Clinical potential of antithrombotic drugs in coronary syndromes.

Thrombosis is responsible for most of the acute manifestations of coronary artery disease, including unstable angina and non-Q-wave myocardial infarction. Antithrombotic therapy with antiplatelet agents and anticoagulants plays a major role in decreasing the risk of ischemic events in such patients. As thrombin generation plays a key role in the pathogenesis of thrombosis, recent studies have focused on thrombin inhibition in the management of acute ischemia. Heparin is the most widely used anticoagulant in the acute phase. Heparin given in therapeutic doses intravenously has been shown to be more effective than aspirin in decreasing the risk of death or myocardial infarction in patients with unstable angina. Low-molecular-weight heparin (LMWH) has improved pharmacologic and pharmacokinetic properties over standard heparin and this may provide greater efficacy and safety. LMWH may be given at fixed subcutaneous dose without monitoring and, therefore, is of greater clinical utility and is more cost-effective than standard heparin. Several LMWHs have been evaluated in the management of acute coronary syndromes and have shown equivalent or improved efficacy compared with standard heparin. As heparin in combination with aspirin is now the treatment of choice in acute unstable coronary syndromes, LMWH could potentially improve the outcome in such patients.