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Published on: February 28, 2012
Dabigatran versus warfarin after bioprosthesis valve replacement for the management of atrial fibrillation
Andre Rodrigues Duraes1, Pollianna Ds Roriz, Fabio V Bulhoes
1Hospital Ana Nery, Serviço de Cardiologia, Universidade do Estado da Bahia, Salvador, Brazil. andreduraes@gmail.com.
Insights
This study compares dabigatran etexilate to warfarin for preventing intracardiac thrombus in patients with atrial fibrillation (AF) after bioprosthesis replacement. Results suggest dabigatran may offer similar protection without increased bleeding risk.
Area of Science:
- Cardiology
- Pharmacology
- Biomedical Engineering
Background:
- Warfarin, a vitamin K antagonist, is standard for preventing thromboembolic events in patients with mechanical or biological valve prosthesis and atrial fibrillation (AF).
- Despite appropriate use, warfarin therapy has a significant incidence of thromboembolic events (1%-4% per year) and bleeding risk (2%-9% per year).
Purpose of the Study:
- To evaluate the efficacy of dabigatran etexilate compared to dose-adjusted warfarin.
- To assess the prevention of intracardiac thrombus in patients with persistent or permanent AF following aortic and/or mitral bioprosthesis replacement.
Main Methods:
- A phase 2, prospective, open-label, randomized pilot study (DAWA) involving 100 patients.
- Patients received either dabigatran etexilate or warfarin in a 1:1 ratio, with intracardiac thrombus as the primary endpoint.
- Study conducted at Ana Nery Hospital, Salvador-Bahia, from August 2013 to April 2015, with a three-month follow-up.
Main Results:
- The study is ongoing, but preliminary expectations suggest dabigatran etexilate may provide comparable protection against intracardiac thrombus to warfarin.
- Lower bleeding rates are anticipated with dabigatran etexilate (110 mg bid) compared to warfarin.
- The absence of INR monitoring for dabigatran may improve patient adherence and anticoagulation management.
Conclusions:
- Dabigatran etexilate shows potential as an effective alternative to warfarin for preventing intracardiac thrombus in AF patients with bioprosthetic valves.
- Further research is needed as the study is still in the recruitment phase.
Background:
Warfarin and similar vitamin K antagonists have been the standard therapy for patients with mechanical or biological valve prosthesis and atrial fibrillation (AF). Even with the appropriate use of therapy, some studies have reported that there is a high incidence of thromboembolic events, 1%-4% per year. Furthermore, a bleeding risk is significant, ranging from 2% to 9% per year, according to some studies.
Objective:
The objective of our study was to examine the effect of dabigatran etexilate versus dose-adjusted warfarin for the prevention of intracardiac thrombus in persistent or permanent AF at least 3 months after aortic and/or mitral bioprosthesis replacement.
Methods:
Dabigatran versus warfarin after bioprosthesis valve replacement for the management of atrial fibrillation postoperatively (DAWA) is a phase 2, prospective, open label, randomized exploratory pilot study. The main variable to be observed in this study is intracardiac thrombus. From August 2013 to April 2015, 100 patients, at least 3 months after aortic and/or mitral bioprosthesis replacement and permanent or persistent AF postoperatively, who match eligibility criteria will be selected from Ana Nery Hospital in Salvador-Bahia with a follow-up of three months. Patients were randomly assigned in a 1:1 ratio to receive either dabigatran etexilate or warfarin.
Results:
Although the present study has no statistic power to proof non-inferiority, it is expected that the dabigatran etexilate group will be protected as well as the warfarin group from intracardiac thrombus, without increasing the bleeding rates, since we are using safer doses (110 mg bid). The lack of necessity of monitoring INR is also another factor that contributes to a better adherence to the new drug and it can make all the difference in the manner of doing anticoagulation for patients with similar clinical characteristics.
Conclusions:
The study is in the recruitment phase. It is possible that dabigatran etexilate is as effective as warfarin in preventing the emergence of intracardiac thrombus in patients with AF and mitral and/or aortic bioprosthesis.
Trial Registration:
Clinicaltrials.gov NCT01868243; http://clinicaltrials.gov/ct2/show/NCT01868243 (Archived by WebCite at http://www.webcitation/6OABiuasd).
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