What is the best anticoagulant therapy during primary percutaneous coronary intervention for acute myocardial infarction?

Both ST-segment elevation myocardial infarction and percutaneous coronary intervention (PCI) are associated with a highly prothrombotic state, and thrombin plays a critical role during occlusive clot generation and subsequent occurrence of an ischemic event. Therefore, a strategy of anticoagulation plus dual antiplatelet therapy has been regarded as de facto standard therapy during primary PCI (pPCI). Recently, there has been great controversy surrounding the role of bivalirudin versus unfractionated heparin in pPCI. Earlier, the results of the HORIZONS-AMI trial, particularly those regarding the long-lasting mortality benefit, provided a strong rationale for recommending bivalirudin therapy in pPCI. However, the mortality benefit of bivalirudin observed in HORIZONS-AMI has not been repeated in more contemporary studies or demonstrated in recent meta-analyses. The current report will provide a concise review of the controversy surrounding the optimal anticoagulant therapy for pPCI. Recent evidence suggests that unfractionated heparin deserves strong reconsideration despite the reports of pharmacologic weaknesses, particularly when used with a strategy of selective glycoprotein IIb/IIIa therapy, and it appears that a strategy of bivalirudin therapy in pPCI should be reserved for patients at high bleeding risk.