Role of Aortic Geometry on Stroke Propensity based on Simulations of Patient-Specific Models.

Stroke is a life threatening event that is expected to more than double over the next 40 years. Atrial fibrillation (AF) has been reported as a strong independent risk factor for stroke. We have previously shown that a hemodynamic perturbation by AF or reduced cardiac output and cycle length may have a significant impact on clot trajectory and thus embolic stroke propensity through the left common carotid artery using an idealized aortic arch model. Here, we show the dependence of flow patterns and hence stroke propensity on geometry of patient-specific aortas. We performed computational fluid dynamics (CFD) simulations to determine the variations of AF-induced stroke propensity over various image-based patient-dependent aorta models. The results demonstrated that curvature pattern of aorta can play a determinant role in AF-induced stroke propensity alteration. Specifically, it was shown that the hemodynamic perturbation by AF considered led to substantial increase in stroke propensity (i.e., 2.5~3.8 fold elevation) for lower curvature angle <90° while the changes in stroke propensity by AF are negligible for higher curvature angle >90°. The present simulations suggest that aortic arch curvature is an important risk factor for embolic stroke which should be tested in future clinical trials.