Antithrombotic therapy in ST-segment elevation myocardial infarction

Anticoagulation is an integral part of both fibrinolytic therapy and percutaneous intervention (PCI) in the reperfusion treatment of ST-segment elevation AMI (STEMI).

This article reviews the choices of adjunctive anticoagulation regimens. Readers will appreciate the complexities of anticoagulation and the variable risk of clotting with ischemic/thrombotic complications versus that of bleeding. Antiplatelet therapy with aspirin and clopidogrel is recommended with fibrinolysis and PCI. Newer P2Y(12) inhibitors such as prasugrel and ticagrelor have been shown to reduce cardiovascular death, myocardial infarction (MI), stroke and stent thrombosis, as compared with clopidogrel. Ticagrelor has also been shown to reduce mortality. Glycoprotein IIb/IIIa inhibitors, by blocking the final pathway of platelet clumping with each other through bridging with fibrinogen, have the ability to disaggregate platelets, hence the potential for reducing thrombotic complications as well as increasing bleeding in patients undergoing PCI bleeding risks. Enoxaparin reduces death and MI compared with unfractionated heparin (UFH) with fibrinolytic therapy. There was a trend for a reduction in death, MI procedural failure or non-coronary artery bypass grafting (CABG) major bleeding compared with UFH in primary PCI. In primary PCI, bivalirudin has the advantage over UFH of inhibiting clot bound thrombin and reduces bleeding and mortality compared with the use of UFH plus glycoprotein IIb/IIIa inhibitors. Combinations of P2Y(12) antagonists and bivalirudin need to be tested to optimize the balance between efficacy and bleeding.

This field is rapidly evolving with multiple appropriate approaches.