Expensive, Drug-Coated Stents Offer Modest Benefit
Based on studies, bare-metal stents may be just as good, experts say
WEDNESDAY, Sept. 13, 2006 (HealthDay News) -- Two new studies fail to answer a burning question for heart patients and cardiologists: Are high-tech, drug-eluting stents worth the added expense?
The studies compared the two leading drug-coated stents to more conventional -- and cheaper -- bare-metal models.
Reporting in the Sept. 14 issue of the New England Journal of Medicine, researchers found that only one of the artery-opening devices -- the "Cypher" sirolimus-eluting stent -- offered heart-attack patients a modest health benefit over the course of one year.
Even then, "I don't think that these studies should be used to try and compare one [drug-eluting] stent to another," said Dr. Sid Smith, a former president of the American Heart Association and a professor of medicine at the University of North Carolina at Chapel Hill.
"In order to make a real comparison, we need to have a head-to-head trial," Smith said -- and that hasn't happened yet.
Another expert agreed.
The studies offer no evidence of the "superiority of one [stent] over the other," said Dr. Frans Van de Werf, professor and chairman of the department of cardiology at University Hospital Gasthuisberg, in Leuven, Belgium. Van der Werf is also the author of a related editorial in the journal.
Surgeons use the tiny wire-mesh tubes called stents to help prop open narrowed arteries after angioplasty, an artery-clearing procedure. However, over a period of months or years, patients are often threatened by a process called restenosis -- a re-narrowing of the artery around the stent.
Drug-eluting stents, which cost about $2,000 each, are impregnated with specific medicines that may help prevent this process.
Since their introduction in the late 1990s, the two leading drug-eluting stents -- Cordis Inc.'s Cypher and Boston Scientific's Taxus -- have battled it out in various efficacy trials. The Cypher stent emits a drug called sirolimus, while the Taxus model releases another drug, paclitaxel.
In one trial published in this week's NEJM, a team of Dutch researchers compared the Taxus stent to bare-metal stents, looking at their effectiveness in warding off cardiac death, recurrent heart attack or vessel re-closure. A total of 619 patients, all of whom had received a stent after a heart attack, were included in the trial.
According to the researchers, there was no statistically significant difference in the rate of "serious adverse cardiac events" between the two patient groups during 12 months of follow-up.
In a second trial, a multi-center team of European investigators compared the eight-month outcomes of 712 heart-attack patients who received either the Cypher device or a bare-metal stent.
This time reductions in risk did reach statistical significance: 7.3 percent of Cypher patients experienced a serious cardiac event over the course of a year, compared to 14.3 percent of patients who got a bare-metal stent.
Still, the trials were too short to come to any definite conclusions, Van de Werf said. He believes that what's really needed are "direct comparative trials of uncoated vs. drug-eluting stents, with long follow of more than one year."
Smith, who is also chairman of the joint American College of Cardiology/American Heart Association Task Force on Practice Guidelines, said longer trials would help determine the safety of coated stents, too.
"Right now, there's a big argument about whether or not [patients with] drug-eluting stents are actually more prone to having clots or problems with them after one year -- maybe they are not as safe as bare-metal versions over the long-term," Smith said.
One recent study, conducted by Boston Scientific, did find an increase in clotting among Taxus recipients compared with those patients receiving bare-metal stents. The risk of clotting began to rise six months after patients received the stent, the company said.
Longer-term safety data isn't yet available, however. So, in the meantime, Smith provides most of his patients with a drug-eluting stent plus a blood-thinner, such as clopidogrel (Plavix).
According to Smith, the two studies published this week only prove that drug-eluting stents are equal in efficacy to cheaper, bare-metal versions -- "at least for this short period of up to one year." For many patients, the added cost of the coated devices may help guide treatment choices.
Devices like Cypher and Taxus may be an improvement over bare-metal models for certain patient subgroups, Smith added.
"For instance, chronic patients with diabetes might have a better outcome with a drug-eluting stent, or those with long lesions in their vessels or more narrowed vessels," Smith said. "In studies, it looks like results are better with drug-eluting stents."
Find out more about drug-eluting stents at the U.S. Food and Drug Administration.