Dabigatran is a novel oral anticoagulant exclusively directed against thrombin. Its efficacy and safety were shown to be at least as good as those of vitamin K antagonists (warfarin) for the prevention and treatment of thrombotic disease in patients with atrial fibrillation and venous thromboembolism, respectively. In this study, the authors have analyzed reports of major bleeding in 5 major trials comparing dabgatran with warfarin in these patient categories.
Interestingly, patients who experienced a major hemorrhagic complication with dabigatran had a higher risk profile for bleeding (they were older, had more severely impaired renal insufficiency, and used more often NSAIDs). Bleeding patients on dabigatran received more red cell concentrates (61% vs. 42%; P < 0.001) but less plasma (20% vs. 30%; P < 0.001) compared to warfarin-treated patients with bleeding. Patients requiring intensive care treatment upon major hemorrhage associated with the use of dabigatran had a shorter length of ICU stay (1.6 nights) compared to warfarin patients (2.7 nights). There was a trend towards a lower 30-day mortality in bleeding patients with dabigatran compared to warfarin (odds ratio 0.66; 95% confidence interval, 0.44-1.0). This is interesting information that adds to the safety profile of dabigatran. Again, it was shown that dabigatran is at least as safe as warfarin and may be associated with a slightly less harmful safety profile. The difference in use of plasma may be explained by the fact that plasma is an effective reversing agent for warfarin, but most probably not for dabigatran and may be used more often in countries where prothrombin complex concentrates are not available (such as the US). The trade-off is more pronounced blood loss in the dabigatran-treated patients at the expense of more red cell transfusions. Also the higher incidence of gastrointestinal bleeding in the dabigatran group may explain the difference in red cell transfusion. Nevertheless, dabigatran-treated patients had (a trend towards) a more beneficial outcome of clinically relevant outcomes. Lastly, it is remarkable how many warfarin-treated patient with major hemorrhage did not receive appropriate prohemostatic measures, such as administration of vitamin K, which may have affected the worse outcome in these patients. – Marcel Levi