THURSDAY, Sept. 13, 2007 (HealthDay News) -- A survey of trials of drug-coated stents finds that those coated with the medication siromilus appear to be somewhat safer than those coated with another drug, paclitaxel.
Analysis of 38 trials involving more than 18,000 participants suggest that "sirolimus-eluting stents appear to have the best overall profile, if you look at the entire picture," said lead researcher Dr. Peter Juni, head of the division of clinical epidemiology and biostatistics at the University of Bern in Switzerland.
There was one caveat, however: According to Juni, the studies were so varied in the types of patients given stents -- tiny mesh tubes that prop open arteries -- that it's not possible to say that everyone would be better off with a siromilus-coated model.
"We need to better understand if there are subgroups that benefit more from siromilus-eluting stents or perhaps subgroups that do not benefit at all from them," he said. "Future studies need to address the problem of the patient spectrum."
The difference was confined to the risk of heart attacks and restenosis -- a re-blockage of the reopened artery -- after the stents were implanted, said the report, which is published in the Sept. 15 issue of The Lancet.
The researchers also noted that the patient death rate was the same for those who got either one of the more expensive drug-coated stents, or a bare-metal stent.
However, the incidence of heart attacks was 19 percent lower in those getting a siromilus-coated stent than those getting a bare-metal stent, the team found. Heart attack risk was 17 percent lower in those getting the paclitaxel stent compared to the use of bare-metal devices.
The report may help settle the ongoing battle between the two stents, "mainly because the data set is so big," said Dr. Kirk Garratt, clinical director of interventional cardiovascular research at Lenox Hill Hospital in New York City. However, he agreed with the authors that "this mix of patients is really troubling. We need to isolate out subsets of patients."
The analysis included groups that differed widely, Garratt noted. "For example, there were 10 percent women in one trial, 80 percent in another," he said. "It seems troubling to make sweeping statements about safety on such widely varying patient populations."
Recent changes in cardiology practice may have also undermined the report's importance, Garratt added. Worries about restenosis surfaced about a year ago, he said, and have led to changes in medical practice. But the new analysis largely includes studies done before then.
"Our effort to reduce stent clotting is paying off," Garratt said, mostly through a concentration on dual therapy involving clot-preventing medications. Cardiologists are now very careful to have stent recipients take both Plavix and aspirin, which act on blood platelets to prevent clotting, he said.
"This report could mistakenly be taken in such a way to make someone choose product A over product B," Garratt said. "The power of observation in the study is not enough to make that sweeping of a change."
The use of drug-coated stents is also being limited, at least in his practice, said Dr. Joseph B. Muhlestein, professor of medicine at the University of Utah, Salt Lake City. "If the patient has a low risk of restenosis, we get by with a bare-metal stent," he said.
Muhlestein found some comfort in the relatively low rate of deaths and complications described in the report. "The situation perhaps is not as bad as we worried," he said.
Muhlestein's group has been working on its own safety analysis of drug-coated stents, he added. "The data do not go against the belief that the siromilus stent might be safer than the paclitaxel stent," the expert said.
You can learn how a stent works by going to the American Heart Association.