The authors regret that in the above article the sentence that appears in the conclusion on page 121, lines 14–15 is incorrect. The sentence should read: “However, as DFPP removes large amounts of fibrinogen, FXIII and VWF, patients may have an increased bleeding risk, …” The authors would like to apologise for any inconvenience caused. Effect of double-filtration plasmapheresis for antibody-mediated rejection on hemostasis parameters and thrombin generationThrombosis ResearchVol. 166PreviewDonor-specific alloantibodies (DSAs) cause kidney-allograft loss in chronic antibody-mediated rejection (CAMR). Treatment relies on blocking antibody-producing cells and removing DSAs by apheresis: e.g., double-filtration plasmapheresis (DFPP). Full-Text PDF

We read with great interest the recent article by Jaffer et al. 1.Jaffer I.H. Chan N. Roberts R. Fredenburgh J.C. Eikelboom J.W. Weitz J.I. Comparison of the ecarin chromogenic assay and diluted thrombin time for quantification of dabigatran concentrations.J Thromb Haemost. 2017; 15: 2377-87Abstract Full Text Full Text PDF PubMed Scopus (14) Google Scholar comparing the ecarin chromogenic assay (ECA) and the diluted thrombin time (dTT) assay with HPLC mass spectrometry (HPLC/MS) for the quantification of dabigatran levels in plasma. In their study, the ECA was performed with an STA‐ECA‐II kit with STA dabigatran calibrators (Diagnostica Stago, Asnières sur Seine, France), and the dTT assay was performed with the Hemoclot Thrombin Inhibitor (HTI) assay (Hyphen BioMed, Neuville‐sur‐Oise, France). Both assays were performed on an STA‐R Evolution analyzer. The authors correlated drug levels measured with either the ECA or the dTT assay with levels determined by HPLC/MS over a wide range of dabigatran levels. They found a significant non‐linear association between levels measured with the ECA and those measured with HPLC/MS methods. They observed an increasing divergence at higher dabigatran levels that resulted in a significant overestimation of dabigatran levels, especially for levels of > 250 ng mL−1. The authors suggested that the non‐linearity might be explained by the automated dilution performed by the STA‐R coagulometer for levels exceeding 270 ng mL−1. On the other hand, the authors found a linear association between dabigatran levels determined with the dTT and with HPLC/MS methods despite a slight overestimation of levels with the dTT assay. Jaffer et al. stated that both methods (ECA and dTT) showed good performance in terms of sensitivity and specificity. We also performed a comparison of the ECA and the dTT assay with HPLC/MS (data not previously published). For this purpose, residual plasmas from 51 blood samples from patients receiving dabigatran treatment were collected and stored at − 80 °C after a double centrifugation at 2500 × g at 19 °C in two French centers (center 1, n = 39; center 2, n = 12). Blood was initially collected in vacutainer tubes (Becton Dickinson, Le Pont de Claix, France) containing 0.109 m trisodium citrate. The ECA was performed with the STA‐ECA‐II kit with STA dabigatran calibrators (Diagnostica Stago) (five levels at 0, 52, 106, 182 and 270 ng mL−1) according to the manufacturer's instructions. For levels of > 230 ng mL−1, a second dilution, by half, of plasma was automatically performed (1/10 instead of 1/5 in Owren Koller buffer). The dTT assay was performed with the HTI assay (Hyphen BioMed) with the dabigatran standards (Hyphen Biomed) (three levels at 35, 240 and 470 ng mL−1) according to the manufacturer's instructions. Both assays were performed on a STA‐R Evolution coagulometer in the same centers in which samples were collected. The dTT assay and the ECA were conducted simultaneously on plasma samples. For determination of the level of total dabigatran (sum of free dabigatran + dabigatran glucuronide) by HPLC/MS, stored plasma samples from both centers were shipped to the Chemistry Department of Diagnostica Stago (Genevilliers, France). HPLC/MS was performed after alkaline cleavage of dabigatran conjugates with a method similar to that described by Stangier et al. 2.Stangier J. Rathgen K. Stähle H. Gansser D. Roth W. The pharmacokinetics, pharmacodynamics and tolerability of dabigatran etexilate, a new oral direct thrombin inhibitor, in healthy male subjects.Br J Clin Pharmacol. 2007; 64: 292-303Crossref PubMed Scopus (820) Google Scholar. Ranges of measurement were 1–1000 ng mL−1 for HPLC/MS, 15–460 ng mL−1 for the ECA, and 30–500 ng mL−1 for the dTT assay. Our results are slightly discordant with those published by Jaffer et al. 1.Jaffer I.H. Chan N. Roberts R. Fredenburgh J.C. Eikelboom J.W. Weitz J.I. Comparison of the ecarin chromogenic assay and diluted thrombin time for quantification of dabigatran concentrations.J Thromb Haemost. 2017; 15: 2377-87Abstract Full Text Full Text PDF PubMed Scopus (14) Google Scholar regarding the non‐linearity between the ECA and HPLC/MS for dabigatran levels of > 250 ng mL−1. We performed statistical analyses with r statistical software (Foundation for Statistical Computing, Vienna, Austria). We built a linear model predicting ECA (and dTT) results on the basis of HPLC/MS measurements. To detect departure from linearity, a quadratic term was incorporated into this model. If this term was statistically different from zero, non‐linearity was deemed to be present. When we analyzed all data, considering ECA values of < 15 ng mL−1 at a level of 15 ng mL−1, as Jaffer et al. did, we did not find non‐linearity between the ECA and HPLC/MS (R2 = 0.964, Pnon‐linearity = 0.365). When we excluded values of < 15 ng mL−1 (n = 5) to remove the influence of the two different lower limits of measurement (< 15 ng mL−1 for the ECA and < 1 ng mL−1 for HPLC/MS), we obtained a similar result (R2 = 0.977, Pnon‐linearity = 0.743). Our results are in accordance with those published by Gosselin et al. 3.Gosselin R. Hawes E. Moll S. Adcock D. Performance of various laboratory assays in the measurement of dabigatran in patients receiving therapeutic doses: a prospective study based on peak and trough plasma levels.Am J Clin Pathol. 2014; 141: 262-7Crossref PubMed Scopus (32) Google Scholar, who reported a linear relationship between the ECA and a mass spectrometry assay in a multicenter study for levels up to 500 ng mL−1. However, our analysis may be limited by the lower number of values above 250 ng mL−1 (n = 5 in our work and n = 10 in the work of Jaffer et al.). Concerning the dTT assay (Fig. 1B), our results are consistent with those published by Jaffer et al. Although we initially found statistically significant non‐linearity (R2 = 0.838, Pnon‐linearity = 3.61 × 10−4) when we analyzed all data (although it was non‐biologically significant, with a value of 5 × 10−4), we found a linear relationship between dTT and HPLC/MS values (R2 = 0.990 and Pnon‐linearity = 0.890) when we excluded values of < 30 ng mL−1. The non‐linearity observed when all data were incorporated was attributable to the two different lower limits of measurement for HPLC/MS (< 1 ng mL−1) and the dTT assay (< 30 ng mL−1). Indeed, values of > 30 ng mL−1 obtained with the dTT assay (n = 16), considered to be 30 ng mL−1 for the analysis, corresponded to levels between 11 ng mL−1 and 37 ng mL−1 obtained with HPLC/MS. Unlike Jaffer et al., we simultaneously performed the dTT assay and ECA, without a freezing–thawing step between the dTT assay and the ECA. We could therefore perform a correlation between the ECA and the dTT assay (Fig. 1C). This analysis showed an excellent correlation and a linear relationship between the two methods (R2 = 0.972 and Pnon‐linearity = 0.113 when we analyzed all data where values of < 15 ng mL−1 obtained with the ECA were considered as 15 ng mL−1, and values of < 30 ng mL−1 obtained with the dTT assay were considered as 30 ng mL−1; and R2 = 0.966 and Pnon‐linearity = 0.583 when values of < 30 ng mL−1 were excluded, n = 5). In our data, we did not find a significant overestimation of dabigatran levels with the ECA or the dTT assay at higher levels. Mean biases (ng mL−1) for the ECA and the dTT assay as compared with HPLC/MS were found to be, respectively, + 0.2 (95% confidence interval [CI] − 12 to 12) and − 9.1 (95% CI − 24 to 5.8) for 50–100 ng mL−1 levels, − 11 (95% CI − 47 to 26) and − 5.0 (95% CI − 33 to 23) for 100–200 ng mL−1 levels, and − 0.6 (95% CI − 56 to 50) and + 9 (95% CI 0.4–36) for 200–500 ng mL−1 levels. Finally, we also tested the reliability of the ECA and the dTT assay for identifying low dabigatran levels. We constructed receiver operating characteristic curves for HPLC/MS levels lower than 30 ng mL−1 or 50 ng mL−1, corresponding to the safety cut‐offs generally recommended for surgery 4.Pernod G. Albaladejo P. Godier A. Samama C.M. Susen S. Gruel Y. Blais N. Fontana P. Cohen A. Llau J.V. Rosencher N. Schved J.F. de Maistre E. Samama M.M. Mismetti P. Sié P. Working Group on Perioperative HaemostasisManagement of major bleeding complications and emergency surgery in patients on long‐term treatment with direct oral anticoagulants, thrombin or factor‐Xa inhibitors. Proposals of the Working Group on Perioperative Haemostasis (GIHP) – March 2013.Ann Fr Anesth Reanim. 2013; 32: 691-700Crossref PubMed Scopus (64) Google Scholar, 5.Eikelboom J.W. Weitz J.I. Dabigatran monitoring made simple?.Thromb Haemost. 2013; 110: 393-5Crossref Scopus (10) Google Scholar. The sensitivities at the 30 ng mL−1 and 50 ng mL−1 cut‐offs (to detect levels lower than 30 ng mL−1 or 50 ng mL−1 according to the HPLC/MS method) were 100% for both cut‐offs and both assays (ECA and dTT). The specificities (for detecting levels higher than 30 ng mL−1 or 50 ng mL−1) were, respectively, 97.4% and 97.4% for the ECA, and 89.7% and 91.2% for the dTT assay. These results are highly consistent with those published by Jaffer et al. 1.Jaffer I.H. Chan N. Roberts R. Fredenburgh J.C. Eikelboom J.W. Weitz J.I. Comparison of the ecarin chromogenic assay and diluted thrombin time for quantification of dabigatran concentrations.J Thromb Haemost. 2017; 15: 2377-87Abstract Full Text Full Text PDF PubMed Scopus (14) Google Scholar. In conclusion, like Jaffer et al., we found that both assays (ECA and dTT) have very good correlation with HPLC/MS, together with very good sensitivities and specificities. Both assays performed on an STA‐R Evolution platform provide accurate and rapid determination of dabigatran levels over a wide range of dabigatran plasma levels. R. Marlu supervised the research, collected the data, analyzed the results, and wrote a first draft of the manuscript, which was then finalized on the basis of critical feedback by all co‐authors. T. Jouve performed the statistical analyses. B. Polack and P. Sié critically revised the manuscript. V. Mémier supervised the research, collected the data, and analyzed the results. All authors approved the final version of the manuscript. The authors state that they have no conflict of interest. We gratefully acknowledge Diagnostica Stago for providing us with ECA‐II kits for the study and for performing the quantification of dabigatran levels by HPLC/MS. We thank the laboratory technicians who performed the assays. We also thank A. M. Foote (Grenoble Alpes University Hospital) for critically editing the manuscript.

Introduction Donor-specific alloantibodies (DSAs) cause kidney-allograft loss in chronic antibody-mediated rejection (CAMR). Treatment relies on blocking antibody-producing cells and removing DSAs by apheresis: e.g., double-filtration plasmapheresis (DFPP). Materials and methods To determine the impact of DFPP (6 or 8 sessions/patient) on clotting factors and natural anticoagulants, and on thrombin generation, we performed a prospective and observational study in five CAMR kidney-transplant patients who received DFPP plus rituximab therapy. Thrombin generation was performed in poor platelet plasma (PPP) with 5 pM tissue factor without and with 2 nM recombinant human thrombomodulin. Results After the first DFPP session, median levels of high molecular-weight proteins (fibrinogen, FV, FVIII, FXI, FXIII, von Willebrand factors and α2-MG) decreased significantly to <50% of baseline values, whereas levels of low molecular-weight factors (<100 kDa) were not significantly modified, except for protein S and TFPI. Of note, binding-protein (BP) S, i.e., C4BP, was significantly decreased. Over the course of successive DFPP sessions, both high and lower molecular-weight proteins (<100 kDa) with longer half-lives (>2 days, prothrombin and factor XII) were significantly decreased. DFPP also highly affected thrombin generation in the absence of thrombomodulin but not significantly in the presence of thrombomodulin. After the first DFPP session, mean endogenous thrombin potential (ETP) and peak thrombin (PH) significantly decreased when the thrombin generation assay was performed without thrombomodulin (respectively, 1084 nM·min for ETP and 210 nM for PH after the first DFPP session compared to 1616 nM·min and 264 nM at baseline). In the presence of thrombomodulin, there was only a slight decrease in ETP and PH (respectively 748 nM·min, and 172 nM after the first DFPP session compared to 822 nM·min and 179 nM at baseline). After the last session, median ETP and PH decreased respectively to 646 nM·min and 143 nM without thrombomodulin, and, to 490 nM·min and 117 nM with thrombomodulin. Conclusions DFPP significantly removed high molecular-weight proteins from the haemostatic system and profoundly decreased levels of protein S and TFPI. Overall thrombin-generation balance was only moderately affected in the presence of thrombomodulin. Nevertheless, high depletion of fibrinogen, FXIII and Von Willebrand Factor may expose patients to an increased risk of bleeding.

Objective: Asprin resistance is more frequent in diabetes and is associated with a poor health outcome. Intermitent hypoxemia in patient with obstructive sleep apnea (OSA) is associated with platelet activation. OSA is frequent in patient with diabetes mellitus. The aim of this study was to investigate the role of the OSA in aspirin resistance in diabetes. Design and method: Patients with diabetes mellitus, taking aspirin for primary prevention or stable atherothrombotic disease, underwent overnight, in-lab polysomnography. The following morning we used the VerifyNow aspirin system to evaluate the efficacy of aspirin. Patients with at least an apnea-hypopnea index of 30 events/hours were diagnosed with severe OSA. Results: The preliminary result of the fifty first consecutive patients included in the study is presented:Conclusions: In these preliminary results, the OSA seems not be influence the aspirin response in patients with diabetes.

Rotational Thromboelastometry (ROTEM) is a point of care method used to monitor coagulation during surgery and to guide transfusion strategies in patients presenting with severe bleeding. The aim of our study was to determine the impact of four direct oral anticoagulants (DOACs) on 3 commonly used ROTEM tests.

Scarce data is available on the economic burden associated with haemophilia B (HB). The aim of this study was to evaluate in a representative French HB population the impact on health-related quality of life (HRQOL) and to estimate the costs associated with its management. EQOFIX is a prospective cohort study in patients with moderate and severe HB with one year follow-up. Data collected included: patients' demographic and clinical characteristics, severity status, therapeutical approach, FIX consumption and all other resources used. Two types of HRQOL were used: generic (Kidscreen for children and SF-36 for adults) and specific (QUAL-HEMO, specific to haemophilia patients). The French national health insurance perspective was considered to estimate the average annual cost using official cost database. A total of 155 patients had been included by 27 centres, representing a coverage rate of 25% of the French global population suffering from severe and moderate HB: 104 adults (74 severe and 30 moderate) and 51 children (40 severe and 11 moderate). 30.4% of patients received preventive treatment; 60.4% were on-demand treatment. Severe HB adults reported significantly poorer HRQOL than the moderate subgroup mainly on physical components. No HRQOL difference was observed among children. The average annual direct cost was €95,619 (SD 83,142) with no significant difference between adults and children, but with a difference with severity status (3.3 times higher in severe vs. moderate HB, p<0.001). Substitutive therapy represented 90%, of the total followed by hospitalizations 6.5%. Even if the prophylaxis strategy lead to higher costs than an on-demand strategy (p<0.001), it allows avoiding haemorrhagic events and remains in acceptable cost-effectiveness range. To date, no economic burden of disease studies focusing only on HB have been published. The EQOFIX study provides an important source of economic information for health care payers.