Comparison of Watchman Flx and Flx Pro Using Cardiac Computed Tomography Angiography after Left Atrial Appendage Occlusion

Document Type

Conference Proceeding

Publication Date

7-1-2026

Publication Title

J Cardiovasc Comput Tomogr

Keywords

adult, aged, atrial fibrillation, benchmarking, blood clotting, cerebrovascular accident, CHA2DS2-VASc score, clinical outcome, coating (procedure), computed tomographic angiography, computer assisted tomography, conference abstract, controlled study, device comparison, drug combination, female, follow up, heart atrium appendage, heart left atrium, human, left atrial appendage closure, left atrial appendage closure device, major clinical study, male, middle aged, peridevice leak, retrospective study, transesophageal echocardiography

Abstract

Introduction: Left atrial appendage occlusion (LAAO) with the Watchman FLX device (FLX) is increasingly used to reduce stroke risk in patients with atrial fibrillation. The Watchman FLX Pro (FLX Pro) is a newer iteration incorporating a surface coating designed to reduce thrombus formation and promote endothelialization. Cardiac computed tomography angiography (CCTA) has emerged as an important modality for post-LAAO evaluation of procedural success. Compared with transesophageal echocardiography, CCTA has higher sensitivity for detecting peri-device leak and residual appendage opacification, allowing more nuanced assessment of device performance following implantation. Methods: We retrospectively evaluated 81 consecutive patients (n=81, 47% women) undergoing LAAO with the FLX and FLX Pro devices who underwent routine 45-day follow-up CCTA. Of the 81 patients, average age for FLX patients were 76.8±6.49 and FLX PRO were 77.1±7.52, p=0.84. Studies were evaluated for device seal by assessing device position, compression at the device neck using average device dimension, presence of peri-device leak, and leak around device fabric. Average Hounsfield units (HU) were measured within the highest attenuation region of the device, left atrial appendage, and adjacent left atrium. Markers of device thrombus included HU <100 and an LAA-to-LA attenuation ratio <0.25. Final grading of device seal was performed using an integrative approach incorporating both quantitative and qualitative parameters. Results: A total of 81 patients were evaluated (FLX n=40, 49.4%; FLX Pro n=41, 50.6%). Baseline CHA2DS2-VASc score was 5.23±1.51 for FLX patients and 4.05±1.3, p<0.001 for FLX Pro patients. Integrative evaluation of LAAO seal demonstrated that Watchman FLX Pro achieved a higher rate of complete appendage occlusion compared with FLX (33 41, 80.5% vs 14 40, 35%, p<0.001). Quantitatively, LAA LA attenuation ratio <0.25 occurred more frequently in the FLX Pro cohort (25 41, 61% vs 17 40, 42.5%, p=0.06). Both devices demonstrated similar compression at the device neck (FLX Pro 10.5% vs FLX 10.7%, p=0.85). Conclusions: Cardiac computed tomography demonstrates higher rates of complete appendage occlusion with the Watchman FLX Pro compared with the Watchman FLX despite similar levels of compression. This suggests that design modifications of the FLX Pro may improve appendage sealing. Prior CCTA studies of LAAO have demonstrated frequent residual appendage opacification and further study is needed to determine whether imaging-based metrics of occlusion may inform device design and provide mechanistic insight into clinical outcomes.

Volume

20

Issue

4

First Page

S107

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