Title

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
  • Phase

    Phase 2/Phase 3
  • Study Type

    Interventional
  • Indication/Condition

    Primary Disease
  • Study Participants

    27
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.
Study Started
Aug 31
2013
Primary Completion
Sep 30
2014
Study Completion
Oct 31
2014
Results Posted
Oct 09
2015
Estimate
Last Update
Oct 09
2015
Estimate

Drug Dabigatran

Group 1 - Dabigatran 110 mg (50 patients)

  • Other names: Pradaxa® (dabigatran etexilate) 110mg twice daily

Drug Warfarin

Warfarin adjusted-dose

  • Other names: Warfarin adjusted-dose

Dabigatran Experimental

Dabigatran 110 mg BID

Warfarin Active Comparator

Warfarin adjusted-dose

Criteria

Inclusion Criteria:

Age from 18 to 64 years at entry
Patients with mitral and/or aorthic valve bioprosthesis for at least 3 months postoperatively
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
Brain computed tomography scan without hemorrhage or findings of acute cerebral infarction on the last 2 days of screening
Exclusion of atrial thrombus or valve prosthesis thrombosis by transesophageal echocardiograph on the last 2 days of screening
Written, informed consent

Exclusion Criteria:

Previous hemorrhagic stroke
Ischemic stroke in the last 6 months
Severe renal impairment (creatinine clearance rates < 30 ml/min)
Active liver disease (any etiology)
Concomitant use of any antiplatelet (aspirin, clopidogrel, prasugrel, ticagrelor, ticlopidine, etc)
Increased risk of bleeding (congenital or acquired)
Uncontrolled hypertension
Gastrointestinal hemorrhage within the past year
Anemia (hemoglobin level <10 g/dL) or thrombocytopenia (platelet count < 100 × 109/L)
Active infective endocarditis
Pregnant or lactating women

Summary

Dabigatran

Warfarin

All Events

Event Type Organ System Event Term Dabigatran Warfarin

Intracardiac Thrombus

The primary endpoint was the detection of intracardiac thrombus in TEE at the end of follow-up (90 days).

Dabigatran

Warfarin

1.0
participants
95% Confidence Interval: 0.9 to 1.3

Spontaneous Echo Contrast

Spontaneous Echo Contrast showed in Transesophageal echocardiography

Dabigatran

2.0
participants

Warfarin

1.0
participants

Total

27
Participants

Age, Continuous

47
years (Mean)
Standard Deviation: 8

Region of Enrollment

Sex: Female, Male

Overall Study

Dabigatran

Warfarin

Drop/Withdrawal Reasons

Warfarin