Left Atrial Appendage Occlusion Study II

Phase III Pilot Study - Left Atrial Appendage Occlusion Study

A pilot, multicentre randomized controlled study of surgical left atrial occlusion (LAA) in 50 patients with atrial fibrillation/flutter undergoing cardiac surgery requiring cardiopulmonary bypass with additional risk factors for late stroke.

Patients will be enrolled and randomized to undergo LAA exclusion and aspirin therapy or best medical therapy as per guidelines.

Main research questions:

1. Can successful occlusion of the LAA be safely achieved by cut and sew or stapler techniques?
2. In patients with atrial fibrillation with 2 or more risk factors for stroke, will removal of the left atrial appendage (LAA) and aspirin therapy reduce the risk of systemic embolic events and major bleeding compared to warfarin?

The number one cause of disability and the 3rd leading cause of death in patients with atrial fibrillation (AF) is stroke. Echocardiographic studies suggest that the predominant source of stroke in AF is the left atrial appendage (LAA). At present, there are no sufficiently powered trials to answer whether removal of the LAA can reduce the risk of systemic embolic events.

LAAOS pilot study will recruit 50 participants undergoing open-heart surgery in 5 Canadian academic cardiac surgery centers. The study will inform the feasibility of conducting a large RCT and will provide information of the efficacy and safety of appendage occlusion technique. From this study we envision a a large international randomized controlled trial (LAAOS II) to determine the impact of left atrial appendage occlusion on the composite outcome of stroke and non-central nervous system systemic embolic events in at risk patients with atrial fibrillation undergoing cardiac surgery.

Inclusion Criteria:

• Adult patients undergoing any cardiac surgical procedure with the use of cardiopulmonary bypass

• A history of ECG-documented atrial fibrillation with prior stroke or TIA, or at least two of the following risk factors:

  • age => 65 years
  • hypertension
  • diabetes mellitus, or
  • heart failure/left ventricular ejection fraction < 50%

Exclusion Criteria:

• Patients in whom surgical AF ablation (MAZE or otherwise) is planned
• Planned "off-pump" surgery
• Planned implantation of a mechanical valve
• Heart transplant, complex congenital heart surgery, and ventricular assist device insertion, reoperation