Hemodynamic differences caused by left atrial appendage modeling contours

Abstract

Comparing the hemodynamic parameters of thrombus-positive and thrombus-negative patients in the early stages of the disease (before thrombus formation occurs) can help predict atrial fibrillation-related thrombosis. However, most clinical images of thrombus-positive are of existing thrombus, and the presence of thrombi blurs the outline of the atrial appendage intima. Therefore, using the left atrial appendage (LAA) epicardial geometry for hemodynamic analysis has become a last resort. This study compares hemodynamic differences using the modeling contour of the inner and outer membranes of the LAA. The research results show the velocity and shear strain rate of the endocardial and epicardial geometries exhibit relative consistency. As for the parameters related to wall shear stress, the difference in time-averaged wall shear stress mainly occurs at the LAA entrance and does not affect the determination of thrombosis risk factors. The difference in the oscillatory shear index mainly occurs at the tip of LAA and the parts with larger curvature, which are seriously affected by geometry. The differences between endothelial cell activation potential (ECAP) and relative residence time (RRT) are concentrated at the tip of the LAA, but the maximum and minimum values are significantly different. After we exclude the top and bottom 5% of values, we believe that ECAP and RRT are reliable parameters. This investigation conducted both qualitative and quantitative assessments of the hemodynamic disparities between the endocardial and epicardial geometries. The findings offer valuable data reference for related research.