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

Shaiv Parikh; Bart Spronck; Gijs Debeij; Berta Ganizada; Mitch Ramaekers; Simon Schalla; Ehsan Natour; Jos Maessen; Tammo Delhaas; Wouter Huberts; Elham Bidar; Koen Reesink

doi:10.2991/artres.k.201209.022

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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.201209.022 How 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 (R_i).

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.
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/).

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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.201209.022 How to use a DOI?
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

ris enw bib

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  -

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