Impact of Left Atrial Appendage Occluder Position on Thrombogenic Risk: A Computational Simulation Study in Atrial Fibrillation Patients

Atrial fibrillation is the most common cardiac arrhythmia and is associated with a significantly increased risk of stroke, mainly due to thrombus formation in the left atrial appendage. Oral anticoagulant therapy represents the standard treatment for stroke prevention; however, in patients with contraindications, percutaneous left atrial appendage occlusion offers an effective alternative. Despite its clinical adoption, the procedure carries risks such as peri-device leaks and device-related thrombus, which occur in up to 7% of patients and are influenced by incomplete endothelialization and thrombogenic hemodynamic patterns. Anatomical variability of the LAA plays a key role in device selection and positioning, directly impacting procedural success and thrombotic risk. Standard imaging modalities, such as transesophageal echocardiography and fluoroscopy, are commonly used for pre-procedural planning, while computed tomography allows for detailed three-dimensional reconstructions. However, imaging alone does not fully capture blood flow behavior, which is critical in assessing postoperative thrombotic risk. Computational fluid dynamics simulations represent a promising patient-specific tool to investigate the hemodynamic consequences of device implantation. This study evaluates, through CFD simulations on patient-specific models, the influence of device type and positioning on blood flow patterns within the LAA. Two configurations were analyzed: the Amplatzer Amulet and the Watchman FLX. The analysis focused on flow velocity distribution, recirculation zones, and particle washout, as key indicators of thrombus formation risk. By comparing these device configurations, the study aims to identify implantation strategies that optimize flow dynamics, minimize thrombogenic risk, and improve procedural outcomes. The findings provide insights for tailoring LAAO procedures to individual patients, contributing to safer and more effective stroke prevention in AF.