Stroke risk evaluation for patients with atrial fibrillation: Insights from left atrial appendage with fluid-structure interaction analysis

The majority of cardioembolic strokes in patients with non-valvular atrial fibrillation (NVAF) are resulted from clot formation in the left atrial appendage (LAA). Current stroke risk stratification is based on the overall risks estimated from demographic and clinical profiles but not on individual anatomy or physiology. We aim to explore the differences in LAA morphological and hemodynamic parameters by comparing patients with and without a stroke history. Thirty-nine patients with persistent NVAF were included. Of these, 17 patients without a stroke history (non-stroke group) were compared with 22 patients with a history of stroke (stroke group). Their LAA geometric models were first reconstructed, and the morphological parameters were then measured. Furthermore, their LAA hemodynamic parameters were calculated by fluid-structure interaction analysis. Moreover, particle residual rates (PRR) and blood renewal rates (BRR) analyses were also employed to characterize the thrombogenesis dynamics. The results showed that compared to the non-stroke group, the stroke group had significant smaller LAA tortuosity and LAA orifice area, and significantly lower LAA orifice velocities (0.16 ± 0.10 vs 0.15 ± 0.06 cm/s; p = 0.044), but higher PRR (14.58 ± 9.43 vs 9.25 ± 4.67; p = 0.040) and BRR (52.41 ± 18.11 vs 38.36 ± 24.07; p = 0.044). These LAA morphological and hemodynamic parameters may be used to assess stroke risk in patients with NVAF.