Abstract Number: OC 65.5
Meeting: ISTH 2022 Congress
Background: Anti-factor Xa (anti-FXa) assays used to monitor unfractionated heparin (UFH) may vary in their responsiveness to UFH. Since dextran sulfate (DS) dissociates the UFH/neutralizing protein complexes, its presence in reagents could contribute to this heterogeneity.
Aims: To evaluate in a prospective multicenter non-interventional study the effect of different reagents, containing or not DS, and of blood collection tubes, on anti-FXa levels in patients receiving UFH.
Methods: In-patients from 8 centers receiving UFH were included: group (G)1, cardio-pulmonary bypass (CPB) 5-10 min after protamine neutralization (n=39); G2, intensive care unit (ICU) 1-5 days after CPB (n=35); G3, medical ICU (n=53); G4, medical patients (n=38). For each patient, blood was collected into both citrated/citrate-theophylline-adenosine-dipyridamole (CTAD) tubes. Anti-FXa assays were centrally assessed, using five commercially available chromogenic assays, including two without DS, on both citrated/CTAD plasma samples, with different analyzers. We used a linear mixed-effects model to evaluate the potential effect of DS and citrate/CTAD on anti-FXa levels.
Results: Citrated and CTAD plasma samples from 165 patients were analyzed. Table 1 shows the anti-FXa values according to reagents, analyzers and tubes (n=2273). The model showed that anti-FXa levels were 15.1% higher in CTAD than in citrated tubes (95% confidence interval [+8.7;+21.9]), whatever the group. Reagents containing DS led to higher anti-Xa values than those without, especially in G1 (Table 2). Accordingly, in CPB patients after protamine neutralization (G1), on citrate tubes, 6% of the assays with DS versus 77% of the assays without DS had anti-FXa level below the limit of quantification (0.1 IU/mL; Table 2).
Conclusion(s): The observed variability according to reagents and tubes could lead to different treatment decision-making. In critically-ill patients, anti-FXa results should be interpreted with caution and knowledge of the performances of the reagents in the context of UFH neutralization or dose adjustment decision.
To cite this abstract in AMA style:Lasne D, Toussaint-Hacquard M, Delassasseigne C, Bauters A, Flaujac C, Savard P, Mouton C, De Maistre E, STEPANIAN A, Georges J, Gros A, Mansour A, Leroy G, Jouffroy R, Mattei M, PONTIS A, NEUWIRTH M, Curis E, Siguret V, Gouin I. Factors influencing anti-Xa assays in different groups of critically ill and non-critically ill patients receiving unfractionated heparin: a multicenter prospective study [abstract]. https://abstracts.isth.org/abstract/factors-influencing-anti-xa-assays-in-different-groups-of-critically-ill-and-non-critically-ill-patients-receiving-unfractionated-heparin-a-multicenter-prospective-study/. Accessed November 30, 2023.
« Back to ISTH 2022 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/factors-influencing-anti-xa-assays-in-different-groups-of-critically-ill-and-non-critically-ill-patients-receiving-unfractionated-heparin-a-multicenter-prospective-study/