TUESDAY, Jan. 11, 2005 (HealthDayNews) -- Since the 1990s, cardiologists have used tiny wire mesh tubes called stents to help keep arteries open following angioplasty.
But when an artery closes after a stent has been implanted, it's more effective to replace it with another stent coated with a clot-preventing drug than to perform another angioplasty, a new German study finds.
The researchers, who looked at two types of stents coated with different drugs, found one type was more effective than the other. But each produced better results than angioplasty, which clears arteries by using an inflated balloon.
Arteries remained blocked in 41 of 92 patients -- or 44.6 percent -- who underwent angioplasty, the doctors reported. Blockage occurred in only 13 of 91 patients -- 14.3 percent -- given stents coated with a drug called sirolimus, and 20 of 92 patients -- 21.7 percent -- who got stents coated with the drug pacliatexel.
The study is important because it provides the first solid evidence to support what cardiologists in the United States have been doing for some time, said Dr. Stephen G. Ellis, director of the cardiac catheter laboratory at the Cleveland Clinic Foundation. "It is a step forward, but it doesn't answer all the questions we have," he said.
The study appears in the Jan. 12 issue of the Journal of the American Medical Association.
The German study is a beat behind medical progress because all the patients had bare metal stents implanted originally, Ellis noted. "About a year and a half ago, we stopped using bare metal stents, and began using drug-eluting stents," he said. "The relevant question in the United States is whether these findings apply to restenosis [closing of the artery] after implant of a drug-eluting stent."
Artery blockage happens in about 20 percent of patients who receive a bare-metal stent and 10 percent of those who receive coated stents, Ellis said. If the problem does occur, it generally happens from 12 to 18 months after the original stent implantation, he said.
In cases where blockage occurs in coated stents, cardiologists have been playing it by ear, Ellis said. "If the patient has a sirolimus-coated stent, we will use a pacliatexel stent, and vice versa," he said. "The decision is based partly on intuition, with not a whole lot of science involved."
One major change in treating clogged arteries has been the virtual abandonment by U.S. doctors of a third method, brachytherapy, in which a source of radiation is implanted to reopen the artery, Ellis said. "Use of brachytherapy has plummeted, and at least two of the three companies that had been making the devices have stopped," he noted.
However, brachytherapy is not dead in Europe, said study author Dr. Adnan Kastrati, a professor of cardiology at the Deutsches Herzzentrum in Munich.
"There are at least two running trials comparing drug-eluting stents with brachytherapy," he said, adding he has "no information about when these trials will become available."
The new study has changed medical practice at his institution, Kastrati said. "We are now using only drug-eluting stents for in-stent restenosis," he said.
You can learn more about stents from the American Heart Association.