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Background: Thrombin generation testing has been used to provide information on the coagulation phenotype of patients. The most used technique is the calibrated automated thrombogram (CAT) but it suffers from a lack of standardization, preventing its implementation in routine. The ST Genesia is a new analyzer designed to assess thrombin generation based on the same principle as the CAT. Unlike the CAT system, the ST Genesia is a benchtop, fully automated analyzer, able to perform the analyses individually and not by batch, with strict control of variables such as temperature and volumes, ensuring, theoretically, maximal reproducibility., Objectives: This study aimed at assessing the performance of the STG-DrugScreen application on the ST Genesia analyzer. We also aimed at exploring stability of plasma samples after freezing and defining a reference normal range., Results: Results demonstrated the excellent interexperiment precision of the ST Genesia and confirmed that the use of a reference plasma helps reducing the inter-experiments variability. Stability revealed that plasma samples are stable for at least 11 months at -70°C or lower, except for those containing low molecular weight heparins which have to be tested within 6 months. Freezing had no effect on the majority of thrombin generation parameters except on time to peak., Conclusions: Our results suggest an easy implementation of thrombin generation with the use of ST Genesia in the routine laboratory. This will facilitate the design of multicentric studies and enable the establishment of reliable and evidence-based thresholds, which may improve the management of patients treated with anticoagulants., (© 2019 The Authors. Journal of Thrombosis and Haemostasis published by Wiley Periodicals, Inc. on behalf of International Society on Thrombosis and Haemostasis.)

The perioperative management of dabigatran is challenging, and recommendations based on activated partial thromboplastin time (aPTT) and thrombin time (TT) are unsatisfactory. Dedicated coagulation tests have limitations at plasma concentrations < 50 ng/ml. Therefore, a more sensitive test, which is available 24/7, is required. It was the aim of this study to investigate the performance of the Hemoclot Thrombin Inhibitors® LOW (HTI LOW) kit, a diluted thrombin time, and the STA® - ECA II(ECA-II) kit, a chromogenic variant of the ecarin clotting time, that were developed to measure low dabigatran concentrations, compared to reference dabigatran analysis by liquid chromatography tandem mass-spectrometry (LC-MS/MS). This study included 33 plasma samples from patients treated with dabigatran etexilate who had plasma concentrations < 200 ng/ml. HTI LOW and ECA-II were performed along with HTI, aPTT (STA®-C. K.Prest® and SynthasIL®) and TT (STA® - Thrombin). All procedures were performed according to recommendations by the manufacturers. Linear (or curvilinear) correlations and Bland-Altman analyses were calculated. For free dabigatran concentrations < 50 ng/ml, the R² of linear correlations were 0.69, 0.84 and 0.61, with HTI, HTI LOW and ECA-II, respectively. The R² for TT, STA®-C. K.Prest® and SynthasIL® were 0.67, 0.42 and 0.15. For HTI, HTI LOW and ECA-II, Bland-Altman analyses revealed mean differences of -6 ng/ml (95 %CI: -25-14 ng/ml), 1 ng/ml (95 %CI: -18-19 ng/ml) and -1 ng/ml (95 %CI: -25-23 ng/ml), demonstrating that tests dedicated to measuring low concentrations are more accurate than HTI. In conclusion, the use of HTI LOW or ECA-II to assess low plasma dabigatran concentrations is supported by our findings.

Introduction: Estimation of residual apixaban plasma concentrations may be requested in the management of emergencies. This study aims at assessing the performance of specific anti‐Xa assays calibrated with apixaban on real‐life samples with low apixaban plasma concentrations (<30 ng/mL) and on‐treatment ranges, with and without interference of low‐molecular‐weight heparin (LMWH). Methods: The performance of the STA®‐Liquid Anti‐Xa assay (STA® LAX) and the low and normal procedures of the Biophen®Direct Factor Xa Inhibitors (DiXaI) assay was tested on 134 blood samples, collected from patients on apixaban, wherefrom 74 patients received LMWH after apixaban cessation. The results were compared with the liquid chromatography coupled with tandem mass spectrometry (LC‐MS/MS) measurements. Results: The Biophen®DiXaI, Biophen®DiXaI LOW, and STA®LAX showed very good correlation with LC‐MS/MS measurements in patients without LMWH administration (Spearman r.95,.99, and.98, respectively). Their limits of quantitation were defined at 48, 24, and 12 ng/mL, respectively. The Bland‐Altman test measured mean bias (SD) at 5.6 (13.1), −2.5 (5.0), and −0.8 (6.1) ng/ml, respectively. The Spearman r of the Biophen®DiXaI decreased to 0.64 in presence of low apixaban concentrations. The Spearman r of the Biophen®DiXaI LOW and STA®LAX decreased to 0.39 and 0.26, respectively, in presence of LMWH. Conclusions: The accuracy of the low methodologies (Biophen®DiXaI LOW and STA®LAX) is slightly improved for low apixaban plasma concentrations, compared with the normal procedure of Biophen®DiXaI. The interference of LMWH on the low methodologies is measurable, however, less important than the previously reported interference of LMWH on rivaroxaban calibrated specific anti‐Xa assays. [ABSTRACT FROM AUTHOR]

Aims Patients receiving direct oral anticoagulants (DOACs) frequently undergo elective invasive procedures. Their management is challenging. We aimed to determine the optimal duration of DOAC discontinuation that ensures a minimal anticoagulant effect during the procedure. Methods and results This prospective multicentre study included 422 DOAC-treated patients requiring an invasive procedure. Pre-procedural DOAC concentration ([DOAC]) and routine haemostasis assays were performed to determine i/the proportion of patients who achieved a minimal pre-procedural [DOAC] (=30≤ng/mL) according to the duration of DOAC discontinuation, ii/the predictors of minimal [DOAC] and, iii/the ability of routine assays to predict minimal [DOAC]. Lastly, we assessed the predictors of peri-procedural bleeding events. The duration of DOAC discontinuation ranged from 1 to 218 h and pre-procedural [DOAC] from ≤=30 to 527 ng/mL. After a 49-72-h discontinuation, 95% of the [DOAC] were =30≤ng/mL. A 72-h discontinuation predicted concentrations =30≤ng/mL with 91% specificity. In multivariable analysis, duration of DOAC discontinuation, creatinine clearance <50 mL/min and antiarrhythmics were independent predictors of minimal pre-procedural [DOAC] (concordance statistic 0.869; 95% confidence interval: 0.829-0.912). Conversely, routine haemostasis assays were poor predictors. Last, creatinine clearance <50 mL/min, antiplatelets and high-bleeding risk procedures were predictors of bleeding events. Conclusion A last DOAC intake 3 days before a procedure resulted in minimal pre-procedural anticoagulant effect for almost all patients. Moderate renal impairment, especially in dabigatran-treated patients, and antiarrhythmics in anti-Xa-treated patients should result in a longer DOAC interruption. In situations requiring testing, routine assays should not replace DOAC concentration measurement. [ABSTRACT FROM AUTHOR]