Computational Modeling for Fluid–Structure Interaction of Bioprosthetic Heart Valve with Different Suture Density: Comparison with Dynamic Structure Simulation

In this paper, a parametric geometry model based on elliptic and conic surfaces was developed for bioprosthetic heart valve (BHV) simulation. The valve material was modeled by a hyperelastic nonlinear anisotropic solid model. Different suture densities could be substituted by various bonded points between artery vessel and the leaflets as boundary conditions in the computational modeling. Besides these two assumptions that dynamic structure (DS) and fluid–structure interaction (FSI) both shared, the latter need incompressible viscous Newton fluid model to depict bloodstream passing through the BHV. Immersed boundary (IB) method was introduced to solve the FSI simulation. In addition, the DS analysis applied transvalvular pressure on the valve while FSI had left ventricular pressure on fluid inlet as initials. There was inconsistency between the moments of the maximum deformation and the maximum loading in both simulations. Although a similar trend of deformation lagging the load was viewed, the extent of delay in FSI was much smaller compared with that in DS simulation. The deformed profiles in cross-sectional views were shown in one picture to illustrate different dynamic responses caused by distinct assumptions. Percent of open area at the moments when the maximum deformation occurred was defined to show which calculation achieved better approximation for precise hemodynamics. Fixed point was given as boundaries between BHV and artery in the modeling part. Calculations showed that the more the fixed points in this bonded contact, the lower the principal stress was. The maximum shear stress showed a different trend. It had a different trend. Stress concentration in the conjunction area made it high-risk to be teared. Different suture densities had significant impaction in FSI simulations. With that analysis our work achieved a more comprehensive simulation to describe true hemodynamics of a BHV implanted in artery. The artery vessel had particular dynamic response under such assumptions, gradient existed in the maximum principal stress distribution diagram, from inner wall through which blood passing to the outer wall. Results showed a large suture density was suggested in BHV implantation.