0
TECHNICAL PAPERS: Fluids/Heat/Transport

Comparison of the Hemodynamic and Thrombogenic Performance of Two Bileaflet Mechanical Heart Valves Using a CFD/FSI Model

[+] Author and Article Information
Kris Dumont

Cardiovascular Mechanics and Biofluid Dynamics Research Unit, IBiTech,  Ghent University, Belgium; Department of Biomedical Engineering,  Stony Brook University, Stony Brook, NY 11794-8181

Jan Vierendeels

Department of Flow, Heat, and Combustion Mechanics,  Ghent University, Belgium

Rado Kaminsky, Pascal Verdonck

Cardiovascular Mechanics and Biofluid Dynamics Research Unit, IBiTech,  Ghent University, Belgium

Guido van Nooten

Department of Surgery,  University Hospital Ghent, Belgium

Danny Bluestein1

Department of Biomedical Engineering,  Stony Brook University, Stony Brook, NY 11794-8181danny.bluestein@sunysb.edu

1

Corresponding author.

J Biomech Eng 129(4), 558-565 (Jan 22, 2007) (8 pages) doi:10.1115/1.2746378 History: Received September 06, 2006; Revised January 22, 2007

The hemodynamic and the thrombogenic performance of two commercially available bileaflet mechanical heart valves (MHVs)—the ATS Open Pivot Valve (ATS) and the St. Jude Regent Valve (SJM), was compared using a state of the art computational fluid dynamics-fluid structure interaction (CFD-FSI) methodology. A transient simulation of the ATS and SJM valves was conducted in a three-dimensional model geometry of a straight conduit with sudden expansion distal the valves, including the valve housing and detailed hinge geometry. An aortic flow waveform (60 beats/min, cardiac output 4 l∕min) was applied at the inlet. The FSI formulation utilized a fully implicit coupling procedure using a separate solver for the fluid problem (FLUENT ) and for the structural problem. Valve leaflet excursion and pressure differences were calculated, as well as shear stress on the leaflets and accumulated shear stress on particles released during both forward and backward flow phases through the open and closed valve, respectively. In contrast to the SJM, the ATS valve opened to less than maximal opening angle. Nevertheless, maximal and mean pressure gradients and velocity patterns through the valve orifices were comparable. Platelet stress accumulation during forward flow indicated that no platelets experienced a stress accumulation higher than 35 dyne×s/cm2 , the threshold for platelet activation (Hellums criterion). However, during the regurgitation flow phase, 0.81% of the platelets in the SJM valve experienced a stress accumulation higher than 35 dyne×s/cm2 , compared with 0.63% for the ATS valve. The numerical results indicate that the designs of the ATS and SJM valves, which differ mostly in their hinge mechanism, lead to different potential for platelet activation, especially during the regurgitation phase. This numerical methodology can be used to assess the effects of design parameters on the flow induced thrombogenic potential of blood recirculating devices.

FIGURES IN THIS ARTICLE
<>
Copyright © 2007 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Studied geometries, with valve leaflet in open position. (a)22mm AP ATS open pivot valve geometry. (b)21mm SJM Regent valve geometry.

Grahic Jump Location
Figure 2

Valves leaflets in closed position. (a)22mm AP ATS open pivot valve in closed position. (b)21mm SJM Regent valve geometry in closed position. (c) Difference in hinge design of the two bileaflet mechanical heart valves.

Grahic Jump Location
Figure 3

Inlet aortic velocity-time pattern and spatial profile. (a) Inlet aortic velocity-time pattern. (b) Trapezoidal spatial inlet velocity profile.

Grahic Jump Location
Figure 4

Leaflet angle, velocity-time curves, and pressure gradient-time variation. (a) Leaflet angle-time variation. (b) Velocity profiles in side (SO) and center (CO) orifices. (c) Pressure gradient-time variation.

Grahic Jump Location
Figure 5

Flow field and wall shear stress results during opening of the valves (ATS (left panel), SJM (right panel)) at three different timesteps: 0.02s, 0.08s, 0.12s

Grahic Jump Location
Figure 6

Flow field and wall shear stress results during deceleration of the flow and closing of the valves (ATS (left panel), SJM (right panel)) at three different timesteps: 0.30s, 0.35s, 0.40s

Grahic Jump Location
Figure 7

Wall shear stress results in space (top panel) and in time (bottom panel). (a) Max wall shear stress at t=0.14s for central and side orifice (ATS (left panel), SJM (right panel)). (b) Average leaflet shear stress during cardiac cycle.

Grahic Jump Location
Figure 8

Dispersion patterns of platelets used for the stress accumulation computations during forward (top panel) and regurgitant flow (bottom panel). (a) Dispersion patterns of platelets during forward flow. (b) Dispersion patterns of platelets through the closed valve and the hinges during regurgitant flow.

Grahic Jump Location
Figure 9

Bar charts showing the stress accumulation results during forward (top panel) and regurgitant flow (bottom panel). (a) Platelet stress accumulation during forward flow. Black bars → % scale on the left; gray bars → % scale on the right. (b) Platelet stress accumulation during regurgitant flow. Black bars → % scale on the left; gray bars → % scale on the right.

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In