Computational study of aortic hemodynamics for patients with an abnormal aortic valve: the importance of secondary flow at the ascending aorta inlet

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Title: Computational study of aortic hemodynamics for patients with an abnormal aortic valve: the importance of secondary flow at the ascending aorta inlet
Author(s): Xu, XY
Pirola, S
Jarral, O
O'Regan, D
Asimakopoulos, G
Anderson, JR
Pepper, J
Athanasiou, T
Item Type: Journal Article
Abstract: Blood flow in the aorta is helical, but most computational studies ignore the presence of secondary flow components at the ascending aorta (AAo) inlet. The aim of this study is to ascertain the importance of inlet boundary conditions (BCs) in computational analysis of flow patterns in the thoracic aorta based on patient-specific images, with a particular focus on patients with an abnormal aortic valve. Two cases were studied: one presenting a severe aortic valve stenosis and the other with a mechanical valve. For both aorta models, three inlet BCs were compared; these included the flat profile and 1D through-plane velocity and 3D phase-contrast magnetic resonance imaging derived velocity profiles, with the latter being used for benchmarking. Our results showed that peak and mean velocities at the proximal end of the ascending aorta were underestimated by up to 41% when the secondary flow components were neglected. The results for helical flow descriptors highlighted the strong influence of secondary velocities on the helical flow structure in the AAo. Differences in all wall shear stress (WSS)-derived indices were much more pronounced in the AAo and aortic arch (AA) than in the descending aorta (DAo). Overall, this study demonstrates that using 3D velocity profiles as inlet BC is essential for patient-specific analysis of hemodynamics and WSS in the AAo and AA in the presence of an abnormal aortic valve. However, predicted flow in the DAo is less sensitive to the secondary velocities imposed at the inlet; hence, the 1D through-plane profile could be a sufficient inlet BC for studies focusing on distal regions of the thoracic aorta.
Publication Date: 1-Jun-2018
Date of Acceptance: 6-Feb-2018
URI: http://hdl.handle.net/10044/1/57522
DOI: https://dx.doi.org/10.1063/1.5011960
ISSN: 2473-2877
Publisher: AIP Publishing
Start Page: 026101-1
End Page: 026101-14
Journal / Book Title: APL Bioengineering
Volume: 2
Issue: 2
Copyright Statement: © 2018 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)
Sponsor/Funder: Imperial College Healthcare NHS Trust- BRC Funding
Royal Brompton & Harefield NHS Foundation Trust
Imperial College Healthcare NHS Trust- BRC Funding
Commission of the European Communities
Imperial College Healthcare NHS Trust- BRC Funding
Imperial College Healthcare NHS Trust- BRC Funding
Funder's Grant Number: RD410
NIHR RB Cardiovascular BRU
RDB05 79560
642458
RDC04
RDB02
Publication Status: Published
Open Access location: https://aip.scitation.org/doi/10.1063/1.5011960
Online Publication Date: 2018-03-16
Appears in Collections:Faculty of Engineering
Division of Surgery
Clinical Sciences
Imaging Sciences
National Heart and Lung Institute
Chemical Engineering
Faculty of Medicine



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