New developments in parenteral anticoagulation for arterial and venous thromboembolism.

The efficacy and safety of heparin and low-molecular-weight heparins (LMWHs) are well documented in venous and arterial thromboembolism. Several drawbacks of heparins have inspired the development of newer parenteral anticoagulants for specific indications, including heparin-induced thrombocytopenia (HIT) and percutaneous coronary interventions (PCI). The direct thrombin inhibitors recombinant hirudin and argatroban are now established alternatives for HIT patients, and bivalirudin is one of the most used anticoagulants in PCI. The pentasaccharide fondaparinux is an alternative for LMWH for thromboprophylaxis in various clinical settings and for patients with an acute coronary syndrome (ACS) not scheduled for PCI. In Europe, it was recently approved for treatment of superficial vein thrombosis. Further development of new parenteral anticoagulants is slow and the emphasis has shifted towards development of new oral anticoagulants and antiplatelet drugs. Still, promising new anticoagulants, some targeting less conventional targets in the coagulation system, have been developed and will undergo further clinical evaluation.