[Prophylaxis of postoperative thromboembolism. New alternatives to low-molecular-weight heparin]

For somewhat more than a decade low molecular weight heparins have dominated in the pharmacological prevention of postoperative venous thromboembolism. At present there are some new methods of potential interest both as prophylactic substances but also to better understand the pathophysiology of deep vein thrombosis. These are inhibition of factor VII a/tissue factor complex (NAP, Nematode Anticoagulant Protein), inhibition of activated factor X (the synthetic pentasaccharide fondaparinux) and thrombin inhibition (melagatran and its oral prodrug ximelagatran). They have been shown to be effective in high risk orthopaedic surgery. They have to show their place in the prophylactic arsenal in comparison with low molecular weight heparins (effect, safety, mode of administration, cost-effectiveness).