CHICAGO, March 29 A large randomized trial will shed lighton the ideal combination of medications for preventing unwanted blood clottingduring and shortly after percutaneous coronary intervention (PCI).Specifically, study investigators expect to determine whether bivalirudin, adirect inhibitor of the clotting protein thrombin, is better thanunfractionated heparin, an indirect thrombin inhibitor, in patients who havealso been treated with high-dose clopidogrel.
The Intracoronary Stenting and Antithrombotic Regimen: Rapid Early Actionfor Coronary Treatment 3 (ISAR-REACT 3) study is being presented today in aLate-Breaking Clinical Trials session at the SCAI Annual Scientific Sessionsin Partnership with ACC i2 Summit (SCAI-ACCi2) in Chicago. SCAI-ACCi2 is ascientific meeting for practicing cardiovascular interventionalists sponsoredby the Society for Cardiovascular Angiography and Interventions (SCAI) inpartnership with the American College of Cardiology (ACC).
Bivalirudin has outperformed unfractionated heparin in some previousstudies of PCI, but it's not clear how the two anti-clotting medicationsmeasure up when used in combination with what has become standard protocol inthe cardiac catheterization laboratory: preloading with a 600-mg dose ofclopidogrel, a medication that prevents clotting by inhibiting platelets.
"The distinguishing feature of our study is that a double-blind comparisonof the two different anti-thrombotic regimens was performed against a backdropof optimal oral anti-platelet loading therapy," said Adnan Kastrati, MD, aprofessor of cardiology and head of the catheterization laboratory atDeutsches Herzzentrum and Technical University, Munich, Germany. "Wehypothesized that in patients who were optimally pre-treated with clopidogrel,bivalirudin would continue to prove superior to unfractionated heparin, atleast in terms of safety -- by reducing bleeding side effects."
Bivalirudin has several potential advantages over unfractionated heparin:It does not rely on antithrombin to achieve its effects, it has a morepredictable dose-response pattern (and, therefore, does not require routineblood test monitoring) and it has a short plasma half-life, which is importantif a patient develops a bleeding problem.
For the study, Dr. Kastrati and his fellow ISAR-REACT 3 investigatorsrecruited 4,570 low-to-intermediate-risk patients who were undergoing PCI forreasons other than heart attack, randomly assigning them to receive eitherunfractionated heparin or bivalirudin during the procedure. All patientsreceived 600 mg of clopidogrel at least two hours before PCI, and all patientscontinued to take 75 mg of clopidogrel for at least one month after balloonangioplasty or implantation of bare-metal stents, and for at least six monthsafter implantation of drug-eluting stents. Patients continued to take aspirinindefinitely.
The study will determine whether use of bivalirudin influences rates ofbleeding during the initial hospitalization or the 30-day combined rates ofdeath, heart attack or urgent procedure to reopen the treated artery.
"This population under study is important, as it reflects the predominantgroup undergoing PCI, perhaps up to 70 percent," said Dr. Kastrati. "Ourresults may clarify the paradigm for peri-procedural adjunctive therapy inthis important group."
Dr. Kastrati will present the results of the "Intracoronary Stenting andAntithrombotic: Regimen Rapid Early Action for Coronary Treatment 3"(ISAR-REACT 3) study on Saturday, March 29 at 8:00 a.m. CDT in the GrandBallroom, S100.
Headquartered in Washington, DC, the Society for CardiovascularAngiography and Interventions is a 4,000-member professional organizationrepresenting invasive and interventional cardiologists in over 60 nations.SCAI's mission is to promote excellence in invasive and interventionalcardiovasc