Abstract Number: PB1094
Meeting: ISTH 2022 Congress
Background: The prothrombinase-induced clotting time (PiCT) is proposed as a rapid and inexpensive laboratory test to measure direct oral anticoagulant (DOAC) drug levels.
Aims: We aimed to study the accuracy of PiCT to determine rivaroxaban, apixaban, and edoxaban drug concentrations and assessed whether clinically relevant drug levels could be predicted correctly.
Methods: This analysis was conducted as part of the Simple-Xa study, a prospective multicenter cross-sectional study including 932 patients treated with rivaroxaban, apixaban, or edoxaban. Citrated plasma samples were collected, and the Pefakit® PiCT was conducted on a Siemens Atellica Coag 360. Ultra-high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) was done to determine drug concentrations. Cut-off levels were determined using receiver-operating characteristics curves (ROC) and sensitivities regarding clinically relevant drug concentrations calculated (30 mg L-1; 50 µg L-1; 100 µg L-1).
Results: Samples of 851 individuals were available for the current analysis (apixaban, n=414; rivaroxaban, n=373; edoxaban, n=64). The median age was 76 (IQR 66 to 83), and 360 patients were female (42.7%). The correlation (Spearman’s correlation coefficient) between PiCT and drug concentrations was 0.85 in case of rivaroxaban (95% CI 0.82, 0.88), 0.66 in apixaban (95% CI 0.60, 0.71), and 0.78 in edoxaban (95% CI 0.65, 0.86). The sensitivity to detect clinically relevant drug concentrations was 85.1% in case of 30 µg L-1 (95% confidence interval [CI] 82.0, 87.7; specificity 77.9, 95%CI 72.1, 82.7), 85.7% in case of 50 µg L-1 (95% CI 82.4, 88.4; specificity 77.3, 95% CI 72.5, 81.5), and 85.1% in case of 100 µg L-1 (95% CI 80.9, 88.4; specificity 73.2%, 95% CI 69.1, 76.9). The distribution of PiCT in patients with and without clinically relevant concentrations is shown in Figure 1.
Conclusion(s): Overall, the association of PiCT with rivaroxaban, apixaban, and edoxaban drug concentrations was moderate, but the majority of clinically relevant drug levels were predicted correctly.
To cite this abstract in AMA style:Sathanantham V, Studt J, Mendez A, Alberio L, Fontana P, Wuillemin W, Schmidt A, Graf L, Gerber B, Mäder G, Bovet C, Sauter T, Nagler M. Prothrombinase-induced clotting time for the measurement of rivaroxaban, apixaban, and edoxaban drug concentrations: a cross-sectional study [abstract]. https://abstracts.isth.org/abstract/prothrombinase-induced-clotting-time-for-the-measurement-of-rivaroxaban-apixaban-and-edoxaban-drug-concentrations-a-cross-sectional-study/. Accessed September 27, 2023.
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