Anticoagulant effect of dabigatran, rivaroxaban or apixaban treatment on different laboratory hemostasis tests in patients with atrial fibrillation

The clinical use of new oral anticoagulants (NOA) – dabigatran, rivaroxaban and apixaban – is greatly expanding and dosing their effect may be required in specific situations. Aim of the study was to determine their effect on different hemostasis tests in patients with atrial fibrillation. Citrated blood was taken just before a dose (TTrough) and 3 hrs after the administration (Tmax) (at TTrough: 110 – dabigatran, 57 – rivaroxaban and 30 – apixaban patients; at Tmax, 62, 18 and 18 patients). PT, aPTT, PC, PS and aPCR (IL, USA), dTT (Siemens, USA), Hemoclot technique and Biophen DXaI test (Hyphen Biomed, France) and Light Transmission platelet Aggregometry (LTA, APACT4004, and LabiTec, Germany) were performed. At Tmax, PT, aPTT were significantly prolonged (dabigatran: +23%, +26%, respectively [+42% for dTT]; rivaroxaban: +43% and +21% respectively; apixaban: +14% and +6% respectively; for all, p<0.00). No change was observed for the other clotting test and LTA. At Tmax, dabigatran and rivaroxaban plasma levels were significantly increased (+122% and +116%, respectively; p<0.000). Significant relationships between drug plasma concentration and PT and aPTT and dTT values were observed (at least, p=0.01). The anticoagulant effect of dabigatran, rivaroxaban and apixaban influences only clotting tests (PT, aPTT and dTT), whereas the inhibitory system and platelet function were not affected. The interpretation of the laboratory test might be translated into clinical decisions with efficacy and safety.