Persistence of the prothrombotic state after acute coronary syndromes: implications for treatment

Background and Purpose Acute coronary syndromes (unstable angina and acute myocardial infarction) are generally caused by thrombosis over a disrupted atherosclerotic plaque. During the acute phase, antithrombotic therapy (including aspirin and heparin) has been shown to reduce the risk of death or myocardial infarction (MI). The purpose of this review is to examine the high-risk period for clinical thrombotic events that extends for several weeks after presentation and to review the treatments aimed at reducing these events. Results More than half of clinical events reported during the first month occur after the first 3 to 5 days that comprise the standard in-hospital treatment period. Several different antithrombotic approaches have been tested, including longer duration of antiplatelet therapy, anticoagulant treatment, and oral glycoprotein (GP) IIb/IIIa inhibitors. Aspirin is effective at reducing risk, and clopidogrel provides additional benefit, as does dalteparin for at least the first month. Warfarin in addition to aspirin, while generally disappointing, has not been adequately tested at higher doses. Oral GP IIb/IIIa inhibitors cause a paradoxic increased risk of death for unclear reasons. Conclusion Further reduction of risk during the weeks after presentation with acute coronary syndromes remains an important therapeutic goal. (Am Heart J 2002;143:205-16.)