On the role of tissue mechanics in fluid-structure interaction simulations of patient-specific aortic dissection
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Modeling cardiovascular diseases represents a particular challenge from a numerical perspective, especially when it comes to the interaction between solid (aortic wall) and liquid (blood flow). Despite recent advancements in medicine, the prediction and management of aortic dissection remain challenging. This condition typically presents with one or more tears in the intimal layer of the aorta and a following delamination of the aortic wall. Consequently, blood flows into a separate channel, known as the false lumen, running parallel to the original true lumen. In this context, computational models provide invaluable perspectives. We present a numerical framework based on a semi-implicit fluid-structure interaction scheme that captures, inter alia, the layer-specific anisotropic properties of the aortic wall and the non-Newtonian behavior of blood, and considers medical data to derive a patient-specific geometry and flow conditions. We compare hemodynamic indicators and stress measurements in simulations with increasingly complex material models for the vessel tissue ranging from rigid walls to anisotropic hyperelastic materials. Our findings suggest that rigid wall simulations often produce different results than fluid-structure interaction simulations in the given scenario. Considering anisotropic fiber contributions in the tissue model, stress measurements in the aortic wall differ, but shear stress-based biomarkers are less affected.
