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Primary DiseasePhase 2/3DAWANCT01868243

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

A Phase 2/3 study testing Dabigatran and Warfarin in people with Primary Disease, run by Hospital Ana Nery at 1 site in Brazil.

Terminated

Stopped early. The study ended before it was planned to and will not resume.

Official record
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Trial summary

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. Read more about this study

Who is it for?
Ages 18 to 64 years
Conditions the study is for
Primary Disease
What is being tested?
Dabigatran and Warfarin
Could I receive a placebo?
No, everyone receives an active treatment
How many people
27 participants
Where
1 siteBrazil
Study dates
Aug 2013to Oct 2014
Phase
Phase 2/3
Are there results?
Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 to 64 years
  • All sexes
  • No healthy volunteers
  • Adult

Who may be able to join

  • 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

Who cannot join

  • 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)
Show all 11Show fewer
  • 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

Trial locations and contacts

1 site in 1 country.

Brazil1 site

  • Hospital Ana Nery

    Salvador, Estado de Bahia, 40320010

Other trials in Brazil

About this study

Official title: 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.

Read the 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.

Conditions
Primary Disease
Being tested
Dabigatran, Warfarin
Keywords
Atrial Fibrillation, Bioprosthesis, Stroke, Dabigatran, Warfarin
Medical subject headings
Atrial Fibrillation, Stroke

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • DabigatranDrug

    Also called Pradaxa® (dabigatran etexilate) 110mg twice daily

    Group 1 - Dabigatran 110 mg (50 patients)

  • WarfarinDrug

    Also called Warfarin adjusted-dose

    Warfarin adjusted-dose

Study groups in NCT01868243
Study groupRoleWhat they receive
DabigatranExperimentalDabigatran 110 mg BID
Receives: Drug: Dabigatran
WarfarinActive comparatorWarfarin adjusted-dose
Receives: Drug: Warfarin

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Intracardiac Thrombus

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

    Measured: 90 days

Secondary outcomes (1)

  1. Spontaneous Echo Contrast

    Spontaneous Echo Contrast showed in Transesophageal echocardiography

    Measured: 90 days

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted4 Jun 2013 (estimated)
  2. Study startAug 2013
  3. Primary completionSep 2014
  4. Study completionOct 2014

Why it stopped: because a significant decrease of viable candidates for the study.

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 2/3
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Masking
None (open label)
Enrolment
27 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT01868243
Sponsor's protocol ID
DAWA2013
Acronym
DAWA
Status last verified
Sep 2015
First submitted
28 May 2013
Last updated
9 Oct 2015
Data monitoring committee
Yes

Publications

  • Nkomo VT, Gardin JM, Skelton TN, Gottdiener JS, Scott CG, Enriquez-Sarano M. Burden of valvular heart diseases: a population-based study. Lancet. 2006 Sep 16;368(9540):1005-11. doi: 10.1016/S0140-6736(06)69208-8.

    PubMed 16980116

  • Carapetis JR, Steer AC, Mulholland EK, Weber M. The global burden of group A streptococcal diseases. Lancet Infect Dis. 2005 Nov;5(11):685-94. doi: 10.1016/S1473-3099(05)70267-X.

    PubMed 16253886

  • Sun JC, Davidson MJ, Lamy A, Eikelboom JW. Antithrombotic management of patients with prosthetic heart valves: current evidence and future trends. Lancet. 2009 Aug 15;374(9689):565-76. doi: 10.1016/S0140-6736(09)60780-7.

    PubMed 19683642

  • Heras M, Chesebro JH, Fuster V, Penny WJ, Grill DE, Bailey KR, Danielson GK, Orszulak TA, Pluth JR, Puga FJ, et al. High risk of thromboemboli early after bioprosthetic cardiac valve replacement. J Am Coll Cardiol. 1995 Apr;25(5):1111-9. doi: 10.1016/0735-1097(94)00563-6.

    PubMed 7897124

  • Connolly SJ, Ezekowitz MD, Yusuf S, Eikelboom J, Oldgren J, Parekh A, Pogue J, Reilly PA, Themeles E, Varrone J, Wang S, Alings M, Xavier D, Zhu J, Diaz R, Lewis BS, Darius H, Diener HC, Joyner CD, Wallentin L; RE-LY Steering Committee and Investigators. Dabigatran versus warfarin in patients with atrial fibrillation. N Engl J Med. 2009 Sep 17;361(12):1139-51. doi: 10.1056/NEJMoa0905561. Epub 2009 Aug 30.

    PubMed 19717844

  • Duraes AR, de Souza Roriz P, de Almeida Nunes B, Albuquerque FP, de Bulhoes FV, de Souza Fernandes AM, Aras R. Dabigatran Versus Warfarin After Bioprosthesis Valve Replacement for the Management of Atrial Fibrillation Postoperatively: DAWA Pilot Study. Drugs R D. 2016 Jun;16(2):149-54. doi: 10.1007/s40268-016-0124-1.

    PubMed 26892845

  • Duraes AR, Roriz PD, Bulhoes FV, Nunes BD, Muniz JQ, Neto IN, Fernandes AM, Reis FJ, Camara EJ, Junior ED, Segundo DTs, Silva FP, Aras R. Dabigatran versus warfarin after bioprosthesis valve replacement for the management of atrial fibrillation postoperatively: protocol. JMIR Res Protoc. 2014 Apr 1;3(2):e21. doi: 10.2196/resprot.3014.

    PubMed 24691436

Questions about this trial

What is this clinical trial studying?

A Phase 2/3 study testing Dabigatran and Warfarin in people with Primary Disease, run by Hospital Ana Nery at 1 site in Brazil.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 6 inclusion and 11 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: stopped early, as of the sponsor's last update on 9 Oct 2015. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in Brazil. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this combined phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 9 Oct 2015). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Intracardiac Thrombus (time frame: 90 days). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT01868243, which also lists 7 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 9 Oct 2015; AzTrials last refreshed its copy on 6 Nov 2026.

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