Evaluation of the Antithrombotic Effects of Rivaroxaban and Apixaban Using the Total Thrombus-Formation Analysis System®:In VitroandEx VivoStudies.
BACKGROUND
The usefulness of the Total Thrombus-Formation Analysis System®(T-TAS®) for monitoring the anticoagulant effects of non-vitamin K oral anticoagulants (NOACs) in clinical practice has been poorly addressed.


METHODS
NOACs (rivaroxaban and apixaban) were added to whole blood from healthy subjects in anin vitrostudy, and their effects on thrombus formation were evaluated by the T-TAS®. We also evaluated antithrombotic effects usingex vivosamples of whole blood from patients given rivaroxaban or apixaban at the respective trough and peak drug concentrations.


RESULTS
T-TAS®could determine anticoagulant effects in whole blood treated with rivaroxaban or apixabanin vitro. The increases in the anticoagulant effects of rivaroxaban and apixaban from the trough to peak concentrations in whole blood were successfully monitored by the T-TAS®usingex vivosamples. The antithrombotic effects of rivaroxaban and apixaban (in terms of factor Xa inhibition) at the peak were strongly linked to those at the trough.


CONCLUSIONS
T-TAS®could be a clinically useful tool for monitoring the anticoagulant effects of factor Xa inhibitors, and may represent an accurate quantitative analysis.
Department of Cardiology, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan; These authors contributed equally to this work.
Hidekazu
H
Sugihara
Department of Cardiology, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan; These authors contributed equally to this work.
Yoshiaki
Y
Idemoto
Department of Cardiology, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan.
Takashi
T
Kuwano
Department of Cardiology, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan.
Yoshihisa
Y
Nagata
Department of Cardiology, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan.
Joji
J
Morii
Department of Cardiology, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan.
Makoto
M
Sugihara
Department of Cardiology, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan.
Masahiro
M
Ogawa
Department of Cardiology, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan; Department of Molecular Cardiovascular Therapeutics, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan.
Shin-Ichiro
SI
Miura
Department of Cardiology, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan; Department of Molecular Cardiovascular Therapeutics, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan.
Keijiro
K
Saku
Antithrombotic capacities; Factor Xa inhibitors; Peak; Total Thrombus-Formation Analysis System; Trough