3D Fluid-Structure Interaction simulation of a bileaflet heart valve opening-closing cycle and comparison with experimental flow data

Abstract

A fully automated numerical procedure has been implemented to enable 3D modelling of the physical behaviour of blood flow through an implanted Mechanical Heart Valve (MHV). For this purpose, a specifically developed Valve Cycle Program was coupled with a commercial Computational Fluid Dynamics (CFD) solver to implement a Fluid-Structure Interaction (FSI) model. A complete opening-closing cycle has been simulated by imposing physiological boundary conditions. A parallel laboratory circulatory mock-loop hosting a MHV has been manufactured to carry out experimental Particle Image Velocimetry (PIV) flow measurements. The predicted flow characteristics were found to be in good agreement with experimental observations. Both numerical and experimental results confirmed that flow patterns and associated shear stresses downstream of the valve result in a low thrombosis and haemolysis potential.

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

“…The occurrence of turbulence in the aorta in consequence of BMAV implantation is also connected to the choice of blood rheological model. As reported in Table 1 , a Newtonian behavior has been commonly assumed in FSI studies of BMAVs ( 27 , 28 , 31 , 33 , 35 , 37 , 38 , 42 – 48 , 50 – 62 , 64 – 68 , 71 – 73 , 75 , 78 , 80 – 85 ). This assumption is considered valid for blood when the flow is laminar, shear rates values are high, and the conduit through which the blood flows has a large diameter ( 89 ).…”

“…Concerning the geometrical modelling of the BMAV, in the majority of FSI studies the device’s geometry was reconstructed to replicate commercially available designs, such as the Bicarbon valve (Corcym Srl, Milan, IT) ( 58 , 59 , 67 , 71 ), the ATS Open Pivot valve (Medtronic, Dublin, IR) ( 54 – 56 , 63 , 75 , 79 ), the On-X valve (Artivion, Kennesaw, GA, USA) ( 38 , 45 ) and valves from St. Jude series (Abbott Laboratories, Chicago, IL, USA) ( 27 , 28 , 31 , 33 , 35 , 37 , 49 – 53 , 57 , 60 – 62 , 64 – 66 , 68 – 70 , 72 – 77 , 81 – 85 ). Nevertheless, idealized valve models, which do not refer to specific commercial designs, are sometimes considered ( Figure 2C ) ( 42 ).…”

“…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 ).…”

“…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 ). Patient-specific geometries, usually reconstructed from magnetic resonance ( 34 , 35 , 47 , 49 , 50 , 61 , 62 ) or computed tomography ( 38 , 45 ) images, consider the actual...…”

“…LES is based on directly resolving larger flow scales and modelling the smaller ones ( 77 ) and it has been adopted for simulating BMAVs both in its classical formulation ( 77 ) and with an implicit LES approach ( 48 ). Approaches based upon the RANS, where turbulence models such as κ-ε ( 34 , 38 , 44 , 45 , 52 , 57 , 71 ) or κ-ω models ( 34 , 36 , 51 ) are implemented as problem closure, have been also largely adopted for describing BMAVs fluid dynamics ( Table 1 ) even if with debatable results, because of the inaccuracy of such models to represent low turbulence flows.…”