Drug-Coated Stents Are Equal
Stents' Different Drug Coatings Don't Mean Different Effects
Jan 30, 2008 -- Two different drug coatings keep artery-opening stents from clogging. One works as well as the other, a new study shows.
Balloon angioplasty opens clogged arteries without the need for chest surgery. About 40% of the time, these arteries clog up again. If the artery is propped open with a stent -- a mesh tube -- the reclog rate is cut to about 20%. But if the stent is coated with drugs that prevent clogging, the reclog rate drops to about 10%.
Two different drugs are used to coat the so-called drug-eluting stents. Small studies to see which one works better have focused only on highly selected groups of patients but don't show what happens when the stents are used in the real world.
That's why Anders M. Galloe, MD, of Gentofte University Hospital in Copenhagen, Denmark, and colleagues simply looked at what happened to Danish patients who received drug-eluting stents from August 2004 to January 2006.
In this double-blind study, doctors randomly installed paclitaxel-coated stents (the Taxus stent from Boston Scientific) in 1,033 patients and sirolimus-coated stents (the Cypher stent from Cordis/Johnson & Johnson) in 1,065 patients.
About 11% of the patients who got the paclitaxel-coated stents and about 9% of the patients who got the sirolimus-coated stents died of heart disease, had heart attacks, or needed a second procedure due to reclogging of the same blood vessel.
That difference was neither statistically significant nor clinically significant, Galloe and colleagues conclude.
A problem with drug-eluting stents is that the coating that keeps them from clogging sometimes allows dangerous blood clots to form in the stent. This relatively rare event was no more likely with one drug coating than with the other.
Galloe and colleagues note that there were far fewer bad outcomes than expected among study participants. This made the study far less powerful in detecting drug-coating differences than the researchers had hoped.
The study appears in the Jan. 30 issue of The Journal of the American Medical Association. Accompanying the report is an editorial by University of Kentucky cardiologists Debabrata Mukherjee, MD, and David J. Moliterno, MD.
The editorial notes that the study may not have been able to detect small differences between the two drug coatings. But Mukherjee and Moliterno note that it does show one thing: drug-coated stents are quite safe as used in the real world.
Two second-generation drug coatings for stents will soon become available. Mukherjee and Moliterno call for a registry that will record outcomes for all patients who receive drug-coated stents for any reason.