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

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ClinicalTrials.gov Identifier: NCT01868243
Recruitment Status : Terminated (because a significant decrease of viable candidates for the study.)
First Posted : June 4, 2013
Results First Posted : October 9, 2015
Last Update Posted : October 9, 2015
Information provided by (Responsible Party):
Andre Duraes, PhD, Hospital Ana Nery

May 28, 2013
June 4, 2013
June 24, 2015
October 9, 2015
October 9, 2015
August 2013
September 2014   (Final data collection date for primary outcome measure)
Intracardiac Thrombus [ Time Frame: 90 days ]
The primary endpoint was the detection of intracardiac thrombus in TEE at the end of follow-up (90 days).
The primary efficacy end point was the composite of stroke (ischemic or hemorrhagic) and systemic embolism. [ Time Frame: 1 year ]
Complete list of historical versions of study NCT01868243 on ClinicalTrials.gov Archive Site
Spontaneous Echo Contrast [ Time Frame: 90 days ]
Spontaneous Echo Contrast showed in Transesophageal echocardiography
A individual occurrence of stroke, systemic embolism, or death from all causes. [ Time Frame: 6 months ]
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Dabigatran Versus Warfarin After Mitral and/or Aortic Bioprosthesis Replacement and Atrial Fibrillation Postoperatively
Dabigatran Versus Warfarin After Mitral and Aortic Bioprosthesis Replacement for the Management of Atrial Fibrillation Postoperatively: Pilot Study
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.

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.

Phase 2
Phase 3
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Primary Disease
  • Drug: Dabigatran
    Group 1 - Dabigatran 110 mg (50 patients)
    Other Name: Pradaxa® (dabigatran etexilate) 110mg twice daily
  • Drug: Warfarin
    Warfarin adjusted-dose
    Other Name: Warfarin adjusted-dose
  • Experimental: Dabigatran
    Dabigatran 110 mg BID
    Intervention: Drug: Dabigatran
  • Active Comparator: Warfarin
    Warfarin adjusted-dose
    Intervention: Drug: Warfarin

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
October 2014
September 2014   (Final data collection date for primary outcome measure)

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
Sexes Eligible for Study: All
18 Years to 64 Years   (Adult)
Contact information is only displayed when the study is recruiting subjects
Not Provided
Not Provided
Andre Duraes, PhD, Hospital Ana Nery
Hospital Ana Nery
Not Provided
Principal Investigator: Andre R Duraes, Professor Hospital Ana Nery
Hospital Ana Nery
September 2015

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP