Use of Drug-Releasing Stents Associated With Decrease in Repeat Procedures to Unblock Coronary Arteries
CHICAGO, June 24, 2008â€”The widespread adoption of the use of drug-releasing coronary artery stents into routine practice is associated with a decrease in the need for repeat procedures to unblock coronary arteries and also do not appear to increase the risk of death, compared to bare-metal stents, according to a study in the June 25 issue of JAMA.
â€œThere has been a growing concern about the possibility of an increased risk of stent thrombosis (ST; formation of a clot in a blood vessel) associated with the use of drug-eluting [releasing] stents compared with bare-metal stents. Although a relatively rare event, stent thrombosis is associated with a high risk of myocardial infarction (MI; heart attack) and death and any suggestion of possible excess risk has justifiably been the focus of intense investigation,â€ the authors write. Despite several recent studies, there remains uncertainty about the trade-offs between the safety and effectiveness of drug-eluting stents.
David J. Malenka, M.D., of Dartmouth-Hitchcock Medical Center, Lebanon, N.H., and colleagues performed a study to compare the rates of revascularization (repeat procedure to unblock a coronary artery), heart attack and survival, before and after the availability of drug-eluting stents. The study included 38,917 Medicare patients who underwent non-emergency coronary stenting from October 2002 through March 2003 when only bare-metal stents were available and 28,086 similar patients who underwent coronary stenting from September through December 2003, when 61.5 percent of patients received a drug-eluting stent and 38.5 percent received a bare-metal stent. Follow-up data were available through December 2005.
During the 2 years of observation, 22.8 percent of patients in the bare-metal stent era group underwent a repeat revascularization (20.0 percent, percutaneous coronary intervention [PCI; procedures such as balloon angioplasty or stent placement used to open narrowed coronary arteries]; 4.2 percent, coronary artery bypass graft [CABG]). In the drug-eluting stent era group, 19.0 percent of patients underwent a repeat revascularization (17.1 percent PCI; 2.7 percent CABG). The risk of repeat revascularization decreased by approximately 18 percent in the drug-eluting stent era compared with the bare-metal stent era.
There was no difference in unadjusted mortality risks at 2 years (8.4 percent vs. 8.4 percent), but a small decrease in ST-elevation myocardial infarction (STEMI; a certain pattern on an electrocardiogram following a heart attack) existed (2.4 percent vs. 2.0 percent). The adjusted risk of death or STEMI at 2 years was similar.
â€œAlthough such an analysis will not answer the question of what is the true rate of stent thrombosis with drug-eluting stent vs. the rate with bare-metal stent, it does address the important question of whether, on-average, the population of stented patients is being helped or hurt by the widespread use of this technology,â€ the authors write.
â€œAlthough other data may suggest some incremental risk of
stent thrombosis with the use of drug-eluting stents, we can detect
no adverse consequence to the health of the population. We
speculate that whatever the increased risk of stent thrombosis
associated with drug-eluting stent use is, it is more than offset
by a decrease in the risk of developing restenosis [renarrowing of
a coronary artery after angioplasty] and the attendant risk of a
procedure to treat that restenosis.â€
(JAMA. 2008;299:2868-2876. Available pre-embargo to the media at www.jamamedia.org)
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Posted: June 2008