WEDNESDAY, Oct. 4, 2006 (HealthDay News) -- A new Italian study appears to pick a winner from two widely used, expensive drug-coated stents that are used to prop open ailing arteries.
Researchers conclude that Cypher, a wire-mesh stent coated with sirolimus, made by Cordis Inc., is better for patients than a competing stent, Taxus, made by Boston Scientific and coated with another drug, paclitaxel.
The team reported their findings in the October issue of the Journal of the American College of Cardiology.
However, some cardiologists said the finding is less than definitive, adding that the short (one-year) length of the trial doesn't even prove that coated stents are superior to cheaper bare-metal stents.
The real problem is that cardiologists who use stents are reporting an unexpectedly high rate of artery re-closure over time, said Dr. Steven Nissen, chairman of the department of cardiovascular medicine at the Cleveland Clinic and chairman of the American College of Cardiology.
"We need more data on long-term outcome," he said. "I'm calling for a study with a four- or five-year follow-up."
Dr. Bradley H. Strauss, director of interventional cardiology at St. Michael's Hospital in Toronto, wrote an accompanying editorial on the finding. He expressed some confidence that the Cypher stent is, indeed, slightly superior to the Taxus model.
But Strauss also agreed with Nissen that longer, controlled trials are needed, adding that "there still is some basis on which one could say that it is absolutely not clear which [stent] is better."
Another expert, Dr. Sidney Smith, a professor of medicine at the University of North Carolina, concurred that more study is necessary to settle the issue. "What is really needed is a head-to-head study that is randomized. Another thing I'd like to see is follow-up beyond one year," he said.
Surgeons use 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 -- Cypher and Taxus -- have battled it out in various efficacy trials. Two recent studies, published in September in the New England Journal of Medicine, failed to find a clear-cut winner, although researchers gave a slight edge to the Cypher device.
In this study, cardiologists working at a number of Italian medical centers performed a head-to-head study of the two stents. A total of 1,676 patients received the devices after angioplasty.
The team found that the incidence of major cardiac adverse events in the following year was 9.2 percent for the sirolimus stent and 14.1 percent for the paclitaxel stent.
But Nissen said the study had its flaws.
"First, this is an observational study. The reasons why physicians used one stent over another weren't factored in," he noted. "Some physicians might have a preference for one over the other."
More important, Nissen said, is that the numbers were driven by "soft" endpoints, relatively minor health woes, rather than by significant cardiac events that would be of most concern to patients. "If you read the table, you see that most of the really hard endpoints, such as myocardial infarction [heart attack], don't reach statistical significance," he said.
Finally, the average follow-up per patient was just 290 days, a relatively short period. "We've just heard about problems with these devices in the second and third year," Nissen said. "Something that is superior in the short run might not be superior in the long term."
The only way to determine which stent is best is a longer, large-scale study in which all factors are carefully controlled, Nissen said.
According to Nissen, drug-coated stents remain the device of choice for U.S. cardiologists, holding a 90 percent market share even though they cost substantially more than bare-metal stents. There has been an indication of a slight decline in their use recently, however. In Europe, drug-coated stents have about 50 percent of the market, Nissen noted.
For his part, Strauss said he is "trying to come to a decision" about whether the differences between the two stents seen in the study are "clinically relevant." He believes the difference -- which favors the Cypher stent -- may be relevant, based not only on this study but on previous trials that gave a slight edge to the sirolimus-coated stent.
The difference is most important in smaller arteries, Strauss said, where even a slight blockage can have an important effect, Strauss said. "The difference is enough for me now in smaller vessels to have me shift to the Cypher stent," he said.
However, in his editorial, Strauss added that "there still is need for corroborative support from prospective, randomized multi-center studies or other large single-center experiences" before one stent can be definitively preferred over the other.
For his part, Smith said it was impressive that the study included patients with different problems, such as blockages of smaller blood vessels. But he added that "it's hard to draw conclusions from a registry like this. It certainly is hypothesis-generating, but until a randomized clinical trial is done it will remain in the realm of interesting observations."
Smith is chairman of the American Heart Association/American College of Cardiology Task Force on Practice Guidelines, which may ultimately issue a judgment on which stent is best.
Find out more about drug-eluting stents from the U.S. Food and Drug Administration.