Atrial fibrillation (AF) is nowadays the most common human arrhythmia and it is considered a marker of an increased risk of embolic stroke. It is known that 99% of AF-related thrombi are
generated in the left atrial appendage (LAA), an anatomical structure located within the left atrium
(LA). Left atrial appendage occlusion (LAAO) has become a good alternative for nonvalvular AF
patients with contraindications to anticoagulants. However, there is a non-negligible number of
device-related thrombus ...
Atrial fibrillation (AF) is nowadays the most common human arrhythmia and it is considered a marker of an increased risk of embolic stroke. It is known that 99% of AF-related thrombi are
generated in the left atrial appendage (LAA), an anatomical structure located within the left atrium
(LA). Left atrial appendage occlusion (LAAO) has become a good alternative for nonvalvular AF
patients with contraindications to anticoagulants. However, there is a non-negligible number of
device-related thrombus (DRT) events, created next to the device surface. In silico fluid simulations
can be a powerful tool to better understand the relation between LA anatomy, haemodynamics,
and the process of thrombus formation. Despite the increasing literature in LA fluid modelling,
a consensus has not been reached yet in the community on the optimal modelling choices and
boundary conditions for generating realistic simulations. In this line, we have performed a sensitivity
analysis of several boundary conditions scenarios, varying inlet/outlet and LA wall movement
configurations, using patient-specific imaging data of six LAAO patients (three of them with DRT
at follow-up). Mesh and cardiac cycle convergence were also analysed. The boundary conditions
scenario that better predicted DRT cases had echocardiography-based velocities at the mitral valve
outlet, a generic pressure wave from an AF patient at the pulmonary vein inlets, and a dynamic
mesh approach for LA wall deformation, emphasizing the need for patient-specific data for realistic
simulations. The obtained promising results need to be further validated with larger cohorts, ideally
with ground truth data, but they already offer unique insights on thrombogenic risk in the left atria.
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