title: Prospective randomized evaluation of the watchman left atrial appendage closure device in patients with atrial fibrillation versus long-term warfarin therapy: The PREVAIL trial.
abstract: OBJECTIVE
  Assessing the safety and effectiveness of left atrial appendage (LAA) (pouch found in the upper chambers of the heart) occlusion, using the Watchman device compared to long term warfarin therapy (drug that reduces clot formation), in preventing the risk of stroke in patients with atrial fibrillation (most common type of irregular heart beat). 90% of strokes in atrial fibrillation arise from clots forming in this pouch. By mechanically blocking it using the device less clots are suggested to be formed. This is an alternative to taking warfarin especially in patients who cannot take it.
  
  
  METHODS
  50 sites in the United States enrolled 407 participants. After being randomly allocated, the device group had 269 participants and warfarin group (comparator)had 138 participants.
  
  
  METHODS
  Patients with atrial fibrillation and at high risk of stroke were randomly allocated a group after they were deemed eligible. Patients in the device group had to take warfarin and aspirin for 45days till the complete closure of the LAA. The oral anticoagulant was followed by dual antiplatelet therapy until 6months and then ASA. Patients in the warfarin group have to take it for life and were continually monitored. The study ran for 26months.
  
  
  METHODS
  The trial assessed the rate of adverse events using three endpoints:
  
  
  RESULTS
  The PREVAIL trial was not designed to show superiority, but non-inferiority. It met the safety endpoint and one efficacy endpoint for the watchman device compared to long term warfarin for overall efficacy of the device. The results established that LAA occlusion is not worse than warfarin intake for the prevention of stroke more than 1week after randomization. Compared to previous trials, the safety of the device has also improved.
  
  
  CONCLUSIONS
  LAA occlusion is a reasonable alternative to chronic warfarin therapy in stroke prevention for patients with atrial fibrillation.
authors.affiliation: Barts and The London School of Medicine and Dentistry, London, UK. Electronic address: d.r.belgaid@smd13.qmul.ac.uk.
authors.forename: Djouhar Roufeida
authors.initials: DR
authors.lastname: Belgaid
authors.affiliation: Barts and The London School of Medicine and Dentistry, London, UK.
authors.forename: Zara
authors.initials: Z
authors.lastname: Khan
authors.affiliation: Barts and The London School of Medicine and Dentistry, London, UK.
authors.forename: Mariam
authors.initials: M
authors.lastname: Zaidi
authors.affiliation: William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, QMUL, Charterhouse Square, London EC1M 6BQ, UK.
authors.forename: Adrian
authors.initials: A
authors.lastname: Hobbs
mesh_terms: D000925:Anticoagulants / Q000008:administration & dosage*; D020517:Atrial Appendage / Q000000981:diagnostic imaging / Q000187:drug effects*; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging / Q000517:prevention & control*; D006801:Humans; D011446:Prospective Studies; D011474:Prosthesis Design / Q000295:instrumentation / Q000592:standards; D016032:Randomized Controlled Trials as Topic / Q000379:methods*; D060205:Therapeutic Occlusion / Q000295:instrumentation* / Q000592:standards; D016896:Treatment Outcome; D014859:Warfarin / Q000008:administration & dosage*
chemical_list: D000925:Anticoagulants; D014859:Warfarin