Drug-releasing stents used widely to keep clogged heart arteries open may increase the risk of potentially dangerous blood clots, but there is no conclusive evidence that the devices boost the likelihood of having a heart attack or dying if used as recommended, an expert panel said Thursday.
The conclusion by a special Food and Drug Administration panel should be reassuring to hundreds of thousands of patients who have the tiny mesh struts, known as drug-eluting stents, which have become the most commonly used devices for treating partially blocked arteries.
"The message is: Drug-eluting stents are safe, and the safety concerns are far outweighed by the evidence of a clinical benefit," said Dr. William Maisel of the Beth Israel-Deaconness Medical Center in Boston, who led the 21-member panel.
Maisel and others cautioned that the reassuring conclusion applied only to patients for whom the devices were originally approved. At least 60 percent of those currently getting them are sicker patients, and for them the risk-benefit calculus may be different. The panel will consider that issue today.
The discussion revealed deep disagreement and uncertainties among the FDA advisers. The panelists agreed there was insufficient evidence to conclude that the overall risk of heart attacks and death was greater among those getting the drug-eluting stents compared to those who received older, bare-metal versions. But the panel was divided about whether the devices increased the risk of clots. And some panel members remained concerned about the long-term safety of the devices, which have been implanted in an estimated 2-million to 3-million Americans.
"I have seen nothing to date that indicates that the problem goes away," said Dr. Steven Nissen, president of the American College of Cardiology.
Questions about the safety of the devices has been the subject of intense attention because the number of people getting them has risen dramatically since they were introduced in 2003. Worldwide, an estimated 6-million people now have stents, and about 800,000 Americans get them each year.
The debate came on the opening day of an urgent two-day meeting the FDA convened to evaluate the issue. Hundreds of people packed a large Gaithersburg, Md., meeting room outside Washington for the highly anticipated session, including representatives from Johnson & Johnson and Boston Scientific Corp., which make the two brands of drug-eluting stents sold in the United States.
The companies presented data they said indicated that any increased risk for blood clots was offset by the devices' ability to sharply reduce the need for surgical treatment, which carries its own risks.
The FDA is not bound to adopt the panel's recommendations but usually does.