Left Atrial Appendage Occlusion Study (LAAOS): results of a randomized controlled pilot study of left atrial appendage occlusion during coronary bypass surgery in patients at risk for stroke.

AIM: This pilot study assessed the safety and efficacy of left atrial appendage (LAA) occlusion, performed at the time of coronary artery bypass grafting (CABG). METHODS AND RESULTS: At the time of CABG, 77 patients with risk factors for stroke were randomized to LAA occlusion or control. The LAA was occluded using sutures or a stapling device. Completeness of occlusion was assessed with transesophageal echocardiography. There were no significant differences in cardiopulmonary bypass duration, perioperative heart failure, atrial fibrillation, or bleeding between the 2 groups. During surgery, there were 9 appendage tears, all of which were repaired easily with sutures. Among patients having a postoperative transesophageal echocardiography, complete occlusion of the LAA was achieved in 45% (5/11) of cases using sutures and in 72% (24/33) using a stapler, P = .14. The rate of LAA occlusion by individual surgeons increased from 43% (9/21) to 87% (20/23) after performing 4 cases (P = .0001). After a mean follow-up of 13 +/- 7 months, 2.6% of patients had thromboembolic events. CONCLUSIONS: LAA occlusion at the time of CABG is safe. The rate of complete occlusion improves, to acceptable levels, with increased experience and the use of a stapling device. A large trial is needed to determine if LAA occlusion prevents stroke.