Background Direct-acting oral
anticoagulants (DOACs) do not require monitoring. Measurement of DOAC effect would be useful in the event of
bleeding,
trauma, and
thromboembolism while on anticoagulation. We evaluated the effectiveness of the investigational DOAC assays on the TEG®6s Hemostasis Analyzer to assess the
anticoagulant effect of DOACs in patients treated for
atrial fibrillation or
deep vein thrombosis (DVT). Methods Patients on treatment for a minimum of 7 days with standard doses of
dabigatran,
rivaroxaban, and
apixaban were included. DOAC plasma concentrations and TEG®6s Reaction (R)-time were measured and correlated. The sensitivity, specificity, and negative predictive value (NPV) of R-time to detect DOAC concentrations of ≥30, ≥50, and ≥100 ng/mL were calculated. Results A total of 189 patients were included, ( n = 50) on
apixaban, ( n = 62) on
rivaroxaban, ( n = 53) on
dabigatran, and ( n = 24) on no DOAC were studied. Using the
direct thrombin inhibitor (DTI) channel, R-time demonstrated strong linear correlation with
dabigatran levels (r = 0.93, p < 0.0001). Using the antifactor Xa (AFXa) channel, R-time demonstrated strong nonlinear correlation with
rivaroxaban and
apixaban levels ( r s = 0.92 and 0.84, respectively, p < 0.0001 for both). R-time revealed strong sensitivity and NPV in detecting low DOAC levels for the predefined concentrations. Conclusion R-time measured by TEG®6s DOAC-specific cartridge has a strong correlation with concentrations of the most commonly used DOACs with high sensitivity and NPV for detecting lower drug levels that are considered clinically relevant for patients in need of
antidote, or prior to urgent surgery. Further studies to determine the relation of R-time to clinical outcomes are warranted.