Abstract Number: PB0062
Meeting: ISTH 2021 Congress
Background: Tissue-factor pathway inhibitor (TFPI) is an anticoagulant protein that exerts its activity by forming an inactive FXa-TFPI-TF-FVIIa quaternary complex. In plasma, TFPI is normally found at a concentration of about 70 ng/mL but many pathologies impact its level, modifying the hemostatic function of individuals. In COVID-19 patients, in spite of a hypercoagulability state, increased levels of TFPI up to 400 ng/mL were observed.
Aims: This study aimed to assess the impact of TFPI on thrombin generation assay (TGA), when performed on the Calibrated Automated Thrombogram (CAT) and on the ST-Genesia system.
Methods: Normal pooled plasma (NPP) constituted of 50 healthy individuals was used as matrix. Recombinant TFPI was spiked in NPP at five relevant plasma concentrations (0 [=Phosphate buffer saline], 50, 100, 200 and 400 ng/mL). TGA was assessed on both platforms by 3 independent runs and the triggering reagent was the STG-ThromboScreen-TM (Stago, France). The percentages of change from baseline were calculated for each TGA parameter.
Results: On both platforms, based on mean values, statistically significant differences were observed between the five tested concentrations (p-value<0.05). Though not statistically significant, percentages of change from baseline were more pronounced on the ST-Genesia compared to the CAT system, especially for the endogenous thrombin potential (ETP) (decrease of 25% and 17%, respectively), for the lag time (LT) (prolongation of 17% and 10%, respectively) and for the peak height (PH) (decrease of 47% and 35%, respectively).
Conclusions: Regarding the physiological role of TFPI, impact on the LT parameter was expected. On the other hand, the important inhibitory effect of TFPI on the ETP and PH is a novel observation. This study showed that TFPI levels impacted in a dose-dependent manner TGA performed either on the CAT or on the ST-Genesia system. Any acute or mechanistic situations in which TFPI levels may be impacted will thus interfere with TGA.
To cite this abstract in AMA style:Didembourg M, Douxfils J, Carlo A, Morimont L. Influence of Tissue-factor Pathway Inhibitor on Thrombin Generation Assay [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 1). https://abstracts.isth.org/abstract/influence-of-tissue-factor-pathway-inhibitor-on-thrombin-generation-assay/. Accessed September 24, 2021.
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