Dabigatran Versus Warfarin After Mitral and/or Aortic Bioprosthesis Replacement and Atrial Fibrillation Postoperatively (DAWA)

This study has been terminated.
(because a significant decrease of viable candidates for the study.)
Information provided by (Responsible Party):
Andre Duraes, PhD, Hospital Ana Nery
ClinicalTrials.gov Identifier:
First received: May 28, 2013
Last updated: September 14, 2015
Last verified: September 2015
DAWA is a phase 2, prospective, open-label, randomized, pilot study. The main variable to be observed in this study is intracardiac thrombus. There are no formal primary or secondary clinical efficacy or safety outcomes because it is a pilot study.

Condition Intervention Phase
Primary Disease
Drug: Dabigatran
Drug: Warfarin
Phase 2
Phase 3

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: Dabigatran Versus Warfarin After Mitral and Aortic Bioprosthesis Replacement for the Management of Atrial Fibrillation Postoperatively: Pilot Study

Resource links provided by NLM:

Further study details as provided by Hospital Ana Nery:

Primary Outcome Measures:
  • Intracardiac Thrombus [ Time Frame: 90 days ] [ Designated as safety issue: No ]
    The primary endpoint was the detection of intracardiac thrombus in TEE at the end of follow-up (90 days).

Secondary Outcome Measures:
  • Spontaneous Echo Contrast [ Time Frame: 90 days ] [ Designated as safety issue: No ]
    Spontaneous Echo Contrast showed in Transesophageal echocardiography

Enrollment: 27
Study Start Date: August 2013
Study Completion Date: October 2014
Primary Completion Date: September 2014 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Dabigatran
Dabigatran 110 mg BID
Drug: Dabigatran
Group 1 - Dabigatran 110 mg (50 patients)
Other Name: Pradaxa® (dabigatran etexilate) 110mg twice daily
Active Comparator: Warfarin
Warfarin adjusted-dose
Drug: Warfarin
Warfarin adjusted-dose
Other Name: Warfarin adjusted-dose

Detailed Description:

Mortality and morbidity events (reversible ischemic neurological deficit, ischemic and hemorrhagic stroke, systemic embolism, any bleeding, prosthesis valve thrombosis and death) were evaluated in an exploratory manner. The details of the trial design have been previously described.8 The trial protocol was approved by the local ethics and research committee in the city of Salvador-Brazil, and written informed consent was obtained from all patients. An independent data and safety monitoring board closely monitored the trial. All the members contributed to the interpretation of the results, wrote the first version of the manuscript and approved all versions, made the decision to submit the manuscript for publication, and vouch for the accuracy and completeness of the data reported and the fidelity of this article to the study protocol.

Patients eligible for inclusion in the study were 18 to 64 years old, underwent mitral and/or aortic bioprosthesis valve replacement at least 3 months prior to entering the study and had documented AF postoperatively in addition to exclusion of atrial thrombus or valve prosthesis thrombosis by transesophageal echocardiography (TEE). Non-contrast brain computed tomography (CT) without hemorrhage or findings of acute cerebral infarction on the last 2 days of screening was also necessary.

Patients were randomly assigned to receive dabigatran or warfarin by a computer generated list of random numbers performed to 1:1 ratio between the groups. Following that, the allocation sequence was concealed from the researcher enrolling participants in sequentially numbered, opaque, black, sealed envelopes. After randomization, patients had study visits scheduled at 7 days (via telephone) and at 30 days (personally) with a monthly follow-up for 90 days. After this, non-contrast brain CT and TEE were repeated. The former was executed to document possible cerebral events with no clinical expression and the latter to analyze the incidence of intracardiac thrombi, new dense spontaneous echo contrast (SEC) or its resolution, in addition to thrombosis or dysfunction of valvular prosthesis.


Ages Eligible for Study:   18 Years to 64 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  1. Age from 18 to 64 years at entry
  2. Patients with mitral and/or aorthic valve bioprosthesis for at least 3 months postoperatively
  3. There is 12-lead electrocardiogram documented AF on the day of screening or randomization; or a 24-hour Holter electrocardiogram recording showing AF episodes postoperatively
  4. Brain computed tomography scan without hemorrhage or findings of acute cerebral infarction on the last 2 days of screening
  5. Exclusion of atrial thrombus or valve prosthesis thrombosis by transesophageal echocardiograph on the last 2 days of screening
  6. Written, informed consent

Exclusion Criteria:

  1. Previous hemorrhagic stroke
  2. Ischemic stroke in the last 6 months
  3. Severe renal impairment (creatinine clearance rates < 30 ml/min)
  4. Active liver disease (any etiology)
  5. Concomitant use of any antiplatelet (aspirin, clopidogrel, prasugrel, ticagrelor, ticlopidine, etc)
  6. Increased risk of bleeding (congenital or acquired)
  7. Uncontrolled hypertension
  8. Gastrointestinal hemorrhage within the past year
  9. Anemia (hemoglobin level <10 g/dL) or thrombocytopenia (platelet count < 100 × 109/L)
  10. Active infective endocarditis
  11. Pregnant or lactating women
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01868243

Hospital Ana Nery
Salvador, Bahia, Brazil, 40320010
Sponsors and Collaborators
Hospital Ana Nery
Principal Investigator: Andre R Duraes, Professor Hospital Ana Nery
  More Information

Responsible Party: Andre Duraes, PhD, Andre Rodrigues Duraes, Hospital Ana Nery
ClinicalTrials.gov Identifier: NCT01868243     History of Changes
Other Study ID Numbers: DAWA2013
Study First Received: May 28, 2013
Results First Received: June 24, 2015
Last Updated: September 14, 2015
Health Authority: Brazil: Ethics Committee

Keywords provided by Hospital Ana Nery:
Atrial Fibrillation

Additional relevant MeSH terms:
Atrial Fibrillation
Arrhythmias, Cardiac
Cardiovascular Diseases
Heart Diseases
Pathologic Processes
Enzyme Inhibitors
Hematologic Agents
Molecular Mechanisms of Pharmacological Action
Pharmacologic Actions
Protease Inhibitors
Serine Proteinase Inhibitors
Therapeutic Uses

ClinicalTrials.gov processed this record on November 30, 2015