Left Atrial Appendage Occlusion Study - LAAOS III

Contribution To Literature:

The LAAOS III trial showed that on a background of anticoagulation, surgical left atrial appendage occlusion during cardiac surgery was beneficial.

Description:

The goal of the trial was to evaluate surgical left atrial appendage occlusion compared with no occlusion among patients with atrial fibrillation undergoing open heart surgery for another indication.

Study Design

  • Randomized
  • Parallel
  • Stratification

Patients with atrial fibrillation and elevated risk of stroke undergoing open heart surgery for another indication were randomized to surgical left atrial appendage occlusion (n = 2,379) versus no left atrial appendage occlusion (n = 2,391).

  • Total number of enrollees: 4,770
  • Duration of follow-up: 3.8 years
  • Mean patient age: 71 years
  • Percentage female: 32%
  • Percentage with diabetes: 32%

Inclusion criteria:

  • Patients undergoing cardiac surgery with cardiopulmonary bypass
  • Atrial fibrillation and CHA2DS2-VASc ≥2

Exclusion criteria:

  • Off-pump surgery
  • Mechanical valve implantation
  • Heart transplantation
  • Surgery for complex congenital heart disease
  • Isolated implantation of a left ventricular assist device
  • Previous surgery that involved opening the pericardium
  • Previous implantation of a left atrial appendage occlusion device

Other salient features/characteristics:

  • Isolated coronary artery bypass grafting: 20%
  • Isolated valve replacement: 23%
  • Other procedure: 57%
  • Bypass time: 119 minutes in the occlusion group vs. 113 minutes in the no occlusion group (p < 0.001)
  • Oral anticoagulation use at 3 years: 75% in the occlusion group vs. 78% in the no occlusion group

Principal Findings:

The primary outcome of ischemic stroke or systemic embolism at 3.8 years occurred in 4.8% of the occlusion group compared with 7.0% of the no occlusion group (p = 0.001).

  • Ischemic stroke or systemic embolism <30 days: 2.2% of the occlusion group compared with 2.7% of the no occlusion group (p = not significant)
  • Ischemic stroke or systemic embolism >30 days: 2.7% of the occlusion group compared with 4.6% of the no occlusion group (p = 0.001)

Secondary outcomes:

  • Ischemic stroke: 4.6% of the occlusion group compared with 6.9% of the no occlusion group (p < 0.05)
  • Reoperation for bleeding within 48 hours: 4.0% of the occlusion group compared with 4.0% of the no occlusion group

Interpretation:

Among patients with atrial fibrillation undergoing cardiac surgery, left atrial appendage occlusion was superior to no occlusion. Most patients remained on long-term anticoagulation therapy (75%). Left atrial appendage occlusion was associated with a significant reduction in ischemic stroke or systemic embolism at a mean of 3.8 years. More benefit was observed when the results were landmarked at 30 days versus <30 days. Major bleeding was similar between the treatment groups. The benefit of surgical left atrial appendage occlusion appeared to be additive to anticoagulation therapy; therefore, this trial does not support surgical left atrial appendage occlusion as a replacement to anticoagulation therapy.

References:

Whitlock RP, Belley-Cote EP, Paparella D, et al., on behalf of the LAAOS III Investigators. Left Atrial Appendage Occlusion During Cardiac Surgery to Prevent Stroke. N Engl J Med 2021;May 15:[Epub ahead of print].

Editorial: Page RL. The Closing Argument for Surgical Left Atrial Appendage Occlusion. N Engl J Med 2021;May 15:[Epub ahead of print].

Presented by Dr. Richard Whitlock at the American College of Cardiology Virtual Annual Scientific Session (ACC 2021), May 15, 2021.

Clinical Topics: Anticoagulation Management, Arrhythmias and Clinical EP, Cardiac Surgery, Cardiovascular Care Team, Geriatric Cardiology, Invasive Cardiovascular Angiography and Intervention, Prevention, Anticoagulation Management and Atrial Fibrillation, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Cardiac Surgery and Arrhythmias

Keywords: ACC21, ACC Annual Scientific Session, Anticoagulants, Arrhythmias, Cardiac, Atrial Appendage, Atrial Fibrillation, Brain Ischemia, Cardiac Surgical Procedures, Cardiopulmonary Bypass, Coronary Occlusion, Coronary Artery Bypass, Embolism, Geriatrics, Hemorrhage, Reoperation, Secondary Prevention, Stroke


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