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Current Directions in Biomedical Engineering

Joint Journal of the German Society for Biomedical Engineering in VDE and the Austrian and Swiss Societies for Biomedical Engineering

Editor-in-Chief: Dössel, Olaf

Editorial Board: Augat, Peter / Buzug, Thorsten M. / Haueisen, Jens / Jockenhoevel, Stefan / Knaup-Gregori, Petra / Kraft, Marc / Lenarz, Thomas / Leonhardt, Steffen / Malberg, Hagen / Penzel, Thomas / Plank, Gernot / Radermacher, Klaus M. / Schkommodau, Erik / Stieglitz, Thomas / Urban, Gerald A.


CiteScore 2018: 0.47

Source Normalized Impact per Paper (SNIP) 2018: 0.377

Open Access
Online
ISSN
2364-5504
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Computational flow analysis of the washout of an aortic valve by means of Eulerian transport equation

Michael Stiehm
  • Corresponding author
  • Institute for ImplantTechnology and Biomaterials e.V., Friedrich- Barnewitz-Str. 4, Rostock- Warnemünde, Germany
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  • Other articles by this author:
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/ Finja Borowski / Sebastian Kaule / Robert Ott / Sylvia Pfensig / Stefan Siewert
  • Institute for Implant Technology and Biomaterials e.V., Rostock- Warnemünde, Germany
  • Institute for Biomedical Engineering, Rostock University Medical Center, Rostock- Warnemünde, Germany
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/ Klaus-Peter Schmitz / Alper Ö Öner / Niels Grabow
  • Institute for Biomedical Engineering, Rostock University Medical Center, Rostock- Warnemünde, Germany
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Published Online: 2019-09-18 | DOI: https://doi.org/10.1515/cdbme-2019-0032

Abstract

Although the development of the transcatheter aortic valve (TAV) has saved many lives of inoperable patients and has a very good clinical outcome, concerns about valve thrombosis are increasing. Due to the potential risk of late clinically relevant events, the US Food and Drug Administration (FDA) suggests a careful systematic investigation of thrombosis and reduced leaflet motion related to hemodynamic changes induced by TAV implantation. Furthermore, recently published position papers of the ISO working group address numerical and experimental flow field assessment of TAV. In particular, pathologically high shear rates and a reduced washout of the sinuses may increase the risk of valve thrombosis and should therefore be investigated. By means of fluid-structure interaction (FSI) as a powerful in silico tool, the transient flow field in an aortic valve was analyzed. A linear elastic behavior was assumed for leaflet material properties (Young modulus: 10 MPa, Poisson ratio: 0.46 and leaflet material density: 1000 kg/m3) and blood was specified as a homogeneous, Newtonian and incompressible fluid (fluid density: 1060 kg/m3 and a dynamic viscosity: 0.0035 Pa s). In this numerical study we present a Eulerian approach, which is based on transport equation of the residence time (RT) as a passively transported scalar. It can be clearly seen that the RT is significantly higher in the sinus referred to the main flow. At time step t = 0.25 s, the average residence time in the main flow is RTavg ≈ 0.05 s, whereas RT ≈ 0.25 s in the sinus. In particular, RT is a valuable hemodynamic metric to quantify the washout of the sinus in order to evaluate the thrombogenic potential of TAV devices. Further studies will concentrate on particle image velocimetry measurements for validation purposes. In particular the velocity in the sinus and therefore the washout is one important hemodynamic key feature that has to be improved for future TAV designs.

Keywords: Washout; residence time; scalar transport; aortic valve

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Published Online: 2019-09-18

Published in Print: 2019-09-01


Citation Information: Current Directions in Biomedical Engineering, Volume 5, Issue 1, Pages 123–126, ISSN (Online) 2364-5504, DOI: https://doi.org/10.1515/cdbme-2019-0032.

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© 2019 by Walter de Gruyter Berlin/Boston. This work is licensed under the Creative Commons Attribution 4.0 Public License. BY 4.0

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