Dabigatran but not rivaroxaban or apixaban treatment decreases fibrinolytic resistance in patients with atrial fibrillation

- Dabigatran and rivaroxaban reduce fibrinolytic resistance in vitro
- No data are available on the effect of direct oral anticoagulants on fibrinolysis in vivo
- We show that dabigatran but not rivaroxaban or apixaban treatment reduces fibrinolytic resistance in patients with AF
- The profibrinolytic effect of dabigatran is due to its greater efficacy in reducing TAFI activation
- Enhancement of fibrinolysis may contribute to the antithrombotic activity of dabigatran.

IntroductionMost anticoagulants stimulate fibrinolysis in vitro through mechanisms dependent on and independent of thrombin activatable fibrinolysis inhibitor (TAFI). We evaluated the effect of dabigatran, rivaroxaban and apixaban treatment on plasma fibrinolysis in patients with non-valvular atrial fibrillation.Methods and resultsPatients treated with dabigatran etexilate (n = 22), rivaroxaban (n = 24) or apixaban (n = 22) were studied. Plasma was obtained before (trough) and 2 h after drug intake (peak). Fibrinolytic resistance of clots exposed to exogenous tissue plasminogen activator was significantly lower in peak than in trough samples and correlated with drug concentration only in dabigatran group. Moreover, fibrinolytic resistance at peak was lower in dabigatran than in rivaroxaban and apixaban groups. This difference disappeared if the TAFI pathway was inhibited. Thrombin generation and TAFI activation were markedly lower in peak than in trough samples in all three groups. However, TAFIa levels in trough and peak samples were significantly lower in dabigatran group than in rivaroxaban and apixaban groups. Circulating levels of prothrombin fragment F1 + 2 (reflecting in vivo thrombin generation) and plasmin-antiplasmin complex (reflecting plasmin generation) were not or barely influenced by drug levels in all groups.ConclusionsOur data suggest that dabigatran, contrary to rivaroxaban and apixaban, reduces fibrinolytic resistance by virtue of its greater impact on TAFI activation. The profibrinolytic effect of dabigatran may play a role locally, at sites of fibrin formation, by making the nascent thrombus more susceptible to plasminogen-dependent degradation.