Drug-Eluting Stent Found to Have Comparable Safety, Benefits to Bare-Metal Stent in Angioplasty for AMI
- Tue, 3/16/10 - 11:05am
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5-year data from the PASSION trial found no statistically significant difference between a paclitaxel-eluting stent and a bare-metal stent
ACC 2010, Atlanta, Georgia – In the first randomized, controlled trial to report 5-year data on the safety and benefits of drug-eluting stents compared with bare-metal stents in acute myocardial infarction (AMI), researchers found no statistically significant difference in either safety or efficacy between the two groups, according to research presented today at the American College of Cardiology’s 59th annual scientific session. ACC.10 is the premier cardiovascular medical meeting, bringing together cardiologists and cardiovascular specialists to further advances in cardiovascular medicine.
The 5-year findings from the PASSION trial contrasted with the researchers’ hypothesis that the paclitaxel-eluting stent would perform significantly better for cardiac death, recurrent heart attack, and target lesion revascularization. The results also failed to show a statistically significant difference between the two stent types in preventing very late stent thrombosis (a blood clot that forms on the stent at least 1 year after the procedure), which has been a primary concern of drug-eluting stent use.
The trial dated from between March 2003 and December 2004 and randomized 619 patients with acute heart attack to receive either the Taxus Express2 (a paclitaxel-eluting stent) or the Express2 or Liberté (bare-metal stents). All stents were manufactured by Boston Scientific.
Specifically, the prospective, single-blind study did not show a statistically significant difference between the paclitaxel-eluting stent and the bare-metal stent for the primary composite endpoint of cardiac death, recurrent heart attack, and target lesion revascularization, at 18.3% and 22.0%, respectively. The researchers also did not find a statistically significant difference between the two stent groups for any of the major cardiac events when examined individually.
Furthermore, despite a two-fold increase in the occurrence of definite stent thrombosis (a blood clot that has been confirmed through angiographic evidence) in the paclitaxel-eluting stent group compared with the bare-metal stent group – at 3.6% and 1.7%, respectively – the occurrence of both definite and probable stent thrombosis, (which includes suspected clots that have not been confirmed and which more closely resembles a real-world patient population) was comparable, at 3.9% and 3.4%, respectively.
― I think we can conclude from the trial that the use of drug-eluting stents in primary angioplasty is safe through several years after implantation, said Maarten Vink, MD, of the Onze Lieve Vrouwe Gasthuis Hospital in Amsterdam, The Netherlands, one of the study’s researchers. ― Compared to bare-metal stents, we did not find a difference in the occurrence of the primary composite endpoint of major adverse cardiac events. There is a potential risk of very late stent thrombosis, however, that appeared in our study, so we must carefully weigh the benefits and drawbacks of using drug-eluting stents for AMI.
The 5-year data follow in line with both PASSION’s 1-year data and 2-year data – which also found no statistically significant safety or benefit differences between the two stents – but Vink notes that the 5-year results are especially important to examine in light of data in clinical registries that associate drug-eluting stent use with very late stent thrombosis.
While Vink acknowledges that the study provides valuable insight into the debate surrounding this issue, he cautions that because the PASSION trial is the first large, randomized, controlled study to report 5-year data, its findings cannot provide definitive answers on the use of drug-eluting stents in acute heart attack.
―Right now, the clinical guidelines are not conclusive concerning the use of drug-eluting stents in angioplasty for acute heart attack, as the European Society of Cardiology does not define if they should be used, while the American College of Cardiology provides an indication for them, said Vink. ―Because the guidelines are not uniform, I think their use will remain an issue—one without a definite answer—until we have data from more large, randomized, long-term studies.
The study was funded by the Department of Interventional Cardiology at the Onze Lieve Vrouwe Gasthuis Hospital. Dr. Vink has no personal disclosures.
