Computational fluid dynamics to access the future risk of ascending aortic aneurysms

Abstract

Abstract Background A methodology to identify patients with ascending aortic aneurysm (AsAA) under high risk of aortic growth is not completely defined. Objective This research seeks to numerically characterize the blood flow and relate resulting stress distribution with AsAA growth. Methods Analytical, observational, single-center study in which a computational fluid dynamics (CFD) protocol was applied to aortic Computed Tomography Angiogram (CTA) images of patients with AsAA. Two (CTA) exams with at least one year of difference were obtained. From the CTA-gathered images, three-dimensional models were generated, and clinical data were registered. Study of velocity field and coherent structures (vortices) was performed aiming to relate them to aneurysm growth or non-growth, and thereafter to compare with the clinical data of these patients. Kolmogorov-Smirnov test was used to evaluate the normality distribution and for non-normal distribution, the non-parametric Wilcoxon signed-rank test was applied for comparisons of paired data of the aortic angles. Statistical significance was set at 5%. Results The incident jet in the aortic wall generated recirculation areas in the posterior region of the jet, inducing complex vortices formation, for the group that presented aneurysm growth, leading to an increase of the average pressure at the ascending aortic wall (Fig. 1), between exams. While for the group without aneurysm growth, the average pressure decreased. Conclusion This pilot study showed that CFD based upon CTA may in the near future be a tool to help identify flow patterns associated with AsAA remodeling process. Funding Acknowledgement Type of funding sources: None. Figure 1. Axialvelocity. Iso-surface-without-growthFigure 2. Isosurface of Q-criterion. Without growth