A three-dimensional, time-dependent analysis of flow through a bileaflet mechanical heart valve: Comparison of experimental and numerical results

King, M.J.; Corden, James Matthew; David, Tim; Fisher, John

doi:10.1016/0021-9290(95)00107-7

Cited by 64 publications

(28 citation statements)

References 11 publications

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“…Use of body-fitted meshes may be able to adequately resolve the leakage flow by use of highly stretched meshes. 3,13,16,22,23,27,32,33,35,36,38,51,52,60,65 However, use of moving meshes presents additional complications of re-meshing, in particular the rather complex task of mesh generation to accommodate changes in geometry to prevent mesh skewness, entanglement, extreme disparity in cell sizes and aspect ratios and so on. All these factors impact negatively on the accuracy and robustness of body-fitted mesh schemes.…”

Section: Introductionmentioning

confidence: 98%

Two-Dimensional Dynamic Simulation of Platelet Activation During Mechanical Heart Valve Closure

et al. 2006

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A major drawback in the operation of mechanical heart valve prostheses is thrombus formation in the near valve region. Detailed flow analysis in this region during the valve closure phase is of interest in understanding the relationship between shear stress and platelet activation. A fixed-grid Cartesian mesh flow solver is used to simulate the blood flow through a bi-leaflet mechanical valve employing a two-dimensional geometry of the leaflet with a pivot point representing the hinge region. A local mesh refinement algorithm allows efficient and fast flow computations with mesh adaptation based on the gradients of the flow field in the leaflet-housing gap at the instant of valve closure. Leaflet motion is calculated dynamically based on the fluid forces acting on it employing a fluid-structure interaction algorithm. Platelets are modeled and tracked as point particles by a Lagrangian particle tracking method which incorporates the hemodynamic forces on the particles. A platelet activation model is included to predict regions which are prone to platelet activation. Closure time of the leaflet is validated against experimental studies. Results show that the orientation of the jet flow through the gap between the housing and the leaflet causes the boundary layer from the valve housing to be drawn in by the shear layer separating from the leaflet. The interaction between the separating shear layers is seen to cause a region of intensely rotating flow with high shear stress and high residence time of particles leading to high likelihood of platelet activation in that region.

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Section: Introductionmentioning

confidence: 98%

Two-Dimensional Dynamic Simulation of Platelet Activation During Mechanical Heart Valve Closure

et al. 2006

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“…19,40 Because of the non-physiologic flow across a MHV, many researchers focused on studying the flow fields. 4,5,10,13,22,24,30,32,42,45,47 They tried to find the cause of thrombosis and hemolysis according to the threshold shear stresses mentioned above by measuring the flow fields in vitro or applying CFD to calculate shear stresses. The results showed that damage to RBCs and platelets were due to Reynolds shear stress in turbulence.…”

Section: Introductionmentioning

confidence: 99%

Estimation of Viscous Dissipative Stresses Induced by a Mechanical Heart Valve Using PIV Data

2009

Ann Biomed Eng

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Among the clinical complications of mechanical heart valves (MHVs), hemolysis was previously thought to result from Reynolds stresses in turbulent flows. A more recent hypothesis suggests viscous dissipative stresses at spatial scales similar in size to red blood cells may be related to hemolysis in MHVs, but the resolution of current instrumentation is insufficient to measure the smallest eddy sizes. We studied the St. Jude Medical (SJM) 27 mm valve in the aortic position of a pulsatile circulatory mock loop under physiologic conditions with particle image velocimetry (PIV). Assuming a dynamic equilibrium assumption between the resolved and sub-grid-scale (SGS) energy flux, the SGS energy flux was calculated from the strain rate tensor computed from the resolved velocity fields and the SGS stress was determined by the Smagorinsky model, from which the turbulence dissipation rate and then the viscous dissipative stresses were estimated. Our results showed Reynolds stresses up to 80 N/m2 throughout the cardiac cycle, and viscous dissipative stresses below 12 N/m2. The viscous dissipative stresses remain far below the threshold of red blood cell hemolysis, but could potentially damage platelets, implying the need for further study in the phenomenon of MHV hemolytic complications.

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“…The graphs showed reasonable agreement with simulation results investigated earlier using FIDAP. 13 The study showed that the central jet was slightly higher than the lateral jet with the rest of features matched. However, the achieved velocity distribution along X-axis in our study had a triple jet structure with central jet having roughly equal magnitude with the lateral jet.…”

mentioning

confidence: 99%

“…Such vortex formation pattern agreed with the numerical simulation and experiment performed by Dasi et al association of wall shear stress with platelet activation, hemolysis and thrombus initiation on top of material properties and contact activation. 4,13 As the valve leaflets open, the blood is being forced through the valve leaflets, resulting in high velocity jets. These velocity jets will in turn cause high velocity gradients and induce high shear stress.…”

mentioning

confidence: 99%

Experimentally Validated Hemodynamics Simulations of Mechanical Heart Valves in Three Dimensions

Nguyen

Kuan

Chen

et al. 2011

Cardiovasc Eng Tech

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Abstract-Mechanical heart valves (MHV) have been widely deployed as a routine surgical treatment option for patients with heart valve diseases due to its durability and performance. Understanding hemodynamics of MHV plays a key role in performance assessment as well as design. In this work, we propose a numerical method for simulations of full three dimensional MHV with moving valve leaflets in a typical human cardiac cycle. A cell-centered finite volume method is employed to model incompressible flows in MHV. As the flow experiences from laminar to turbulence over every cardiac cycle, the unsteady Reynolds average Navier-Stokes (URANS) equations is solved with kÀ and Spalart-Allmaras turbulence models to resolve large scaled turbulent eddies in high Reynolds number flow regimes. URANS approach chosen for the balance of turbulence resolution and computational cost shows good agreement with more detailed turbulence models as well as experimental data. For capturing the large amplitude movement of the valves, we develop an optimization-based moving mesh technique with objective functions operating on different mesh quality metrics. The method is capable of extensively providing an effective way to maintain and improve the mesh quality due to large movement of domain boundaries. The numerical results for laminar and turbulent flows are validated against experimental data using Particle Image Velocimetry technique. The simulation is able to capture essential features of flows in MHV. The triple jet structure is observed in the simulations together with a switching of central orifice jet flow from horizontal axis to vertical axis downstream of the leaflets and the results are well compared with the experimental data. The moving mesh technique has enabled us to simulate a whole cardiac cycle with pulsatile physiological conditions and prescribed motions of the leaflets. The simulations can essentially reproduce the varying pressure profiles at the left ventricle and aorta. The wall shear stress and vorticity can then be deduced from the simulation results to further access the valve performance. This study also constitutes an important step towards understanding hemodynamics in MHV and contributing to the advancement in study of improved MHV.

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A three-dimensional, time-dependent analysis of flow through a bileaflet mechanical heart valve: Comparison of experimental and numerical results

Cited by 64 publications

References 11 publications

Two-Dimensional Dynamic Simulation of Platelet Activation During Mechanical Heart Valve Closure

Two-Dimensional Dynamic Simulation of Platelet Activation During Mechanical Heart Valve Closure

Estimation of Viscous Dissipative Stresses Induced by a Mechanical Heart Valve Using PIV Data

Experimentally Validated Hemodynamics Simulations of Mechanical Heart Valves in Three Dimensions

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