Predictive Study of Thrombin Time Ratio on Bleeding Events in Nonvalvular Atrial Fibrillation Patients Receiving Dabigatran Etexilate

OBJECTIVE To find a new parameter to monitor bleeding tendency after dabigatran etexilate medication in nonvalvular atrial fibrillation patients.METHODS There conducted a retrospective cohort study including nonvalvular atrial fibrillation patients receiving dabigatran etexilate 110 mg bid between November 2018 and October 2019. In order to screen the best monitoring indexes, the clinical data from the medical records were obtained and compared between the long-term use group and first-time use group, the bleeding group and the no bleeding group. Logistic regression analyses were used to determine the related factors of bleeding. ROC curve was drawn in order to find the best cut-off value to predict bleeding events.RESULTS Total of 487 patients were included and the incidence of bleeding events was 14.1%(35/249) in the long-term use group. Six routine coagulation examinations(thrombin time/thrombin time ratio, activated partial thromboplastin time/activated partial thromboplastin time ratio, prothrombin time/international normalized ratio) were assayed. Logistic regression analyses identified the thrombin time(TT) ratio as the only independent variable associated with bleeding events. When using TT ratio to distinguish patients with and without bleeding events, the cut-off value was 16.25, while sensitivity was 31.4% and specificity was 94.0%. The area under the curve was 0.65.CONCLUSION This study demonstrates that TT ratio>16.25 is an independent risk factor for bleeding, and which maybe useful for assessment of bleeding risk in nonvalvular atrial fibrillation patients with dabigatran etexilate therapy.