Characterization of Hemodynamic Performance and Degree of Flow Redirection in the Left Ventricle Dependent on the Mitral Mechanical Heart Valve Orientation

Recent groundbreaking work by Kilner et al. [1] demonstrated that a healthy functioning heart redirects the flow through the left ventricle (LV) in an asymmetric manner, which results in an energy conserving mechanism. Heart valve replacement alters the physiological operation of the heart significantly affecting its hemodynamic performance. As a result, orientation and valve design could play a significant role in the energy efficient operation of the heart; therefore, orienting MHVs so that flow disturbances are minimized enhances the hemodynamic performance of the LV.

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Computational Evaluation of the Haemodynamic Performance of a Novel Prosthetic Heart Valve

Volume 3: 19th International Conference on Advanced Vehicle Technologies; 14th International Conference on Design Education; 10th Frontiers in Biomedical Devices ◽

10.1115/detc2017-67773 ◽

2017 ◽

Author(s):

Mrudang Mathur ◽

Ankit Saxena ◽

Rohan Shad ◽

Anwesha Chattoraj

Keyword(s):

Heart Valve ◽

Clinical Performance ◽

Computational Study ◽

Anticoagulation Therapy ◽

Mechanical Heart Valve ◽

Prosthetic Heart Valve ◽

Effective Orifice Area ◽

Computational Evaluation ◽

Flow Through ◽

Hemodynamic Performance

It has become evident through studies both computational and otherwise, that the characteristics of blood flow through a mechanical heart valve is closely tied to its thrombogenic profile and clinical performance. Despite progress in the field, there remains an unmet clinical need for a heart valve that is both durable and free from the need for anticoagulation therapy. We designed a prototype for a novel mechanical heart valve with the aim of improving hemodynamic performance and obviating the need for anticoagulant therapy. In this paper we present the results of a computational study that compared our prototype mechanical heart valve with a popular commercially available valve, the Medtronic ATS valve. Our results show that the unique design features of our prototype leads to a reduction turbulent flow, along with a reduction in velocity jets by up to 28%, pressure gradient across the valve by 36.7%, and increases in the effective orifice area of the valve by 25.7%.

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Flow Patterns Downstream of a Mechanical Heart Valve During Systole

Volume 2: Fora, Parts A and B ◽

10.1115/fedsm2007-37488 ◽

2007 ◽

Author(s):

P. Oshkai ◽

F. Haji-Esmaeili

Keyword(s):

Turbulent Flow ◽

Heart Valve ◽

Large Scale ◽

Cardiac Cycle ◽

Mechanical Heart Valve ◽

Opening Angle ◽

Image Velocimetry ◽

Imaging Approach ◽

Systolic Phase ◽

Flow Through

Digital particle image velocimetry is employed to study turbulent flow through a bileaflet mechanical heart valve during systolic phase of a cardiac cycle. Unsteady vortex shedding from the valve’s leaflets displays distinct characteristic frequencies, depending on the opening angle of each leaflet. Small- and large-scale transverse oscillations of the separated shear layers are studied using global quantitative flow imaging approach. Turbulent flow structures including jet-like regions and shed vortices are characterized in terms of patterns of instantaneous and time-averaged velocity, vorticity, and turbulence statistics.

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Regurgitant Commissure Flow Through a Closed Polymeric Heart Valve

ASME 2010 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2010-19219 ◽

2010 ◽

Author(s):

Scott C. Corbett ◽

Hamid N.-Hashemi ◽

Ahmet U. Coskun

Keyword(s):

Heart Valve ◽

Heart Valves ◽

Structural Changes ◽

Patient Survival ◽

Improve Patient Survival ◽

Flow Disturbances ◽

Limited Life ◽

Flow Through ◽

Valve Prostheses ◽

Improve Patient

While heart valve prostheses have been used successfully since 1960, outcomes are far from ideal. The underlying problem with bioprostheses is a limited life from structural changes such as calcification and leaflet wear, leading to valve failure. The underlying problem with mechanical heart valves is the presence of flow disturbances which necessitate anticoagulation. A polyurethane valve has the potential to improve upon the shortcomings of existing valves and ultimately improve patient survival.

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Flow in a Mechanical Bileaflet Heart Valve at Laminar and Near-Peak Systole Flow Rates: CFD Simulations and Experiments

Journal of Biomechanical Engineering ◽

10.1115/1.1993665 ◽

2005 ◽

Vol 127 (5) ◽

pp. 782-797 ◽

Cited By ~ 72

Author(s):

Liang Ge ◽

Hwa-Liang Leo ◽

Fotis Sotiropoulos ◽

Ajit P. Yoganathan

Keyword(s):

Heart Valve ◽

Turbulence Modeling ◽

Mechanical Heart Valve ◽

Reynolds Numbers ◽

Navier Stokes ◽

Detached Eddy Simulation ◽

Cfd Simulations ◽

Mean Velocity ◽

Eddy Simulation ◽

Flow Through

Time-accurate, fully 3D numerical simulations and particle image velocity laboratory experiments are carried out for flow through a fully open bileaflet mechanical heart valve under steady (nonpulsatile) inflow conditions. Flows at two different Reynolds numbers, one in the laminar regime and the other turbulent (near-peak systole flow rate), are investigated. A direct numerical simulation is carried out for the laminar flow case while the turbulent flow is investigated with two different unsteady statistical turbulence modeling approaches, unsteady Reynolds-averaged Navier-Stokes (URANS) and detached-eddy simulation (DES) approach. For both the laminar and turbulent cases the computed mean velocity profiles are in good overall agreement with the measurements. For the turbulent simulations, however, the comparisons with the measurements demonstrate clearly the superiority of the DES approach and underscore its potential as a powerful modeling tool of cardiovascular flows at physiological conditions. The study reveals numerous previously unknown features of the flow.

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An Initial Parametric Study on Fluid Flow Through Bileaflet Mechanical Heart Valves Using Computational Fluid Dynamics

Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine ◽

10.1243/pime_proc_1994_208_267_02 ◽

1994 ◽

Vol 208 (2) ◽

pp. 63-72 ◽

Cited By ~ 23

Author(s):

M J King ◽

T David ◽

J Fisher

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Heart Valve ◽

Heart Valves ◽

Mechanical Heart Valve ◽

Volumetric Flow Rate ◽

Flow Fields ◽

Opening Angle ◽

Bileaflet Mechanical Heart Valve ◽

Flow Through

The effect of leaflet opening angle on flow through a bileaflet mechanical heart valve has been investigated using computational fluid dynamics (CFD). Steady state, laminar flow for a Newtonian fluid at a Reynolds number of 1500 was used in the two-dimensional model of the valve, ventricle, sinus and aorta. This computational model was verified using one-dimensional laser Doppler velocimetry (LDV). Although marked differences in the flow fields and energy dissipation of the jets downstream of the valve were found between the CFD predictions and the three-dimensional experimental model, both methods showed similar trends in the changes of the flow fields as the leaflet opening angle was altered. As the opening angle increased the area of recirculating fluid downstream of the leaflets, the pressure drop across the valve and the volumetric flow rate through the outer orifice decreased. For opening angles greater than 80° the jet through the outer orifice recombined with the central jet downstream of the leaflet; for an opening angle of 78° the jet through the outer orifice impinged on the aortic wall before recombining with the central jet. This study suggests that the opening angle has a marked effect on the flow downstream of the bileaflet mechanical heart valve and that valves with opening angles greater than 80° are preferable.

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