Tuesday, April 29, 2008

New drug-eluting stents not any safer than traditional stents, according to a new study
By Kelly Winget, DCRI Communications

A recent study led by DCRI researchers found that a new type of drug-eluting stent (DES) was not any more effective at reducing short- and long-term artery inflammation and serious blood clots in patients than the stents already approved and used routinely by cardiologists.

The study results were published in the April 22 issue of the Journal of the American College of Cardiology. A similar paper on the design of the study, led by the DCRI's Tracy Wang, was published in the May 2007 issue of American Heart Journal.

The study, led by Mitchell Krucoff, MD, FACC, compared a commonly-used DES that delivers drugs via a polymer coating with a novel stent that delivers drugs via laser cut reservoirs within the stent, where the polymer coating dissolves entirely, leaving just the bare stent.

Stents are implanted in coronary arteries during a percutaneous coronary intervention (PCI) to widen the arteries by pushing plaque to the artery wall, which improves blood flow to the heart. Drug-eluting stents provide targeted delivery of drugs to reduce restenosis, or re-closing of the arteries. While rare, some patients who receive drug-coated stents are more likely to have fatal blood clots than patients who receive bare stents. DCRI researchers hypothesized that long-term exposure to the traditional polymer coating might factor into the increased risk for fatal blood clots.

The COSTAR (Cobalt Chromium Stent with Antiproliferative for Restenosis) II study is the first pivotal study to compare the CoStar stent, which has laser-cut reservoirs instead of a durable polymer coating, to the already approved Taxus DES in a noninferiority study.

Researchers enrolled 1,700 patients in the trial, and patients were randomly assigned to either receive the CoStar stent or the Taxus stent. A total of 989 patients received CoStar stents and 686 received Taxus stents.

The study found that 11 percent of the CoStar patients had a major adverse cardiac event within eight months of receiving the stent, compared to 6.9 percent of patients who received the Taxus stents. The patients who received the CoStar stents were also more likely to experience a heart attack within eight months of the stent implant, with 3.4 percent of the patients with CoStar having heart attacks compared to 2.4 percent of the patients with Taxus.

The study found that the CoStar DES was not noninferior to the routinely used Taxus DES. Researchers noted that the main benefit for the Taxus stents was that fewer patients required total vessel revascularization. Follow-up on both sets of patients 9 months after the stents were implanted showed no difference in the rate of death, heart attack or serious blood clots.