NUMERICAL SIMULATION OF HEMODYNAMICS IN AORTIC ANEURYSM AND COARCTATION OF THE AORTA: GEOMETRIC PARAMETERS EFFECT

Abstract

Cardiovascular diseases could affect children as they can affect elderly persons, they could be either acquired or congenital. The mortality rate from cardiovascular disease is higher in middle- and low-income countries compared to developed countries. In Algeria studies related to the management of cardiovascular diseases, the integration and the use of the newest technologies in the management of patients are still lacking. Computational fluid dynamic (CFD) methods present the advantage of giving the possibility to investigate non-invasively the cardiovascular disease and consequently present a good tool for clinicians. With the development of computing capabilities, high-performance calculations and medical imaging technologies, the use of computational fluid dynamic models in clinical use gained attention. Two diseases are studied in this thesis, namely abdominal aortic aneurysm AAA and aortic coarctation CoA. Using CFD the effect of asymmetry of AAA is studied. A detailed parametric analysis of flow dynamics using five virtual AAA models was performed. Flow behaviour and wall shear stress derivatives (time-averaged wall shear stress TAWSS, and oscillating shear stress OSI) were investigated. Secondly, an investigation of the co-localization and relationship between intraluminal thrombus ILT and WSS-based hemodynamic parameters (TAWSS, OSI, Transversal WSS transWSS, relative residence time RRT and Endothelial cell activation potential ECAP) was carried out. Computed Tomography CT data of three AAA patients were used. The model was validated against in-vitro data and a new approach was suggested to predict ILT deposition and growth based on WSS indexes in the thin and thick ILT areas. Finally, a workflow combining in-vivo (4D flow) and in-silico (CFD) data in the case of patients suffering from aortic coarctation (CoA) was presented. The verification and cross-validation of the two techniques confirm CFD’s robustness and its ability to mimic realistic 3D blood flow and wall parameters with high spatial and temporal resolution.