title: Rationale and design of the Left Atrial Appendage Occlusion Study (LAAOS) III.
abstract: BACKGROUND
  Occlusion of the left atrial appendage (LAA) is a promising approach to stroke prevention in atrial fibrillation (AF). However, evidence of its efficacy and safety to date is lacking. We herein describe the rationale and design of a definitive LAA occlusion trial in cardiac surgical patients with AF.
  
  
  METHODS
  We plan to randomize 4,700 patients with AF in whom on-pump cardiac surgical procedure is planned to undergo LAA occlusion or no LAA occlusion. The primary outcome is the first occurrence of stroke or systemic arterial embolism over a mean follow-up of four years. Other outcomes include total mortality, operative safety outcomes (chest tube output in the first post-operative 24 hours, rate of post-operative re-exploration for bleeding in the first 48 hours post-surgery and 30-day mortality), re-hospitalization for heart failure, major bleed, and myocardial infarction.
  
  
  RESULTS
  Left Atrial Appendage Occlusion Study (LAAOS) III is funded in a vanguard phase by the Canadian Institutes for Health Research (CIHR), the Canadian Network and Centre for Trials Internationally, and the McMaster University Surgical Associates. As of September 9, 2013, 162 patients have been recruited into the study.
  
  
  CONCLUSIONS
  LAAOS III will be the largest trial to explore the efficacy of LAA occlusion for stroke prevention. Its results will lead to a better understanding of stroke in AF and the safety and efficacy of surgical LAA occlusion.
authors: Department of Surgery, McMaster University, Hamilton, Canada ; ; Population Health Research Institute, McMaster University and Hamilton Health Sciences, Hamilton, Canada ;
authors: Richard
authors: R
authors: Whitlock
authors: Population Health Research Institute, McMaster University and Hamilton Health Sciences, Hamilton, Canada ; ; Department of Medicine, McMaster University, Hamilton, Canada ;
authors: Jeff
authors: J
authors: Healey
authors: Population Health Research Institute, McMaster University and Hamilton Health Sciences, Hamilton, Canada ;
authors: Jessica
authors: J
authors: Vincent
authors: Population Health Research Institute, McMaster University and Hamilton Health Sciences, Hamilton, Canada ;
authors: Kate
authors: K
authors: Brady
authors: Department of Surgery, McMaster University, Hamilton, Canada ; ; Department of Surgery, Southlake Regional Health Centre, Newmarket, Canada ;
authors: Kevin
authors: K
authors: Teoh
authors: Department of Surgery, Royal Melbourne Hospital, The University of Melbourne, Melbourne, Australia ;
authors: Alistair
authors: A
authors: Royse
authors: Department of Cardiothoracic Surgery, Princess Alexandra Hospital, University of Queensland, Brisbane, Australia ;
authors: Pallav
authors: P
authors: Shah
authors: Department of Cardiovascular Surgery, West China Hospital, Sichuan University, Chengdu, China ;
authors: Yingqiang
authors: Y
authors: Guo
authors: Department of Cardiology and Electrophysiology, Amphia Ziekenhuis, Breda, the Netherlands ;
authors: Marco
authors: M
authors: Alings
authors: Department of Cardiology, Medical Center Leeuwarden, Leeuwarden, the Netherlands ;
authors: Richard J
authors: RJ
authors: Folkeringa
authors: Division of Cardiac Surgery, Department of Emergency and Organ Transplant (DETO), University of Bari Aldo Moro, Bari, Italy ;
authors: Domenico
authors: D
authors: Paparella
authors: Department of Cardiology, Thoracic and Vascular Sciences, University of Padova, Padova, Italy ;
authors: Andrea
authors: A
authors: Colli
authors: Department of Surgery, University of Alberta, Edmonton, Canada ;
authors: Steven R
authors: SR
authors: Meyer
authors: Division of Cardiac Surgery, Dalhousie University, Halifax, Canada ;
authors: Jean-François
authors: JF
authors: Legare
authors: Centre de recherché Clinique Étienne-Lebel and Faculté de Médecine et des Sciences de la Santé, Univesité de Sherbrooke, Sherbrooke, Canada ;
authors: François
authors: F
authors: Lamontagne
authors: Department of Cardiac Surgery, Cardiovascular Clinic Bad Neustadt, Bad Neustadt, Germany ;
authors: Wilko
authors: W
authors: Reents
authors: Department of Cardiovascular Surgery, University of Giessen, Giessen, Germany.
authors: Andreas
authors: A
authors: Böning
authors: Population Health Research Institute, McMaster University and Hamilton Health Sciences, Hamilton, Canada ; ; Department of Medicine, McMaster University, Hamilton, Canada ;
authors: Stuart
authors: S
authors: Connolly
keywords: Left atrial appendage (LAA); occlusion; randomized trial; stroke