May 6, 2009 -- Heart patients treated with drug-coated stents to open clogged arteries are no more likely to die than patients treated with non-drug-coated stents, and they have a lower risk of having their arteries renarrow, two studies show.
The studies should help calm fears raised several years ago about the safety of drug-coated stents, also called drug-eluting stents, which have been linked to an increased risk for blood clots.
In one study, patients who got stents during a heart attack that were coated with the drug paclitaxel were less likely than patients treated with bare-metal stents to need repeat procedures over the next year to reopen a treated artery.
In another study, which followed everyone in Sweden who got stents between 2003 and 2006, treatment with drug-coated stents was also associated with a lower risk of having treated arteries renarrow -- a condition known as restenosis.
Death Rates for Stents
Death rates were similar in both treatment groups in both studies, which appear in the May 7 issue of the New England Journal of Medicine.
A third study, presented at a meeting of the American College of Cardiology, compared outcomes among 262,700 Medicare patients across the U.S. treated with drug-coated or bare-metal stents.
In that trial, treatment with a drug-coated stent was associated with a slight decrease in deaths and nonfatal heart attacks.
Cardiologist Glenn N. Levine, a spokesman for the American Heart Association, tells WebMD that the latest studies have reduced, but not eliminated, concerns about the safety of drug-coated stents.
Levine is a professor of medicine at Houston's Baylor College of Medicine and directs the coronary care unit at Baylor's Michael E. DeBakey Medical Center.
"It is certainly reassuring that in these large registries, as well as the large randomized trial, we do not see any significant increase in death or even a signal for an increase" associated with drug-coated stents, he says.
Drug-coated stents are essentially normal metal stents treated with a drug designed to help prevent arteries from reclogging.
In 2007, researcher Stefan K. James, MD, and colleagues studying outcomes among Swedish heart patients were among the first to confirm a link between coated stents and potentially life-threatening blood clots.
"We found warning signs of an increase in mortality among patients treated with the drug-eluting stents in patients followed for up to three years," James tells WebMD.
In their latest analysis, the researchers followed patients for up to five years and found little difference in mortality among those treated with drug-coated and non-drug-coated stents.
Swedish patients who were among the first to get the drug-coated stents did have higher death rates than patients treated with bare-metal stents, and James thinks he knows why.
"I think we were overly optimistic when we started using drug-eluting stents," he says. "We thought that everything could be solved with them and we started stenting very sick patients."
These days, patients are more carefully selected, and drug-coated stents are used only in those who are able to take blood-thinning drugs to reduce the risk of clotting.
Patients in the Swedish study who got the drug-coated stents were less likely to have their treated vessel reclog. This was especially true among high-risk patients, including those with diabetes, small vessels, and long or complicated blockages, James says.
Stents and Renarrowing of Arteries
In the U.S., roughly three out of four stent-treated patients receive the drug-coated devices, Gregg W. Stone, MD, of Columbia University tells WebMD.
In their newly reported trial, Stone and colleagues followed 3,006 patients treated with stents during a heart attack for a year.
Three-fourths of the patients received stents treated with the drug paclitaxel and the rest got bare-metal stents. The study was funded, in part, by drugmaker Boston Scientific, which makes the drug-coated stent used in the study.
The analysis revealed that:
- Restinosis leading to recurrent chest pain, hospitalization, and repeat artery-opening procedures was reduced by 41% in the drug-coated stent group.
- Renarrowing of the treated artery, as measured by an angiogram, was reduced by 56% in patients treated with the drug-coated stents.
- Rates of death, second heart attack, and stroke were not significantly different between the two groups.
Stone says angioplasty, bare-metal stents, and drug-coated stents are equally effective for saving lives during a heart attack.
But he says it is increasingly clear that drug-coated stents offer advantages to patients who can take blood-thinning drugs to reduce their risk for blood clots.
"In our study, drug-eluting stents did not seem to reduce death rates, but they did reduce the incidence of renarrowing of the arteries," Stone says. "That means less chest pain, less hospitalization, and fewer repeat procedures."