[New medical anticoagulants]

The limitations of conventional treatment using nonfractionated heparin have stimulated research in new anticoagulants which act at different levels of the coagulation pathways. New natural or synthetic compounds have been developed to improve current treatments. Included among these compounds are indirect thrombin inhibitors such as dermatan sulfate, heparanoids and low-molecular weight heparin. Low-molecular weight heparins are particularly interesting for venous thromboembolism and acute coronary syndromes. Several studies have demonstrated their efficacy in unstable angina and myocardial infarction without Q wave. In comparison with nonfractionated heparin, administration of enoxaparin offers a supplementary benefit. Indirect thrombin inhibitors such as hirudin and its derivatives are also being evaluated and have shown a certain efficacy in the prevention of postoperative deep vein thrombosis although no superior effect compared with nonfractionated heparin has been demonstrated in thrombotic coronary disease. Finally, indirect anti-Xa agents and physiological coagulation inhibitors are also being assessed.