High wall shear stress can predict wall degradation in ascending aortic
aneurysms: an integrated biomechanics study
aneurysms: an integrated biomechanics study
File(s)
Published version
Author(s)
Salmasi, Mohammad Yousuf Bilal
Pirola, Selene
Sasidharan, Sumesh
Fisichella, Serena
Redaelli, Alberto
Type
Journal Article
Abstract
Background: Blood flow patterns can alter material properties of ascending thoracic aortic aneurysms (ATAA) via vascular wall remodeling. This study examines the relationship between wall shear stress (WSS) obtained from image-based computational modelling with tissue-derived mechanical and microstructural properties of the ATAA wall using segmental analysis.
Methods: Ten patients undergoing surgery for ATAA were recruited. Exclusions: bicuspid aortopathy, connective tissue disease. All patients had pre-operative 4-dimensional flow magnetic resonance imaging (4D-MRI), allowing for patient-specific computational fluid dynamics (CFD) analysis and anatomically precise WSS mapping of ATAA regions (6–12 segments per patient). ATAA samples were obtained from surgery and subjected to region-specific tensile and peel testing (matched to WSS segments). Computational pathology was used to characterize elastin/collagen abundance and smooth muscle cell (SMC) count.
Results: Elevated values of WSS were predictive of: reduced wall thickness [coef −0.0489, 95% CI (−0.0905, −0.00727), p = 0.022] and dissection energy function (longitudinal) [−15,0, 95% CI (−33.00, −2.98), p = 0.048]. High WSS values also predicted higher ultimate tensile strength [coef 0.136, 95% CI (0 0.001, 0.270), p = 0.048]. Additionally, elevated WSS also predicted a reduction in elastin levels [coef −0.276, 95% (CI −0.531, −0.020), p = 0.035] and lower SMC count ([oef −6.19, 95% CI (−11.41, −0.98), p = 0.021]. WSS was found to have no effect on collagen abundance or circumferential mechanical properties.
Conclusions: Our study suggests an association between elevated WSS values and aortic wall degradation in ATAA disease. Further studies might help identify threshold values to predict acute aortic events.
Methods: Ten patients undergoing surgery for ATAA were recruited. Exclusions: bicuspid aortopathy, connective tissue disease. All patients had pre-operative 4-dimensional flow magnetic resonance imaging (4D-MRI), allowing for patient-specific computational fluid dynamics (CFD) analysis and anatomically precise WSS mapping of ATAA regions (6–12 segments per patient). ATAA samples were obtained from surgery and subjected to region-specific tensile and peel testing (matched to WSS segments). Computational pathology was used to characterize elastin/collagen abundance and smooth muscle cell (SMC) count.
Results: Elevated values of WSS were predictive of: reduced wall thickness [coef −0.0489, 95% CI (−0.0905, −0.00727), p = 0.022] and dissection energy function (longitudinal) [−15,0, 95% CI (−33.00, −2.98), p = 0.048]. High WSS values also predicted higher ultimate tensile strength [coef 0.136, 95% CI (0 0.001, 0.270), p = 0.048]. Additionally, elevated WSS also predicted a reduction in elastin levels [coef −0.276, 95% (CI −0.531, −0.020), p = 0.035] and lower SMC count ([oef −6.19, 95% CI (−11.41, −0.98), p = 0.021]. WSS was found to have no effect on collagen abundance or circumferential mechanical properties.
Conclusions: Our study suggests an association between elevated WSS values and aortic wall degradation in ATAA disease. Further studies might help identify threshold values to predict acute aortic events.
Date Issued
2021-10-18
Date Acceptance
2021-09-24
Citation
Frontiers in Bioengineering and Biotechnology, 2021, 9, pp.1-13
ISSN
2296-4185
Publisher
Frontiers Media
Start Page
1
End Page
13
Journal / Book Title
Frontiers in Bioengineering and Biotechnology
Volume
9
Copyright Statement
© 2021 Salmasi, Pirola, Sasidharan, Fisichella, Redaelli, Jarral, O’Regan, Oo, Moore, Xu and Athanasiou. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
License URL
Sponsor
Imperial College Healthcare NHS Trust- BRC Funding
British Heart Foundation
British Heart Foundation Centre for Research Excellence
Imperial College Healthcare NHS Trust- BRC Funding
Identifier
https://www.frontiersin.org/articles/10.3389/fbioe.2021.750656/full
Grant Number
RDC04
RE/18/4/34215
RE/18/4/34215
RDB02
Subjects
CFD
aneurysm
aortic surgery
computational fluid dynamics
computational pathology
magnetic resonance imaging
vascular biomechanics
wall shear stress
0699 Other Biological Sciences
0903 Biomedical Engineering
1004 Medical Biotechnology
Publication Status
Published
Article Number
750656
Date Publish Online
2021-10-18