Abstract 164: Specific Point-of-Care Testing of Coagulation in Patients Treated With Non-Vitamin K Antagonist Oral Anticoagulants Part I (SPOCT-NOAC I)

Abstract

Introduction: Non-vitamin K antagonist oral anticoagulants (NOAC) are increasingly replacing vitamin K antagonists for prevention of thromboembolism in atrial fibrillation (AF) and venous thrombosis. Ischemic stroke rate in NOAC-treated AF-patients is 1-2% per year. Subsequently, stroke physicians face a growing number of NOAC-treated patients with acute stroke. Rapid assessment of coagulation in NOAC-treated patients is vital prior to thrombolysis, but existing point-of-care testing (POCT) is suboptimal. For the first time we evaluate NOAC-specific POCT. Hypothesis: Ecarin clotting time (ECT)- and anti-Xa activity-POCT accurately predict plasma concentrations of dabigatran and apixaban/edoxaban/rivaroxaban. Methods: 80 patients receiving first NOAC-dose and 80 already on NOAC-treatment will be enrolled (N=40 for each NOAC). Subjects receiving other anticoagulants will be excluded. 6 blood samples will be collected from each patient: before drug intake, 30min, 1, 2, and 8h after intake, and before next dose. NOAC-concentrations will be measured by mass spectrometry. Results (preliminary): Until now 138 blood samples of 23 dabigatran-treated patients were analyzed. Dabigatran-concentrations ranged from 0-371ng/mL. ECT-POCT ranged from 20-219s. Pearson’s correlation coefficient showed strong correlation for ECT-POCT and dabigatran-concentrations (r=0.94, p<0.001). Dabigatran-concentrations >50ng/mL (threshold for thrombolysis according to expert recommendation) were detected by ECT-POCT (>50s) with 100% sensitivity and 82% specificity. Baseline-samples not containing any dabigatran yielded normal ECT-POCT. Conclusions: This is the first study evaluating NOAC-specific POCT. Preliminary results show excellent correlation for ECT-POCT and dabigatran; relevant dabigatran-concentrations were detected in 100%. More pioneering results on NOAC-specific POCT will be presented.