Haemodynamic and biomechanical biomarker analysis of carotid fibromuscular dysplasia via fluid-structure interaction.

This study aims to investigate the biomechanical behaviour of the carotid artery in patients with fibromuscular dysplasia (FMD) disease. Carotid FMD is an arterial disease lacking either inflammatory or atherosclerotic pathology, which is characterised by segmental disruptions in arterial wall architecture. It is of considerable interest to examine carotid FMD haemodynamics for the identification of clinically meaningful biomechanical biomarkers. Thus, a two-way coupled three-dimensional (3D) fluid-structure interaction (FSI) model was developed that integrates patient-specific vascular geometries, non-Newtonian turbulent blood flow, an orthotropic hyperelastic representation of the arterial wall, and a Windkessel boundary formulation, with emphasis on characterising haemodynamic biomarkers and biomechanical wall responses. The results showed distinct severity-dependent trends among healthy, focal, non-focal, and severe non-focal carotid geometry types. FMD cases exhibited increased velocities and wall shear stresses, while their pressure gradients at the distal end decreased. Additionally, elevation of OSI (oscillatory shear index) and RRT (relative residence time) values was observed in each FMD model indicating higher levels of flow disruption, oscillatory shear, and localised flow stagnation. Non-focal phenotypes showed the largest radial deformation, whereas the focal configuration displayed the highest von-Mises stresses. These findings indicate that as FMD progresses through increasing complexity in its morphological structure, it will be subjected to increasingly adverse haemodynamics and mechanical forces, which are likely to promote endothelial dysfunction and further progression of the disease.Kindly check and confirm the corresponding author of the article and the first/last name of the authors are correctly identified.All others' names and affiliations have been checked.