Nach den aktuellen Leitlinien kardiologischer und neurologischer Fachgesellschaften werden die neuen oralen Antikoagulanzien gegenüber Vitamin-K-Antagonisten bevorzugt empfohlen. Die aktuellen Registerdaten bestätigen die in den Zulassungsstudien gewonnenen Daten einer gegenüber Vitamin-K-Antagonisten höheren Sicherheit und mindestens vergleichbaren Effektivität. Differenzialtherapeutische Vergleiche zwischen den 4 NOAKs sind bei unterschiedlichen Patientenkollektiven in den Zulassungsstudien nur bedingt zulässig. Differenzialtherapeutisch kommen für die Verordnung der NOAKs Aspekte, wie die renale Elimination bei eingeschränkter Nierenfunktion, Einmal- oder Zweimalgabe, Verfügbarkeit eines Antidots, vorbestehende gastrointestinale Blutungsanamnese und persönliche Erfahrungswerte in Betracht.
According to recommendations in the current guidelines of the professional societies for cardiology and neurology, the new oral anticoagulants are to be preferred over vitamin K antagonists. In a metaanalysis of large phase III trials the new oral anticoagulants were found to reduce the risks for stroke and systemic embolism by 19% in comparison with vitamin K antagonists (p < 0,0001). Furthermore, the new oral anticoagulants were altogether shown to exhibit a lower overall mortality (p = 0,0003) as well as a lower incidence of intracranial bleeding (p < 0,0001) with, however, a higher incidence of gastrointestinal bleeding (p = 0,04). The mechanism responsible for the increased rates of gastrointestinal bleeding for dabigatran and the factor Xa inhibitors is not completely clear as yet. Dabigatran and, to a lesser extent, the factor Xa inhibitors are partially excreted through the intestine by a P-glycoprotein transport system so that, possibly an elevated concentration of the active principles is present in the intestinal mucous membranes. Dabigatran exhibits a low bioavailability (7,2 %) and is activated directly in the gastrointestinal tract, thus a prolonged contact time of the active components in the intestine can lead to a locally slightly increased tendency for bleeding. In contrast, warfarin with a higher bioavailability is more completely absorbed and the not absorbed portions are not active.
Current register data confirm the findings obtained in the approval trials concerning a higher safety and an at least equivalent efficacy as compared with vitamin K antagonists. Differential therapeutic comparisons of four new oral anticoagulants in differing patient collectives in the appoval trials are of only limited relevance. For the prescription of the new oral anticoagulants, aspects such as renal elimination in cases of renal insufficiency, once or twice daily administration, availability of an antidote, preexisting history of gastrointestinal bleeding and personal experience should be considered from the differential therapeutic point of view.
Key words
Anticoagulation - new oral anticoagulants - atrial fibrillation - stroke - embolism - gastrointestinal bleeding - register data
