Incidence and Determinants of Incomplete Left Atrial Appendage Occlusion During Robot-Assisted Mitral Valve Surgery

BACKGROUND Epicardial clipping devices are used for left atrial appendage (LAA) occlusion to prevent stroke.However, the rate and determinants of incomplete occlusion have not been determined.We clarified the rate of incomplete LAA occlusion and identified its morphologic determinants during robot-assisted minimally invasive surgery.METHODS Between 2018 and 2024, 129 patients underwent LAA occlusion with a clip device during robot-assisted mitral surgery.Of them, 45 patients (median age, 67 years; 58% male) who underwent postoperative contrast-enhanced computed tomography were enrolled.The incidence of incomplete LAA occlusion (defined as contrast material detected in the LAA with stumps of >10 mm) was determined, with focus on the difference between the LAA ostium diameter and the size of the clip device. RESULTSThe median LAA ostium diameter at baseline was 29.3 mm (26.8-32.1 mm).The incomplete LAA occlusion was observed in 12 patients (26.7%), in 2 of whom large thrombi were demonstrated in the LAA.The rate of incomplete occlusion was significantly higher for cases in which the difference between the LAA ostium diameter and the size of the clip device was <10 mm (33.3% vs 0%; P < .026). CONCLUSIONSIn selected patients who underwent LAA occlusion with a clip device during robotassisted mitral surgery, approximately one-fourth showed incomplete LAA occlusion, presumably related to LAA morphology and clip device size.Although there might be some technical challenges of LAA occlusion through the transverse sinus approach, preoperative contrast-enhanced computed tomography assessment of the LAA could be employed to facilitate proper clip device selection and to reduce the risk of incomplete occlusion.