FRIDAY, Dec. 8, 2006 (HealthDay News) -- In the face of incomplete evidence on the safety of drug-coated stents in the real world, a panel of U.S. heart experts said Friday that the devices should stay on the market, but with certain caveats.
The U.S. Food and Drug Administration panel charged with investigating the safety of such stents said that all patients receiving the devices are at heightened risk for blood clots, and that many patients receiving the devices are at risk for heart attacks and death.
But there isn't enough evidence to say if the danger of heart attacks and strokes is due to the devices or the patients' poor health, the panelists added.
The group also noted that the data on the danger of off-label use was inconclusive, and that patients receiving drug-eluting stents should receive blood thinners for at least a year after the procedure.
"We feel that there are significant uncertainties, and it is difficult to make conclusive judgments regarding this issue," panel chairman Dr. William Maisel, of Beth Israel Deaconess Medical Center in Boston, said during the hearing, according to the Associated Press.
The panelists did recommend that the labels on the devices be updated to warn doctors that off-label use won't produce the same results as seen in generally simpler cases involving healthier patients, the wire service reported.
Experts noted the lack of information on the safety of coated stents poses a serious problem.
"The first question was [whether] there's a huge safety signal that should take stents off the market, and it sounds like they're comfortable that evidence was not strong enough for anything like that," said Dr. Kevin Schulman, director of the Health Sector Management Program at Duke University, in Durham, N.C.
"This reflects an uncertainty about the level of evidence, which is unfortunate given the number of people who receive procedures each year," he added. "There's a real need to get better evidence very quickly to answer these questions."
Of particular concern are the number of people , about 60 percent of total patients, who receive the devices off-label. On-label use is limited to no more than two stents; off-label covers three or more.
"The label is fairly narrow, so most are getting it off-label," Schulman explained. "Most are getting multiple stents in one single procedure, and the original clinical trials didn't cover all of those uses."
One expert said he was concerned that the FDA was sidestepping the issue of off-label use.
"This is a most compelling and overriding public health concern that the FDA has not been willing to tackle head-on," said Dr. Robert Michler, director of the heart center at Montefiore Medical Center/Albert Einstein College of Medicine in New York City. "The stents have clearly demonstrated a reduction in restenosis rates, but the question is: at what price?"
There may actually be two prices being paid, Michler added, one being the immediate risk of blood clots and the other the fact that patients are lulled into believing that their survival rates are being improved.
"There is no evidence to support that," he said. "There has never been demonstrated a survival benefit with stents when compared to the gold standard, which is bypass surgery. If stents are being applied to patients with multi-vessel disease or single vessel disease with decreased heart function, this is being done as an off-label use because there's no evidence to support that as a lifesaving therapy."
During Friday's hearing, the second in two days, the 21 panel members, who didn't take formal votes, stated their opinions and recommendations individually or reached informal agreements on positions as a group, according to Bloomberg News. The FDA usually heeds the recommendations of its outside advisers, though it isn't required to do so.
The key issue has been whether drug-coated stents, which have become dominant tools in the field of cardiovascular surgery since their introduction three years ago, create a heightened risk of potentially fatal blood clots. An estimated 6 million people worldwide have received the devices, 3 million of them in the United States.
The drug-coated stents release medicine designed to limit the incidence of arteries reclosing after angioplasty. The problem of reclosing is more frequently seen with traditional bare metal stents. And re-closures require repeat surgery.
A number of recent studies have suggested that drug-coated stents, which can cost thousands of dollars each, have long-term dangers -- most specifically, the risk of clots that could cause heart attacks. According to some estimates, drug-coated stents may cause an extra 2,160 deaths in the United States each year.
The advisory panel's recommendations on the use of blood thinners are unlikely to change real-world practice and may even be inadequate, experts said.
"We've always recommended that patients be on aspirin and Plavix [a blood thinner] for one year, and in the subgroups that are at the highest risk for other problems continuously after that," said Dr. Scott Monrad, director of the cardiac catheterization lab at Montefiore Medical Center in New York City.
"Patients have to understand that they may have to stay on blood thinners a minimum of one year, but maybe for the rest of their lives," Schulman added.
There is also concern that stents are being used when conventional bypass surgery should really be used.
"This has made us a little more sober in recognizing that there are risks that go with the procedure, and we shouldn't be careless," said Monrad. "In some patients, bypass surgery may very well be the preferred approach."
At the same time, Monrad emphasized, stents have completely eliminated restenosis as a medical problem.
"That is a dramatic change in practice," he said. "When we fix something now, in virtually every patient it stays fixed."
And, overall, the incidence of problems is still very low, he added.
Visit the American Heart Association for more on stents.