Background: A rapid assessment of the dabigatran anticoagulant effect is desirable for both dabigatran treated patients before emergent surgical procedures and for patients with hemorrhage or thrombosis. Specific assays for measuring dabigatran plasma concentration are not widely available. Rotational thromboelastometry (ROTEM) is a point-of-care testing device used to monitor hemostasis. Therefore, it would be useful to determine relative sensitivity of a ROTEM parameters to dabigatran.

Aims: To assess the effect of trough dabigatran plasma concentration on ROTEM parameters.

Methods: Blood was collected into 3.2% Na-citrate tubes (BD Vacutainer) from 12 patients taking 150 mg bd dabigatran for thromboprophylaxis. Viscoelastic analysis of whole blood was performed on ROTEM using EXTEM and INTEM tests (Werfen). Dabigatran levels in plasma were measured by ecarin chromogenic assay using STA-ECA II assay on the STA-R Evolution analyser (Stago).

Results: Mean dabigatran trough concentrations were 65.3 ng/ml ± 37.9 SD. Spearman’s coefficient of rank correlation (rho) was statistically significant between dabigatran concentration and CT EXTEM (rho=0.832; CI 0,494 to 0,952, p=0,005) and CT INTEM (rho=0.839; CI 0,512 to 0,954, p=0,005). There was no statistically significant correlation between dabigatran concentration and other ROTEM parameters: CFT, MCF and alpha angle. CT EXTEM was prolonged (>79 s) in 9 out of 12 samples. CT INTEM was prolonged (>240 s) in 8 out of 12 samples. Both CT EXTEM and CT INTEM were normal in 2 out of 12 samples were dabigatran concentration were <56 ng/ml.

Conclusions: We demonstrated that trough dabigatran concentrations corelate well with CT EXTEM and CT INTEM. Normal levels for both CT EXTEM and CT INTEM suggest drug concentration levels below 56 ng/ml. According to Eikelboom et al. most surgical procedures can safely be performed with dabigatran concentrations <50 ng/ml. Therefore, ROTEM tests EXTEM and INTEM can be useful for exclusion of higher levels of dabigatran.

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ISTH Congress Abstracts - https://abstracts.isth.org/abstract/the-effect-of-trough-dabigatran-plasma-concentration-on-rotational-thromboelastometry-parameters/