In the first published trial of its kind, a multi-center clinical study has shown that drug-eluting stents outperform the current "gold standard" radiation treatment in managing coronary restenosis and in preventing further clogging of coronary arteries.
Results of the TAXUS Express stent trial led by Columbia University Medical Center researchers at NewYork-Presbyterian Hospital/Columbia were published in the March 15 issue of the Journal of the American Medical Association. The study results were also presented March 12 at the American College of Cardiology's annual scientific meeting in Atlanta.
The trial studied 396 patients whose bare metal stents had become clogged with scar tissue, a common complication called restenosis. About half of the patients received paclitaxel-eluting stents, while the other half received vascular brachytherapy, which delivers radiation to the inside of the artery via a catheter. Vascular brachytherapy is currently the only FDA-approved treatment for restenosis after bare metal stent implantation. Paclitaxel is a drug that inhibits cell migration and prevents restenosis. The TAXUS Express stent is made by Boston Scientific Corp.
After 9 months, the trial showed that the paclitaxel-eluting stents reduced by 40 percent the number of patients needing additional procedures to clear the artery, compared to vascular brachytherapy. Angiographic measurements in both groups showed that patients who had drug-eluting stents experienced less than half as much restenosis (14.5 percent) as those who had brachytherapy (31.2 percent).
The trial also showed that the benefits of paclitaxel-stenting were achieved without compromising safety. Paclitaxel stents reduced major cardiac events from 20.1 percent in the brachytherapy group to 11.5 percent. The two treatments had similar rates of cardiac death or myocardial infarction (5.2 percent for brachytherapy and 3.7 percent for stenting) and thrombosis in the stented artery (2.6 percent for brachytherapy and 1.6 percent for stenting)
"The results are what everyone was hoping for. Drug-eluting stents should now be considered the standard of care for most patients with restenosis of previously implanted bare metal stents, and radiation treatment should be abandoned," said Gregg Stone, M.D., professor of medicine at Columbia University College of Physicians and Surgeons, director of cardiovascular research and education at the Center for Interventional Vascular Therapy at NewYork-Presbyterian Hospital/Columbia, and vice chairman of the Cardiovascular Research Foundation.
Other trials in the past few years have shown drug-eluting stents to be superior to bare metal stents in preventing restenosis, when used for initial stent placement inside a coronary artery. The TAXUS-V ISR trial was designed to determine the safety and efficacy of drug-eluting stents as an alternative to vascular brachytherapy in treating restenosis resulting from previously implanted bare metal stents. Vascular brachytherapy is effective in some patients, but the procedure is costly and complex, and years later, can cause complications, such as thrombosis and more restenosis.
Although the majority of first-time stents used in coronary arteries are now drug-eluting, bare metal stents continue to be used for conditions where studies on drug-eluting stents are still incomplete (e.g. acute myocardial infarction). Bare metal stents are also used in countries where the cost of drug-eluting stents is not covered and in select patients who can't tolerate an extended course of dual anti-platelet therapy.
"The single most common reason for referral to bypass surgery after bare metal stent implantation is still recurrent restenosis," said Dr. Stone. "Identification of drug-eluting stents as the optimal therapy for bare metal restenosis should significantly reduce the need for surgery in many thousands of patients."