Evaluation of a novel device for left atrial appendage exclusion: The second-generation atrial exclusion device

Background: The left atrial appendage is a frequent source of thromboemboli in patients with atrial fibrillation. Exclusion of the left atrial appendage may reduce the risk of stroke in patients with atrial fibrillation. The atrial exclusion device, previously developed to perform left atrial appendage exclusion on a beating heart, was modified to accommodate different anatomic patterns of the human left atrial appendage and to ensure uniform pressure and occlusion. The purpose of this study was to evaluate this second-generation atrial exclusion device during a midterm period in a canine model. Methods: Ten mongrel dogs ( mean weight 28.9 +/- 4.6 kg) were used in this study. The atrial exclusion device, constructed from two parallel and rigid titanium tubes and two nitinol springs with a knit-braided polyester fabric, was implanted at the base of the left atrial appendage through a left thoracotomy on a beating heart using a specially designed delivery tool. Dogs were evaluated at 30 days ( n = 4) and 90 days ( n = 6) by epicardial echocardiography, left atrial and coronary angiography, gross pathology, and histologic inspection. Results: Device implantation was performed without complications in all dogs. Complete left atrial appendage exclusion without device migration or hemodynamic instability was confirmed, and there was no damage to the left circumflex artery or pulmonary artery. Macroscopic and microscopic assessments revealed favorable biocompatibility during midterm follow-up. Conclusion: The atrial exclusion device enabled rapid, reliable, and safe exclusion of the left atrial appendage. Clinical application may provide a new therapeutic option for reducing the risk of stroke in patients with atrial fibrillation.