Distensibility of Deformable Aortic Replicas Assessed by an Integrated In-Vitro and In-Silico Approach

• Published in: Bioengineering (Basel) Vol. 9; no. 3; p. 94
• Main Authors: Di Micco, Luigi, Comunale, Giulia, Bonvini, Stefano, Peruzzo, Paolo, Susin, Francesca Maria
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 26-02-2022; MDPI
• Subjects: Aorta; Aortic arch; aortic compliance; aortic distensibility; aortic phantom; Bioengineering; Compliance; Coronary vessels; Deformation; Diameters; Experiments; Flow velocity; Fluid dynamics; Fluid-structure interaction; Formability; FSI simulation; Hemodynamics; in-vitro experiments; Medical equipment; Physiology; pulse-duplicator; Silicones; aortic phantom; pulse-duplicator; aortic distensibility; FSI simulation; aortic compliance; in-vitro experiments
• DOI: 10.3390/bioengineering9030094
• EISSN: 2306-5354

The correct estimation of the distensibility of deformable aorta replicas is a challenging issue, in particular when its local characterization is necessary. We propose a combined in-vitro and in-silico approach to face this problem. First, we tested an aortic silicone arch in a pulse-duplicator analyzing its dynamics under physiological working conditions. The aortic flow rate and pressure were measured by a flow meter at the inlet and two probes placed along the arch, respectively. Video imaging analysis allowed us to estimate the outer diameter of the aorta in some sections in time. Second, we replicated the in-vitro experiment through a Fluid-Structure Interaction simulation. Observed and computed values of pressures and variations in aorta diameters, during the cardiac cycle, were compared. Results were considered satisfactory enough to suggest that the estimation of local distensibility from in-silico tests is reliable, thus overcoming intrinsic experimental limitations. The aortic distensibility (
) is found to vary significantly along the phantom by ranging from 3.0 × 10
mmHg
in the ascending and descending tracts to 4.2 × 10
mmHg
in the middle of the aortic arch. Interestingly, the above values underestimate the
obtained in preliminary tests carried out on straight cylindrical samples made with the same material of the present phantom. Hence, the current results suggest that
should be directly evaluated on the replica rather than on the samples of the adopted material. Moreover, tests should be suitably designed to estimate the local rather than only the global distensibility.