May 6 (HealthDay News) -- Although arteries propped open by drug-coated stents are less likely to become blocked again than those treated with bare-metal stents, the risk of death and heart attacks is virtually identical between the two devices, major studies in Sweden and the United States show.
The Swedish results eliminate concerns raised by an earlier study that the drug-coated stents might actually be more dangerous, said Dr. Stefan K. James, an associate professor of cardiology at Uppsala University and lead author of the Swedish study appearing in the May 7 issue of the New England Journal of Medicine.
The earlier study, of Swedes given stents in 2003 and 2004, found a higher death rate among those who got the drug-coated kind. The follow-up study of 47,967 Swedes who had stents implanted between 2003 and 2006 found "no overall difference between the group that received drug-eluting stents and the group that received bare-metal stents in the combined endpoint of death or myocardial infarction [heart attack]," the report said.
But the rate of re-stenosis -- new blockage of the treated artery -- was three per 100 patient years versus 4.7 for the bare-metal recipients.
So the earlier result was "just a scary signal" that proved to be false, James said.
"For me, this paper shows that there should now be no real concerns about the safety of drug-eluting stents and that the emphasis should shift back to considering the relative efficacy of drug-eluting stents and bare-metal stents," Dr. Eric Eeckhout, a spokesman for the European College of Cardiology, said in a statement.
James's interpretation of the study is that use of drug-coated stents should be limited to cases where the risk of re-stenosis is high -- when the blockages are in smaller blood vessels and are long in length and when the person has diabetes, for example.
Cost plays a role in his judgment, James said. "The prices of drug-coated stents have gone down in Europe, but they cost twice as much here [in Europe] as the bare-metal stents," he said.
And the study results are not definitive because they did not come from a randomized, controlled trial, the gold standard of medical research, James said.
The American study, reported in the same journal, was such a controlled trial. It included 3,006 people given stents after heart attacks, comparing outcomes for the 2,257 who got Taxus stents, coated with the drug paclitaxel, with the 749 who received bare-metal stents.
Unlike the Swedish trial, which was funded by governmental and noncommercial organizations, the American trial was supported by Boston Scientific, which markets the Taxus stent.
Again, the rate of re-stenosis was significantly lower in the group given a coated stent: 10 percent versus 22.9 percent in the first 13 months. There was an identical 12-month death rate, 3.5 percent, in both groups, and no difference in the incidence of serious cardiac problems, such as second heart attacks.
It's not surprising that there was no lifesaving benefit to the drug-eluting stent, said study author Dr. Gregg W. Stone, a professor of medicine at Columbia University Medical Center.
The procedure done in the study was the reopening of the blocked artery that caused the heart attack, Stone said. "What keeps them alive is whether or not they have another heart attack," he said. "We don't expect them [the stents] to save lives."
He was strict in drawing a conclusion from the trial: "What this study shows is that this paclitaxel-eluting stent is safe to use in patients with an evolving heart attack, and that it reduced the incidence of re-stenosis by about 40 percent."
That conclusion cannot be extended to other drug-coated stents because "drug-eluting stents are different from each other," Stone said. Another controlled trial would be needed to determine whether the differences are significant in ultimate results, he noted.
SOURCES: Stefan K. James, M.D., Ph.D., professor, cardiology, Uppsala University, Sweden; Gregg W. Stone, M.D., professor, medicine, Columbia University Medical Center, New York City; May 7, 2009, New England Journal of Medicine