Blood Flow in Dissected Aortas After Thoracic Endovascular Aortic Repair

Abstract

Every passing hour, 2050 people die due to cardiovascular diseases, a third of them occurring prematurely before the age of 70. An aortic dissection is a condition where a sudden tear in the aortic wall forces blood to enter between the layers of the wall, subsequently splitting the wall and creating a new channel for blood. Untreated aortic dissections have a mortality rate of 80% at two weeks from the initial tear and treated aortic dissections have a mortality rate of 40% at five years. One treatment option is Thoracic Endovascular Aortic Repair (TEVAR), which involves placing one or several implants known as stent-grafts or endografts on the inner surface of the aorta. About 38% of TEVAR procedures come with post-procedural complications and approximately 19% to 24% require secondary re-interventions. Computational fluid dynamics (CFD) simulations can be used as a tool to predict post-procedural complications from a fluid mechanical perspective. In this study, the comparison of two post-surgical lumen scenarios is reported by conducting blood simulations using OpenFOAM, an open-source CFD tool. A study is also done on the non-Newtonian nature of blood and results are reported on the influence of using a non-Newtonian viscosity model as opposed to a Newtonian (constant viscosity) model. Validation of the computational grid and the viscosity model is done against experimental results retrieved from another study that used porcine blood.