Left atrial appendage remodeling following percutaneous closure with WATCHMAN 2.5 and FLX: insights from the WATCH-DUAL registry

Abstract

Background Percutaneous left atrial appendage closure (LAAC) has emerged as a valid option for prevention of thromboembolic events in patients with non-valvular atrial fibrillation and contraindications for oral anticoagulation. The most recent devices have been created to improve the intervention efficiency and to allow the procedure in a wider range of anatomies. The new-generation Watchman FLX (WMFLX) features a new design but its in vivo performances have not been compared to the previous WATCHMAN 2.5 (WM2.5) prosthesis. Hence, the data regarding conformability, compression and device-related LAA remodeling are scarce. Purpose To compare the anatomical results of WM2.5 and WMFLX implantation and impact on LAA dimensions. Methods This study included LAAC patients from the WATCH-DUAL registry who benefited from a pre- and post-intervention CT scan. The WATCH-DUAL study was a dual center observational study including all the LAAC procedures prospectively collected in local registries from two high-volume centres between November 2017 and December 2020. The LAA and device dimensions were measured in a centralized core lab by 3D CT scan reconstruction methods, focusing on the device landing zone (LZ/defined as the cross section of the appendage that was perpendicular to its axis and connected the circumflex artery to a point 1 to 2 cm inside the LAA). Results This analysis included n=107 patients (n=58 WMFLX, n=49 WM2.5). The patients clinical profiles didn't differ, except for a higher proportion of coronary artery disease in WM2.5 group. The LAA dimensions were comparable between groups. There was a significantly higher proportion of chickenwing shapes in the WMFLX patients. The mean device baseline diameter was in the WMFLX compared to the WM2.5 patients (28.8±0.5 vs. 25.7±0.4 mm, p<0.001). The median delay for CT control was 48 (43–62) days. The LZ area (451 (363–521) vs. 366 (260–459) mm2, p<0.001) and minimal diameter (23.0 (20.7–24.8) vs. 18.7 (15.9–21.8) mm, p<0.001) significantly increased after implantation among patients. The LZ area increase absolute value and percentage were 101 (18–151) mm2 and 28 (4–54) % respectively. The LZ dimensions increase was more pronounced in the WMFLX group: these patients exhibited post LAAC larger LZ area and dimensions compared to the WM2.5 cases. The LAA eccentricity was reduced after implantation: the ratio LZ maximal/LZ minimal diameter significantly decreased for all patients (r=1.28 (1.18–1.40) vs. 1.06 (1.05–1.09), p<0.001). Comparable results were observed in WMFLX and WM2.5 patients. A multivariable regression analysis demonstrated that baseline LAA length, baseline LZ eccentricity and WM FLX use were independent predictors of LAA remodeling/dimensions increase. Conclusion LAA dimensions increased over time at the site of WM prosthesis implantation suggesting a local positive appendage remodeling after procedure. This phenomenon appears to be more pronounced with the WMFLX device. FUNDunding Acknowledgement Type of funding sources: None.

Left atrial appendage occlusion: On the need of a numerical model to simulate the implant procedure

“…Fixed the device's size (hence the ), DO is inversely related to : the bigger is, the smaller DO becomes. Clinical studies outline how an over‐compression of the device, attributable to an excessive oversize, may lead to DP towards the left atrium with subsequent risks of device‐related thrombosis 34,35 Ostium eccentricity: the eccentricity of the LAA ostium is a feature that may lead to eventual post‐procedural peri‐device leaks, given the mismatch between an almost circular device and an irregular‐shaped ostium.…”