms, such as weakness of arms or legs, slurring of speech, loss of vision, and confusion.
Half underwent stenting and half received an endarterectomy.
At the end of six months, 11.7% of the patients who received a stent had suffered a stroke or died, compared with 6.1% of the patients who underwent an endarterectomy.
The study was sponsored by the French Ministry of Health.
The German study, reported in the medical journal Lancet, enrolled 1,183 patients who were also suffering symptoms from their blockage. Dr. Werner Hacke of the University of Heidelberg and his colleagues at 35 medical centers found that after one month, 6.51% of those receiving a stent suffered a stroke, compared with 5.14% of those receiving an endarterectomy.
The trial, which was also halted early, was sponsored by several government and private agencies, as well as the companies that manufacture the stents. Hacke reported that he had received fees from Sanofi-Aventis, one of those companies.
The European results “are surprising given that the death and stroke rate after stenting seems higher than in previous U.S. studies,” said Dr. Spencer King of the Fuqua Heart Center in Atlanta and a past president of the American College of Cardiology.
A U.S. study of 334 patients found that 20.1% of those receiving endarterectomies had a stroke or a heart attack or died in the year after surgery, compared with 12.2% of those receiving stents.
One possibility, Furlan noted, is that many of the patients in the American studies did not display symptoms and thus were less likely to suffer adverse events after stenting.
Another possibility is that the French surgeons were better at performing endarterectomies, King said.
Their death and stroke rates for the surgery were significantly lower than those observed in other studies.
Conversely, the surgeons who performed the stenting were less experienced.
Many had only done the procedure twice before the start of the study, and their technique might have been inadequate.
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denise.gellene@latimes.com
