Analysis of the passive biomechanical behavior of a sheep-specific aortic artery in pulsatile flow conditions

Abstract

In this work, a novel numerical-experimental procedure is proposed, through the use of the Cardiac Simulation Test (CST), device that allows the exposure of the arterial tissue to in-vitro conditions, mimicking cardiac cycles generated by the heart. The main goal is to describe mechanical response of the arterial wall under physiological conditions, when it is subjected to a variable pressure wave over time, which causes a stress state affecting the biomechanical behavior of the artery wall. In order to get information related to stress and strain states, numerical simulation via finite element method, is performed under a condition of systolic and diastolic pressure. The description of this methodological procedure is performed with a sample corresponding to a sheep aorta without cardiovascular pathologies. There are two major findings: the evaluation of the mechanical properties of the sheep aorta through the above-mentioned tests and, the numerical simulation of the mechanical response under the conditions present in the CST. The results state that differences between numerical and experimental circumferential stretch in diastole and systole to distinct zones studied do not exceed 1%. However, greater discrepancies can be seen in the distensibility and incremental modulus, two main indicators, which are in the order of 30%. In addition, numerical results determine an increase of the principal maximum stress and strain between the case of systolic and diastolic pressure, corresponding to 31.1% and 14.9% for the stress and strain measurement respectively; where maximum values of these variables are located in the zone of the ascending aorta and the aortic arch.

Keywords:

• Arteries
• aorta
• biomechanical model
• pulsatile flow
• cardiac simulation test (CST)
• finite element method (FEM)
• uniaxial tensile test

Acknowledgements

The authors wish to express their appreciation to the FONDECYT Project No.1151119 and 1170608 of the Chilean National Research and Development Agency (ANID). Also the Proyecto Basales, the Technological Research unit of the Universidad de Santiago de Chile and the project DICYT 051916GH-PAP are all gratefully acknowledged. In addition, this work was partly funded by ANID - Millennium Science Initiative Program - NCN17_129. Finally, A.Navarrete thanks the support of ANID PFCHA/DOCTORADO BECAS CHILE/2019 − 21190623.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by Comisión Nacional de Investigación Científica y Tecnológica;Departamento de Investigaciones Científicas y Tecnológicas, Universidad de Santiago de Chile;Fondo Nacional de Desarrollo Científico y Tecnológico; Millennium Science Initiative of the Ministry of Economy.