Transfabric Leaks After Percutaneous Left Atrial Appendage Occlusion Procedures with the WATCHMAN FLX Device.

Background: Cardiac computed tomography imaging with contrast is being used increasingly to image left atrial appendage occlusion (LAAO) devices. Contrast flow across a device, also known as a transfabric leak (TFL), may indicate a lack of complete LAAO-device endothelialization. The data on the rate, predictors, and clinical events associated with TFL are limited. Methods: All patients who underwent an LAAO-device implantation with a WATCHMAN FLX device and received a postimplantation computed tomography scan were included in this single-centre retrospective cohort study. Patients were classified as either having or not having a TFL, according to 3 currently proposed definitions of TFL. Clinical and procedural differences between the 2 groups were determined. An exploratory univariate logistic regression model to evaluate predictors of TFL was constructed. Results: A total of 56 individuals were included in the cohort. The rate of TFL varied from 27% to 52%, depending on the radiographic definition employed. No clinically important patient or procedural characteristics were noted between the groups with vs without TFL. No predictors of TFL were identified. Six deaths and one stroke occurred during a median follow-up period of 673 days. Conclusions: TFLs occur commonly post-LAAO procedures, suggesting that complete endothelialization of LAAO devices in humans may not be similar to that reported in animal models. Additional study into the best imaging approach to identify TFLs, and clinical events associated with TFLs, is necessary to clarify the significance of TFLs.