Artery Research

Volume 26, Issue Supplement 1, December 2020, Pages S28 - S29

P.08 Biomechanical Characterization of Ascending Thoracic Aortic Aneurysms in Humans: A Continuum Approach to in vivo Deformations

Authors
Shaiv Parikh1, 2, *, Bart Spronck1, 2, 3, Gijs Debeij1, 4, Berta Ganizada1, 4, Mitch Ramaekers1, 5, 6, Simon Schalla1, 5, 6, Ehsan Natour1, 4, Jos Maessen1, 4, Tammo Delhaas1, 2, Wouter Huberts1, 2, Elham Bidar1, 4, Koen Reesink1, 2
1CARIM School for Cardiovascular Diseases, Maastricht University
2Department of Biomedical Engineering, Heart and Vascular Centre, Maastricht University
3Department of Biomedical Engineering, School of Engineering & Applied Science, Yale University
4Department of Cardiothoracic Surgery, Heart and Vascular Centre, Maastricht University Medical Centre
5Department of Radiology and Nuclear Medicine, Maastricht University Medical Centre
6Department of Cardiology, Heart and Vascular Centre, Maastricht University Medical Centre, Maastricht
*Corresponding author. Email: s.parikh@maastrichtuniversity.nl
Corresponding Author
Shaiv Parikh
Available Online 31 December 2020.
DOI
10.2991/artres.k.201209.022How to use a DOI?
Keywords
Aneurysm; in vivo; characterisation
Abstract

Background: Dysfunctional cellular mechanosensing appears central to aneurysm formation [1]. We aimed to derive material parameters of aneurysm tissue from in vivo deformations, which may increase insight into the underlying structural integrity of the pathological tissue.

Methods: Videos of tracking markers (example Video in supplement, screenshot in Figure) placed on ascending aortic segments were captured alongside radial arterial blood pressure in patients undergoing open-thorax ascending thoracic aorta aneurysm (ATAA) repair (n = 5) and coronary bypass (controls; n = 2). Normalised cross-correlation was used to determine marker displacements, resulting in estimates of systolic/diastolic diameters, distensibility, and cyclic axial engineering strain. A thin-walled, cylindrical geometry was assumed, with amorphous (Neo-Hookean) and fibrous (two-family) constitutive contributions [2]. This framework was fitted to individual patient measurements, by varying parameters c (amorphous material constant), k1 and k2 (fiber stiffness and strain stiffening parameter), β (fiber angle w.r.t. circumferential direction), unloaded intact length (L), and internal radius (Ri).

Figure

Left: Example of ascending aortic region of interest with tracking markers. Right: Data presented as mean ± standard deviation. SBP/DBP, systolic/diastolic blood pressure. Estimated properties are defined in the text.

Results: Axial strain tended to be lower (expected) and distensibility larger (unexpected) in aneurysm than controls (Figure). However, the intrinsic pressure-dependence of distensibility must be considered when drawing conclusions related to differences in structural stiffness between both groups [3]. Material stiffness parameters (c and k1) appeared higher in aneurysm patients than in controls which is in line with previous studies in mice [4].

Conclusion: We are developing a method to determine ATAA material properties from in vivo deformations and observed increased material stiffness in ATAA.

Copyright
© 2020 Association for Research into Arterial Structure and Physiology. Publishing services by Atlantis Press International B.V.
Open Access
This is an open access article distributed under the CC BY-NC 4.0 license (http://creativecommons.org/licenses/by-nc/4.0/).

Journal
Artery Research
Volume-Issue
26 - Supplement 1
Pages
S28 - S29
Publication Date
2020/12/31
ISSN (Online)
1876-4401
ISSN (Print)
1872-9312
DOI
10.2991/artres.k.201209.022How to use a DOI?
Copyright
© 2020 Association for Research into Arterial Structure and Physiology. Publishing services by Atlantis Press International B.V.
Open Access
This is an open access article distributed under the CC BY-NC 4.0 license (http://creativecommons.org/licenses/by-nc/4.0/).

Cite this article

TY  - JOUR
AU  - Shaiv Parikh
AU  - Bart Spronck
AU  - Gijs Debeij
AU  - Berta Ganizada
AU  - Mitch Ramaekers
AU  - Simon Schalla
AU  - Ehsan Natour
AU  - Jos Maessen
AU  - Tammo Delhaas
AU  - Wouter Huberts
AU  - Elham Bidar
AU  - Koen Reesink
PY  - 2020
DA  - 2020/12/31
TI  - P.08 Biomechanical Characterization of Ascending Thoracic Aortic Aneurysms in Humans: A Continuum Approach to in vivo Deformations
JO  - Artery Research
SP  - S28
EP  - S29
VL  - 26
IS  - Supplement 1
SN  - 1876-4401
UR  - https://doi.org/10.2991/artres.k.201209.022
DO  - 10.2991/artres.k.201209.022
ID  - Parikh2020
ER  -