[New oral anticoagulants in atrial fibrillation]

Atrial fibrillation (AF) causes at least 20% of all ischemic strokes. In large randomized trials of primary and secondary stroke prevention, anticoagulation with vitamin K antagonists (VKA) protected much more efficiently than antiplatelet agents against stroke. Because of the problematic pharmacological properties of VKA only part of the AF patients are currently being treated with oral anticoagulants (OAK). The targeted development of specific oral inhibitors of the central coagulation factors thrombin and factor Xa allows reliable anticoagulation without regular coagulation monitoring. In the present review, pharmacological properties of the different agents are compared. Of the four large randomized phase 3 studies in AF (RELY, ROCKET-AF, ARISTOTLE, ENGAGE-AF) with the primary efficacy endpoint stroke and systemic embolism, the published data from the RELY trial indicate a superior efficacy of dabigatran etexilate (2 × 150 mg/day) and a lower risk of intracranial hemorrhage compared to warfarin. Favorable preliminary results have been demonstrated for the factor Xa inhibitor rivaroxaban. Apixaban was more efficacious than ASA and had a similar risk of hemorrhage in the AVERROES study. Thus, the available data suggest a favorable benefit-risk ratio for the new substances in addition to improved patient comfort. Currently unresolved issues relate to the verification of patient adherence by suitable coagulation tests and to the emergency coagulation diagnostics and therapy in acute ischemic or hemorrhagic strokes under the new OAC.