Pre-Procedural Imaging Modalities for Device Size Selection and Adaptive Nature of the Appendage in Patients Undergoing Percutaneous Left Atrial Appendage Closure

Background: This study aimed to compare different pre-procedural left atrial appendage (LAA) imaging modalities and analyze the anatomical adaptation of the LAA to the closure device at 3-month multi-slice computed tomography (MSCT). LAA closure device sizing is crucial to optimize immediate and long-term outcomes. Methods: Patients who underwent percutaneous LAA closure and had pre-procedural transesophageal echocardiography (TEE) and MSCT were identified. Devices used were Amulet(TM) (Abbott, USA), Watchman(TM,) and WatchmanFLX(TM) (Boston Scientific, USA). LAA ostium and landing zone were measured according to the instructions for use at 2D-TEE, as well as at MSCT and X-ray angiography. Post-procedural MSCT was used to assess LAA ellipticity and closure. Results: A total of 67 patients (44 Amulet(TM), 11 Watchman(TM), 12 WatchmanFLX(TM)) were included. Mean age was 74 +/- 7 years, CHA(2)DS(2)-VASc-score 3.0 +/- 1.6 and HAS-BLED-score 2.7 +/- 0.9. Bland-Altman analysis for the maximum LAA diameter at MSCT (CTmax) and TEE (TEEmax) showed a mean difference of +4.8 mm with a limit of agreement (LoA) of 9.6 mm (p < 0.01). Maximum LAA diameters at TEE (TEEmax) and X-ray angiography (XA(max)) showed a mean difference of +1.3 mm with LoA of 7.6 mm (p = 0.839). The mean difference between CTmean and TEEmax was +2.1 mm with LoA of 8.4 mm (p < 0.05). In addition, LAA ellipticity ratio decreased from 1.48 to 1.05 while overall LAA area only expanded 3% after device implantation. Conclusion: Of the three imaging modalities, MSCT provides the largest LAA measurements, followed by TEE and angiography. At follow-up MSCT, the elliptical LAA conforms to the circular shape of the closure device; however, overall LAA expansion is only minimal.