Application of Activators Ecarin and Factor Xa in Thrombelastography for Measurement of Anticoagulant Effect of Direct Oral Anticoagulants Using TEG 5000

Abstract

There are situations where monitoring direct oral anticoagulants (DOACs) would be useful, including bleedings and trauma. The thromboelastographic technique has proven useful in bleeding situations in trauma and heart surgery. The aim of this study was to examine the effect of DOACs on all currently commercially available conventional TEG®5000 assays as well as novel modified assay using Ecarin and human factor Xa (HFXa). Healthy male volunteers were given single dose of oral dabigatran 150 mg, rivaroxaban 20 mg, or apixaban 5 mg. Kaolin, RapidTEG, functional fibrinogen, PlateletMapping assay, and novel modified assays using Ecarin and HFXa were prepared. All TEG parameters were recorded. DOAC concentrations were correlated to the parameters with highest response to the DOAC effect. Sensitivity and negative predictive value of the parameter with highest response to DOAC concentration of 50 ng/mL was calculated. None of the conventional TEG assays demonstrated significant response to the effect on apixaban. Using Ecarin, reaction time R was strongly correlated with dabigatran concentrations. Using HFXa assay, R was strongly correlated with rivaroxaban and apixaban concentrations: r = 0.96, 0.84, and 0.86, respectively; p < 0.0001 for all. The R times obtained with the modified assays demonstrated strong sensitivity and negative predictive values for DOAC levels of ≥50 ng/mL. We have demonstrated that TEG®5000 can monitor the DOAC effect on hemostasis when the appropriate activator is used with significant correlation with DOAC concentrations. Larger clinical studies are warranted for correlation of TEG profile and clinical outcomes.

Nomogram model combined thrombelastography for venous thromboembolism risk in patients undergoing lung cancer surgery

“…The greatest use has been in guiding transfusion strategies for surgical patients, such as in situ liver transplantation and extracorporeal circulation, where there is a risk of major bleeding (Kang, 1995;Spiess et al, 1995). In recent years, the use of TEG in drug monitoring and patient screening has led to a renewed interest in this technique (Davies et al, 2015;Artang et al, 2022). In this study, K and R of TEG were found to be independent risk factors for the development of VTE postoperatively and contributed the most in the nomogram.…”

Emerging Use of Viscoelastography in Thrombosis and Hemostasis: A Challenge to Conventional Coagulation Tests? Part I: The Use of Thromboelastography and Thromboelastometry in the Assessment of Hemostatic Function

“…Such advantage is fully utilized in the management of trauma patients, as discussed previously by Moore and colleagues, and in the current issue by Meizoso et al 4,5 Another potential application of this methodology is in the monitoring of anticoagulant therapy. 6 This is especially useful in patients with marked variation in the coagulation status such as in complicated cases in the emergency department. This is followed in this issue by the use of viscoelastographic tests in patients on mechanical circulatory support devices such as for extracorporeal membrane oxygenation.…”