Application of a strong FSI coupling scheme for the numerical simulation of bileaflet mechanical heart valve dynamics: study of wall shear stress on the valve leaflets

Abstract

Abstract:One of the major challenges in the design of bileaflet mechanical heart valves (BMHVs) is reduction of the blood damage generated by non-physiological blood flow. Numerical simulations provide relevant insights into the (fluid) dynamics of the BMHV and are used for design optimization. In this paper, a strong coupling algorithm for the partitioned fluid-structure interaction (FSI) simulation of a BMHV is presented. The convergence of the coupling iterations between the flow solver and the leaflet motion solver is accelerated by using a numerically calculated Jacobian with the derivatives of the pressure and viscous moments acting on the leaflets with respect to the leaflet accelerations. The developed algorithm is used to simulate the dynamics of a 3D BMHV in three different geometries, allowing an analysis of the solution process. Moreover, the leaflet kinematics and the general flow field are discussed, with special focus on the shear stresses on the valve leaflets.

Fluid-structure interaction simulation of mechanical aortic valves: a narrative review exploring its role in total product life cycle

“…Simplified hinge geometry typically results in leaflet rotation being limited by angular constraints rather than by the blocking mechanism of the hinge. Additionally, the friction in the hinge is usually neglected ( 33 , 35 , 38 , 41 , 49 , 55 , 56 , 58 , 61 – 63 , 67 , 69 ), since it is much smaller than fluid forces and reliable coefficients are difficult to retrieve ( 49 , 67 ).…”

“…Idealized geometries usually neglect the curvature of the ascending aorta, representing the region of interest as a straight tube. Straight tube geometries may include idealized sinuses ( 27 , 28 , 31 , 33 , 36 , 37 , 39 – 41 , 46 , 48 , 52 , 55 – 58 , 63 , 65 , 67 , 68 , 71 , 73 , 74 , 78 , 80 , 83 – 85 ) or surfaces of revolution ( 44 , 51 , 53 , 58 – 60 , 66 , 69 , 72 , 76 , 77 , 81 ) in their proximal part to account for the presence of the sinuses of Valsalva ( Figure 2E , Table 1 ), as done for in vitro set-ups ( 87 , 88 ). Straight geometries with or without aortic sinuses may also be designed to replicate experimental set-ups ( 28 , 33 , 37 , 41 , 48 , 66 , 67 , 71 , 72 , 76 , 81 ) or aortic prostheses designs ( 53 , 58 , 59 ) ( Table 1 ).…”

“…Calculation verification activities were conducted by analyzing result sensitivity to discretization grid ( 31 , 34 , 36 , 38 – 41 , 43 , 45 , 52 , 54 , 56 , 67 – 70 , 73 , 78 , 80 , 85 ), to time step ( 34 , 36 , 40 , 54 , 56 , 73 , 78 , 80 ) and specific parameters of the FSI algorithm ( 55 , 56 ), as reported in Table 4 .…”

“…Prospectively planned validation is feasible solely when in-house experimental tests can be conducted. Therefore, validation was often conducted against retrospective data either by qualitatively highlighting similarities in results ( 34 , 44 , 47 , 49 , 50 , 55 , 56 , 58 – 62 , 64 , 73 , 75 , 78 – 80 , 82 , 83 ) or, more rigorously ( Table 4 ), through a quantitative comparison of simulations and experimental results ( 31 , 36 , 38 – 40 , 45 , 51 , 52 , 57 , 65 , 67 – 69 , 85 ).…”

State-of-the-art numerical fluid–structure interaction methods for aortic and mitral heart valves simulations: A review

“…The calculation step for the Jacobian was made more efficient in another study by Annerel et al 187 For the method discussed previously, three consecutive iterations are needed in which the perturbation vectors are perpendicular to each other. For a good estimation of the Jacobian, they mentioned that these vectors need not to be perpendicular but only significantly large in magnitude.…”