New anticoagulant strategies in ST-elevation myocardial infarction treated with fibrinolytic therapy

Anticoagulant therapy plays a key role in pharmacological reperfusion therapy for acute ST segment elevation myocardial infarction (STEMI). Until recently, the established role of unfractionated heparin (UFH) was unquestioned, but large trials with new agents including factor Xa inhibitors, direct thrombin inhibitors, and in particular, low molecular weight heparins (LMWHs), have shown potential advantages compared with UFH. This paper reviews the evidence base for the newer anticoagulants, with a focus on LMWH including the Enoxaparin and Thrombolysis Reperfusion for Acute Myocardial Infarction Treatment - Thrombolysis in Myocardial Infarction (EXTRACT TIMD-25 study, which found that enoxaparin when appropriately adjusted for weight, age and renal function, provided superior net clinical benefit (balancing efficacy and safety) compared with UFH. In addition, new data from higher risk subgroups (the elderly, those with renal dysfunction or undergoing early coronary intervention) and the efficacy and safety of using concurrent clopidogrel are discussed to illustrate how these data may be integrated into contemporary practice.