SUNDAY, March 12, 2006 (HealthDay News) -- If a bare-metal stent fails to keep an artery open, implanting a second, drug-coated stent is better than using radiation therapy, the only approved standard treatment, two new studies show.
Each study was financed by one of the companies that market coated stents -- Johnson & Johnson, whose stents are coated with sirolimus; and Boston Scientific, whose stents are coated with paclitaxel. The results could set the stage for a major head-to-head trial of the two contenders.
A stent is a flexible metal tube placed in an artery after a blockage is cleared away by the technique called balloon angioplasty. The original stents were all bare metal, but coated stents have become predominant since their introduction in the United States two years ago.
Even when a stent is in place, an artery can become blocked again. That happens about 20 percent of the time with bare-metal stents, and much less frequently with coated stents.
Each of the two studies compared a coated stent with vascular brachytherapy, which is radiation therapy and currently the only treatment approved by the U.S. Food and Drug Administration for what is formally called restenosis after a bare-metal stent has been implanted.
"The results were strikingly positive for sirolimus in terms of the primary endpoint," said Dr. David R. Holmes Jr., Scripps professor of cardiovascular medicine at the Mayo Clinic, who led that study. "They were not only statistically better, but clinically better."
That trial included 384 patients whose arteries began to close again after implant of a bare-metal stent. Only 10 percent of the 259 patients who got drug-coated stents suffered a major adverse cardiac event over the next nine months, compared to 19.2 percent of the 125 patients who got radiation therapy. There was also a significant difference in the rate of failure of the treated artery -- 21.6 percent in the radiation group, 12.4 percent in the sirolimus stent group.
Results of the paclitaxel-coated stent trial, which was led by Dr. Gregg Stone of Columbia University Medical Center in New York City, were similar. The rate of major adverse cardiac events among the 396 patients in the nine months following treatment was 43 percent lower for those who got coated stents than for those who got radiation therapy.
"These are two different studies done in different fashions, but the extent of benefit provided by each one over radiation seems to be similar," said Dr. David J. Moliterno, head of cardiology at the University of Kentucky, and co-author of an accompanying editorial in the March 15 issue of the Journal of the American Medical Association.
The research was released early to coincide with presentations on Sunday at the American College of Cardiology meeting, in Atlanta.
Both Holmes and Moliterno said coated stents will become the treatment of choice following failure of bare-metal stents. Aside from their increased effectiveness, the stents also are easier to administer than radiation therapy, which requires cooperation between cardiologists and radiation specialists, and is generally inconvenient, Holmes said.
And there is need for a better treatment, because many patients are still getting bare-metal stents after angioplasty, he said. Moliterno estimated that a quarter of the heart patients in the United States are getting bare-metal stents, and the percentage is higher in many countries.
As for which coated stent to use in such cases, "there doesn't seem to be a strong leaning for one stent over the other," Moliterno said.
There might be a need for a trial to test the effectiveness of each brand of coated stent for cases where a previous coated stent implant has failed, he added. The failure rate for coated stents is small, about half that for bare-metal stents, so the trial would have to be "quite large," Moliterno said.
Learn about stents from the U.S. Food and Drug Administration.