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The study is being reported today in a Late-Breaking Clinical Trialssession at the SCAI Annual Scientific Sessions in Partnership with ACC i2Summit (SCAI-ACCi2) in Chicago. SCAI-ACCi2 is a scientific meeting forpracticing cardiovascular interventionalists sponsored by the Society forCardiovascular Angiography and Interventions (SCAI) in partnership with theAmerican College of Cardiology (ACC). This study is also being simultaneouslypublished online in JAMA: Journal of the American Medical Association.
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"These findings may provide a robust scientific rationale for high-dosetirofiban as an alternative to abciximab in patients with STEMI," said MarcoValgimigli, MD, PhD, a cardiologist at the Cardiovascular Institute, AziendaOpedaliera Universitaria di Ferrara, Ferrara, Italy. "In addition, at mid-termfollow-up our study did not confirm some of the safety concerns over the useof drug-eluting stents in patients with myocardial infarction. These findingsare very reassuring, though we need long-term follow-up to rule out thepossibility of late adverse events."
Drug-eluting stents -- which not only prop open the coronary arteries butslowly release medication that prevents re-narrowing of the arteries with scartissue, or restenosis -- are widely used when PCI is performed for stablecoronary artery disease. But many cardiologists use bare-metal stents whentreating patients with heart attack because studies have reported conflictingresults on the benefits of drug-eluting stents in this group of patients andhave raised concerns over the risk of blood clotting inside the stent, orstent thrombosis. The new study has certain design advantages over previousstudies, specifically its size and an enrollment and follow-up protocol thatmore closely reflects everyday clinical practice.
As for tirofiban and abciximab, both are in a class of medications knownas glycoprotein 2b/3a inhibitors and prevent blood clotting by blockinghyperactivation of platelets. Tirofiban is an attractive alternative forseveral reasons: It is shorter-acting and is cleared from the body morereadily than abciximab, it is less likely to cause a dangerous drop in thenumber of platelets in the blood, and it is far less expensive. However,previous studies have been too small or have used too low a dose of tirofibanto reach a definitive conclusion about which medication is better, Dr.Valgimigli said.
The new study, which involved 16 medical centers, enrolled 745 patientswho were set to undergo PCI for STEMI. Patients were randomly assigned to aninfusion of abciximab or high-dose tirofiban (25 microgram/kg) and, in asecond round of randomization, to treatment with either uncoated orsirolimus-eluting stents.
To judge the effectiveness of tirofiban and abciximab, researchersexamined electrocardiograms -- 722 of which were interpretable -- to determinethe proportion of patients with at least a 50 percent return of the elevated"ST-segment" to its normal baseline. The results were equivalent in the twogroups (83.6 percent in the abciximab group vs. 85.3 percent in the tirofibangroup). In addition, there was no significant difference in the rate of majoradverse cardiac events (MACE) -- a combination of death, repeat heart attack,and repeat procedure to open the treated coronary artery -- in the two groups:4.8 percent vs. 4.5 percent, respectively, at 30 days and 12.3 percent vs. 9.9percent, respectively, at e
