Abstract: Acute coronary syndrome (ACS) is a clinical syndrome caused by acute cardiac ischemia,including unstable angina (UA) ,non-ST-segment elevation myocardial infarction (NSTEMI) and ST-segment elevation myocardial infarction (STEMI).Currently antiplatelet and antithrombin therapies become the two important components of the antithrombotic treatment of patients with ACS.The advent of potent antiplatelet and antithrombin agents has resulted in significant improvement in reducing ischemic events in patients with ACS. However,the combination of antiplatelet and antithrombotic therapy during the PCI periprocedural period,has led to an increase in the risk of bleeding. More importantly,such complications have been reported to be associated with an increased risks of mortality,myocardial infarction,and stroke. Possible mechanisms include bleeding-induced imbalance of the coagulant/anticoagulant, adverse effects induced by transfusion, and cessation of antithrombotic/anticoagulant therapy. So the balance between antithrombotic effect and risk of bleeding may further improve clinical outcomes of patients with ACS. In this article we present an overview on clinical trials evaluating the different aspects of antithrombotic therapy in patients undergoing PCI and discuss the emerging role of these agents in the contemporary era of early invasive coronary intervention.

Key words: Acute coronary syndrome, Percutaneous coronary intervention, Antithrombotic therapy