FRIDAY, Aug. 13, 2004 (HealthDayNews) -- The new drug-coated stents -- flexible tubes designed to keep arteries open -- have some major advantages over the older generation of bare-metal stents but don't do better at reducing the risk of heart attacks or death in the months after they are implanted, a new study finds.
Analyzing data on 11 trials that compared results in 5,000 patients who got either bare-metal and drug-eluting stents, as they are formally known, researchers at McGill University in Montreal say the newer devices reduce the risk that arteries will close up again and the occurrence of "major adverse cardiac events," such as the need to perform bypass surgery.
"However, as with bare-metal stents, there is no evidence that drug-eluting stents have any effect on medium-term mortality or rates of myocardial infarction [heart attack]," said a report in the Aug. 14 issue of The Lancet.
A stent is implanted after balloon angioplasty, a procedure that widens arteries in which blood flow is impeded by fatty deposits. Coated stents, which release drugs that help keep arteries open, were introduced about five years ago and are now widely used.
All the studies analyzed in the report were relatively short-term, following patients for six to 12 months. Drug-eluting stents did reduce the rate of major adverse cardiac events by more than half, to just 7.8 percent compared to 16.4 percent for bare-metal stents, the study found. And the rate at which arteries began to close was reduced even more dramatically, from 29.3 percent for bare-metal stents to 8.9 percent for the drug-coated kind.
But the overall death rate and the incidence of heart attacks were almost identical for patients who got the coated or bare stents, the analysis found.
An accompanying editorial by Dr. Joachim Schofer, a cardiologist at the Center for Cardiology and Vascular Intervention in Hamburg, Germany, expressed cautious optimism about the results but observed dryly that longer-term studies are needed "before drug-eluting stents deserve the term 'panacea.'"
It's not surprising that the analysis found no effect on the risk of death because "major events frequently are associated with disease in other arteries that do not receive stents," said Dr. Sidney Smith, chief of cardiology at the University of North Carolina and a spokesman for the American Heart Association.
It is a "very helpful study because it demonstrates the benefits of drug-eluting stents over the short term," Smith said. "If you have a drug-eluting stent, you are less likely to go back to the hospital because of restenosis [artery blockage] or an adverse cardiac event."
But the failure to find an impact on the risk of death or heart attack over the short term is likely to persist when longer-term studies are done, unless steps are taken against the known risk factors such as high cholesterol, high blood pressure and smoking, he said.
"The major effect on mortality comes from reducing risk factors," he said. "To make a difference, you have to reduce those risk factors and not count on a drug-eluting stent."
Learn about stents at the American Heart Association.