Assessment of in vitro effects of direct thrombin inhibitors and activated factor X inhibitors through clot waveform analysis

Masatoshi Wakui, Yuta Fujimori, Hisako Katagiri, Shoko Nakamura, Yoshino Kondo, Yuko Kuroda, Terumichi Nakagawa, Nobuko Shimizu, Mitsuru Murata

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Aims: Clot waveform analysis (CWA) has been reported to extend the interpretation of clotting time measurement. The parameters obtained from successive derivatives of the clotting reaction curves reflect the rates of activation of individual coagulation factors, theoretically dissecting the cascade pathway. This study aims to assess the in vitro effects of direct thrombin inhibitors (DTIs) and activated factor X (FXa) inhibitors. Methods: CWA was applied to the activated partial thromboplastin time (APTT) assay of plasma samples spiked with each drug. For CWA of APTT measurement curves (APTT-CWA), the positive mode of clotting reaction curves was defined as the direction towards fibrin generation. Results: All the maximum positive values in the successive derivatives were decreased dependently on the concentrations of each drug. Moreover, the negative values in the second and third derivatives appeared putatively due to consumption of thrombin and factor FXa, respectively, to form complexes with plasma serine protease inhibitors. The decrease of the maximum negative values observed dependently on the concentrations of each drug appeared to be consistent with the decreased generation of thrombin and factor FXa. The analysis of Hill coefficients of each drug in the dose-response of changes in the APTT-CWA parameters revealed a difference in anticoagulant cooperativity between DTIs versus FXa inhibitors. Conclusions: The APTT-CWA demonstrated evidence for the blockade of thrombin-positive feedback by DTIs and FXa inhibitors and that for the differences in anticoagulant cooperativity between them. The results demonstrate the usability of CWA for assessment of anticoagulation and provide insights into direct anticoagulants.

Original languageEnglish
JournalJournal of Clinical Pathology
DOIs
Publication statusAccepted/In press - 2018 Jan 1

Keywords

  • APTT
  • clot waveform analysis
  • direct FXa inhibitors
  • direct thrombin inhibitors
  • thrombin positive feedback

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

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