Large deformations of elastic vessels under atherosclerotic conditions

Cardiovascular diseases remain the major cause of mortality worldwide. Pathologies of the vasculature such as atherosclerosis are often related to biochemical and genetic factors, as well as mechanical effects that strongly change the function and shape of arteries. The present work is part of a general research project that aims to understand better the mechanical mechanisms responsible for atherosclerotic plaque formation and rupture. The chosen approach is to use numerical fluid structure interaction (FSI) methods to study the relative influence of the hemodynamical stresses and the structural stresses generated on plaques, in combination with an experimental approach to validate the results. To meet this aim, a numerical study of a simplified straight vessel exposed to lumen pressure was investigated under quiescent, steady and oscillating flow conditions. As the internal pressure or the velocity increases, the vessel buckles, leading to a nonlinear large deformation behaviour. The results have been validated using theoretical predictions for the buckling thresholds and experiments using ex vivo vessels. Further studies on idealised cardiovascular conditions such as stenosis (i.e., lumen constriction) or aneurysm-like (i.e., arterial wall expansion) formation have also been performed as well as calculations on a aortic arch artery whose geometry has been obtained from mice by Synchrotron imaging techniques.