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

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.

Oral anticoagulation use in non-valvular atrial fibrillation patients in rural setting.

Background: The 2019 ACC/AHA/HRS guidelines established direct oral anticoagulants (DOACs) as first line therapy over warfarin for non-valvular atrial fibrillation (AF). Methods: Ambulatory clinic patients with non-valvular AF or atrial flutter seen between 10/1/2019-7/12/2020 included. High-risk AF defined as males CHA2DS2-VASc score ≥2 and females ≥3. Patients were separated into: warfarin, DOAC, or no oral anticoagulation (OAC). ATRIA bleed score calculated. A provider survey assessing knowledge and barriers to anticoagulation completed via REDCap between 3/5-4/16/2020. Results: Of 12,014 subjects with AF, 8,032 were high risk (mean age 75.9 ± 9.8 years; 57.5% male). There were 4,619 (57.1%) ≥ 75 years and 63.4% were rural dwelling. There was no significant difference between the number of subjects on anticoagulation before and after the guideline publication (75.6% vs. 75.7%, p = 0.79). Warfarin use decreased 2.3% over 1 year (39.3% to 37.0%), while DOACs increased 2.4% (36.2% to 38.7%, p < 0.001 for both). At 1-year, age, male gender, CHA2DS2-VASc score 4-6, hypertension, stroke and cardiology consult increased prescription of OAC (p<0.05). Vascular disease, high risk ATRIA bleed, renal disease, prior hemorrhage, and left atrial appendage occlusion were associated with decreased OAC use (p < 0.05). Left atrial appendage occlusion device use was low (<1%). In a survey, majority of providers noted bleeding risk (35.1%) and cost (25.0%) to be the biggest barriers to DOAC use. Conclusions: The new guidelines caused a slight increase in DOACs over time. Significant barriers to DOAC use exist in rural areas; one in four high risk AF patient remains without OAC therapy.