Effect of Prasugrel Versus Clopidogrel on Platelet Function After Bivalirudin Cessation

Early stent thrombosis has been noted with increased frequency in acute coronary syndrome (ACS) patients undergoing percutaneous coronary intervention (PCI) who are treated with bivalirudin and clopidogrel. The brief half life of bivalirudin acting in concert with the delayed action of clopidogrel likely exposes patients to thrombosis during a vulnerable period of reduced antiplatelet effect in the immediate post stenting period. Combination therapy with bivalirudin and prasugrel is conceptually attractive as the more rapid onset of action of prasugrel could potentially significantly diminish the vulnerable period, likely reducing the potential for acute stent thrombosis. The trials which have documented the efficacy of prasugrel as compared to clopidogrel have, in general, not reported on patients in whom bivalirudin was utilized. Currently, in the United States, bivalirudin is the most commonly used adjunctive agent used during PCI. Using light transmission aggregometry, this study will examine the inhibition of platelet aggregation in patients randomized to treatment with clopidogrel vs prasugrel during the vulnerable period following the discontinuation of bivalirudin therapy. The investigators anticipate that this study will document significant enhancement of inhibition of platelet aggregation in patients randomized to prasugrel treatment.