Abstract 12590: Usefulness of Trough Level of Activated Partial Thromboplastin Time to Predict Bleeding Events in Clinical Use of Dabigatran for Patients With Atrial Fibrillation
Background: Usefulness of activated partial thromboplastin time (APTT) to predict bleeding events in clinical use of dabigatran was reported in previous study. However, it is unknown whether the peak level of APTT or the trough level of APTT is more useful.
Methods: A total of 466 patients with atrial fibrillation (AF) who had been given dabigatran (298 men, mean age: 70.9±11.5 years) were enrolled from April 2011 to June 2012. In this study, 275 patients were followed for more than three months by our medical records and questionnaires to referred medical institutions. Among those patients, we checked APTT in 202 out-patients and 52 in-patients. The normal range of APTT was from 30.3 to 45.4 seconds in our hospital. According to the hours after oral administration, APTT was classified into two groups: peak group (1-4 hours) and trough group (0-1 or 4-12 hours).
Results: The peak and trough groups were respectively consisted of 120 and 134 patients. Bleeding events occurred in 26 patients (10.2%), 5 of those had major bleeding events (4 gastrointestinal, 1 intracranial). Comparing APTT ≥70 patients (n=26) with APTT ≤70 patients (n=228), the bleeding event rate was significantly higher in APTT ≥70 patients (26.9% vs. 8.3%; p=0.003). In the trough group, APTT ≥70 patients had a higher bleeding event rate than APTT ≤70 patients (23.1% vs. 5.0%; p=0.01). There was no significant difference in the peak group (30.8% vs. 12.1%; p=0.07). In logistic multivariate analysis, APTT was an independent determinant factor to predict bleeding events (See the table).
Conclusion: In the clinical use of dabigatran for AF, the bleeding event rate was significantly higher in patients with prolonged APTT ≥70 than those with APTT ≤70. From this study, the trough level of APTT may be more useful than the peak level of APTT to predict bleeding events.
- © 2013 by American Heart Association, Inc.