Drug-coated stents, the coil-like metal devices that prop open blocked arteries, appear to be superior to older bare-metal stents for treating heart attacks, according to a new study.
The finding is the first randomized trial showing a clear benefit with drug-coated stents in an emergency setting, although some doctors already have been using the revolutionary devices to treat heart attacks.
"Our study extends previous knowledge showing that ... drug-eluting stents are more effective and probably are as safe as bare-metal stents," said lead author Marco Valgimigli, chairman of cardiology at the University of Ferrara, Cardiovascular Institute in Ferrara, Italy.
Several trials have shown that drug-coated stents can significantly lower the incidence of arteries reclogging after angioplasty is performed in patients with so-called stable coronary artery disease.
The new study, appearing Wednesday in the Journal of the American Medical Association, found that heart attack patients treated with a drug-coated stent had substantially lower rates of arteries reclogging than those treated with a bare-metal stent.
"This study is very, very reassuring," said Tanvir Bajwa, an interventional cardiologist at St. Luke's Medical Center in Milwaukee. "I think this study will open up eyes."
While many doctors already are using drug-coated stents in heart attack patients, some have been reluctant to because of a concern that the devices might cause thrombosis, a type of clot that can form quickly within the stent, he said. Although such clots occur infrequently, they often are fatal.
Bajwa said St. Luke's just completed its own study of 134 heart attack patients who got the same drug-coated stent used in the JAMA study. It found that the rate of thrombosis was 0.5 percent, about the same as the rate with bare-metal stents, he said.
Since they were approved in 2003, use of drug-coated stents to treat stable coronary artery disease has skyrocketed. There are two Food and Drug Administration-approved drug-coated stents on the market, Cypher and Taxus.
Both stents are coated with a polymer and anti-rejection medications that are released slowly to prevent the overgrowth cells that could cause a reblockage of the artery.
The Cypher device is coated with a drug known as sirolimus. The Taxus device is coated with paclitaxel. Both devices are inserted into arteries using a catheter and are opened when a balloon is inflated during angioplasty.
The new study, which involved 175 Italian heart attack patients, compared the sirolimus stent and an anti-clotting drug with a bare-metal stent and a different anti-clotting drug.
Eight months after the stents were implanted, the rate of reblockage with the sirolimus stent was 9 percent, compared with 36 percent for the bare-metal stent.
The study provides evidence for what many have suspected, that drug-coated stents also are beneficial when treating heart attack patients, said Terry Zarling, chairman of the department of cardiology at Waukesha (Wis.) Memorial Hospital.
"We've been using the [drug-coated] stents that way," Zarling said. "It's nice to have a study showing the hypothesis is accurate."
Waukesha Memorial is one of about 60 U.S. hospitals taking part in a clinical trial of a third drug-coated stent, the Endeavor coated stent, although that device is being tested only in patients who have not had heart attacks.
Even though the Italian trial is relatively small, it provides encouraging evidence that a drug-coated stent is superior to a bare-metal stent in treating heart attack patients, said E. Magnus Ohman, a professor of medicine at the University of North Carolina at Chapel Hill and co-author of an editorial accompanying the study.
Ohman said larger trials comparing bare-metal and drug-coated stents now are under way, but it's going to be hard to tell heart attack patients they should not get a drug-coated stent.
