A multi-physics growth model with fluid-structure interactions for blood flow and re-stenosis in rat vein grafts: A growth model for blood flow and re-stenosis in grafts

Vein graft is commonly used to replace malfunctioned arteries. However, intimal hyperplasia (IH) and re-stenosis often occur after surgery leading to serious clinical problems. A multi-physics computational model with tube wall growth and fluid-structure interactions and an iterative mixed method using finite volume, generalized finite difference and finite elements are introduced to simulate focal intimal hyperplasia and blood flow in rat abdominal artery with a vein graft. Physical parameters and physiological geometries from in vivo experimental data are used in model development and verifications. Our results indicate that the mismatches in geometry and mechanical properties between the host artery and the vein graft cause considerable disturbance in flow shear stress, eddy flow, tube wall deformation, and tensile stress/strain distributions. Focal intimal hyperplasia and re-stenosis process are closely related to eddy flow and low and oscillating shear stresses. A constitutive growth function which governs the IH growth is quantified based on experimental data and computational simulations. Further investigation of effects of other factors such as tensile stress and various cell interactions is needed to fully understand IH growth and re-stenosis process.