Abstract Number: PB0532
Meeting: ISTH 2020 Congress
Background: Direct oral anticoagulants (DOAC) are widely used for treatment of thromboembolism. Although DOACs are not routinely monitored, the measurement of its activity can be needed in multiple clinical scenarios. We have developed the modified diluted prothrombin time reagent (mdPT) based on prothrombin time (PT) assay for DOAC measurement as global assay.
Aims: The purpose of this study was to investigate the characteristics of mdPT reagent against DOAC concentration.
Methods: The patient samples including 275 apixaban, 257 edoxaban, and 243 rivaroxaban plasmas were employed in the comparative study between mdPT and DOAC concentration based on anti-Xa assay. For the normalization, mdPT results were shown as Ratio of Inhibited Thrombin Generation (RITG) = (a-b) / b x 100, where a = the clotting time of patient sample, b = the clotting time of normal sample. The samples were divided into three groups based on the 99 percentile confidence interval, group 1; lower discrepancy than the 99 percentile, group 2; within the 99 percentile, group 3; upper discrepancy group than the 99 percentile. Factor II, V, VII, X activity were compared in these three groups. The informed consent was obtained from all patients and the study was approved by the recognized medical ethics committees in all institutions.
Results: The correlation coefficients were 0.818, 0.914, and 0.814 in apixaban, edoxaban, and rivaroxaban, respectively. The factor II, V, VII, and X activity in group 3 was significantly lower than that in group 1 for apixaban and edoxaban. In rivaroxaban samples, a significant decrease was recognized in only factor V activity. Overall, the upper discrepancy in group 3 was derived from lower coagulation activity.
Conclusions: mdPT reagent reflected not only DOAC inhibition but also coagulation factor activity. mdPT may predict bleeding risk in patients treated with DOAC at a low level of coagulation activity.
To cite this abstract in AMA style:
Kumano O, Suzuki S, Yamazaki M, An Y, Yasaka M, Ieko M, the Japanese Study Group for the Effect Confirmation of Direct Oral Anticoagulants . New Formula of “Ratio of Inhibited Thrombin Generation” Based on Modified Diluted Prothrombin Time Reagent Predicts Bleeding Risk of Patients with Low Coagulation Activity in Direct Oral Anticoagulants Therapy [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/new-formula-of-ratio-of-inhibited-thrombin-generation-based-on-modified-diluted-prothrombin-time-reagent-predicts-bleeding-risk-of-patients-with-low-coagulation-activity-in-direct-or/. Accessed March 21, 2024.« Back to ISTH 2020 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/new-formula-of-ratio-of-inhibited-thrombin-generation-based-on-modified-diluted-prothrombin-time-reagent-predicts-bleeding-risk-of-patients-with-low-coagulation-activity-in-direct-or/