Introduction: Direct oral anticoagulants (DOACs) are mainly used in the prevention of thromboembolic complications in patients with atrial fibrillation (AF) and in the treatment of venous thromboembolism. As compared with warfarin, although routine monitoring is not required in therapeutic decision of DOACs, monitoring plasma DOACs concentration is important in specific clinical setting. Recently, we demonstrated that Total Thrombus-formation Analysis System (T-TAS) might be a useful tool in monitoring anticoagulant effects of direct oral anticoagulants and a predictor of bleeding events in AF patients undergoing radiofrequency catheter ablation (CA).
Hypothesis: In this study, we evaluated the usefulness of T-TAS for predicting bleeding risk by comparing with plasma DOACs concentration.
Methods: After exclusion of 107 from 212 consecutive patients, the remaining 105 consecutive patients underwent CA for AF treated with DOACs [dabigatran (n=19), rivaroxaban (n=54), and apixaban (n=32)] were enrolled at our hospital between August 2013 and February 2016 and analyzed. Blood samples obtained on 3 days (trough and peak) after CA were used in T-TAS to compute thrombus formation area under the curve (AUC) (AR10-AUC30, AUC for AR chip). Plasma DOACs concentrations were measured by chromogenic assay for direct Factor Xa Inhibitors and clotting assays for direct thrombin inhibitors. Fifteen patients were observed periprocedural bleeding events within 30 days after CA.
Results: AR10-AUC30 levels at trough and peak points were significantly lower in bleeding than non-bleeding groups (p<0.001, p=0.046, respectively) while there were no significant differences in plasma DOACs concentrations. Multiple logistic regression analysis identified low AR10-AUC30 levels but not high DOACs concentration as a significant predictor of periprocedural bleeding events (OR 8.4; 95%CI: 1.79 to 39.7; p=0.007, OR 0.78; 95%CI: 0.25 to 2.48; p=0.677, respectively).
Conclusions: AR10-AUC30 level determined by T-TAS but not plasma DOACs concentrations is a potentially useful marker for predicting periprocedural bleeding events in AF patients undergoing CA.