First evidence: rivaroxaban and apixaban reduce thrombin-dependent platelet aggregation.

Rivaroxaban and apixaban are direct oral anticoagulants whose target specificity is to activate factor X (FXa). It is still not fully understood how xabans impact platelet function. This single-center observational study aimed to assess in vitro platelet function in patients with atrial fibrillation receiving rivaroxaban or apixaban. It examined quantification of platelet aggregation assessed by light transmission aggregometry in thirty-four patients treated with apixaban or rivaroxaban. The thrombin-induced platelet aggregation was significantly lower 2 h after taking selected xabans compared to baseline value (69.55 ± 32.15% vs. 44.79 ± 34.97.9%; p < 0.0001). This effect was only observed in patients who received rivaroxaban or apixaban for more than 1 week. The thrombin-induced platelet aggregation is reduced in cardiovascular patients receiving rivaroxaban or apixaban. This reduction is likely to depend on the duration of the treatment. Duration of treatment should be considered in future studies focusing on DOACs and platelet aggregation.