Assessment of Chronic Watchman Left Atrial Appendage Occlusion by Cardiac Computed Tomography Angiography

Abstract

Background: No studies have assessed longitudinal imaging of Watchman® left atrial appendage (LAA) occlusion beyond 12 months. We sought to assess appearances of the Watchman® device and completeness of LAA occlusion based on cardiac CT angiography in patients with chronic implants. Methods: A retrospective analysis of images from cardiac CT scans was performed in patients with a Watchman® implanted ≥2 years prior. Patients were imaged with Somatom Definition Flash CT scanners using 0.5–0.8mm axial slice thickness. Three-phase contrast left atrial imaging, or a CT Coronary Angiography protocol was employed. Image review was on InteleviewerPACS using axial reconstruction. Prior TOE imaging results were also analysed. Results: Twenty-four patients were imaged at a mean time of 44±13 months (range 24–72) post Watchman® implant. Watchman® device integrity was intact in all. Total occlusion of the LAA was identified in 11/24. Contrast opacification of the LAA distal to the device was noted in 13/24. Partial occlusion (non-opacification of portions of LAA) was noted in 7/13 varying from 25–90% volume. Comparison with prior TOE results found that in 16 patients with complete occlusion on TOE, 9 were later identified to have total occlusion and 7 had incomplete occlusion on CT. Of 7 patients with peri-device leak on TOE, 2 had total occlusion and 5 had incomplete occlusion on CT. Conclusions: In this study a 46% complete occlusion rate was found in chronic Watchman® implants based on Cardiac CT angiography. Early post-implant TOE imaging predicted long-term complete occlusion in only 58% of patients.