Therapy and secondary prevention of venous thromboembolism with vitamin K antagonists

Abstract

Oral anticoagulation with vitamin-K-antagonists is very effective in secondary prevention of venous thromboembolism. In Germany, most commonly Phenprocoumon is used, while most of the evidence-based data are available for Warfarin. The initial treatment of acute venous thromboembolism requires immediate anticoagulation with heparin and a subsequent overlapping treatment with oral anticoagulants. During this phase, anticoagulation may be unstable with increased risk for bleeding. An INR target range between 2 and 3 provides effective protection with minimal risk for major bleeding. The individual risk for bleeding may be estimated by a clinical score. Six months of oral anticoagulation is the standard duration for a first episode of venous thromboembolism, while recurrencies are treated for at least one to two years. The duration may be tailored to the individual patient according to underlying risk factors for recurrencies and for bleeding. Because of a plethora of practical problems and the narrow therapeutic window, there is a need for new antithrombotic agents. These may allow a longer duration of secondary prevention with improved protection against recurrencies without sacrificing safety.