heal.abstract |
This study investigates the mechanical properties of the aneurysmatic ascending aorta through radial tensile
testing, focusing on the behavior of different anatomical regions and layers of the aortic wall. The primary aim is
to examine how rupture propagates between the intima-media and media-adventitia layers, and to assess how
these mechanical properties vary across four anatomical regions (anterior, right lateral, posterior, and left lateral)
of the aorta. Specimens from twelve patients were subjected to direct tension tests, with force-displacement
curves used to analyze key mechanical parameters, including maximum force (Fmax), yield force (Fyield), strain, and
elastic modulus.
The samples were collected from patients at Hygeia Hospital between September 2023 and February 2024. The
experimental procedures were conducted at the Center of Clinical, Experimental Surgery & Translational
Research at the Biomedical Research Foundation of the Academy of Athens (BRFAA). For the mechanical testing,
a fully automated Vitrodyne V1000 Universal tensile testing machine was used, equipped with specially
developed specimen grips to ensure precise and consistent measurements during the direct tension tests.
The results were contextualized within the framework of existing literature on the mechanical behavior of the
aortic wall, particularly in relation to rupture initiation and propagation. The study found that the intima-media
interface exhibits significantly higher mechanical resistance, with greater Fmax and elastic modulus values
compared to the media-adventitia interface, indicating that the inner layers of the aorta are stronger and more
resistant to rupture. In contrast, the outer layers showed greater variability and lower mechanical resistance,
making them more prone to rupture initiation. These findings align with previous studies that have demonstrated
the mechanical vulnerability of the media-adventitia interface in pathological conditions such as aortic
dissections. Furthermore, regional differences were observed, with the posterior and right lateral regions
exhibiting higher mechanical resistance compared to the anterior and left lateral regions, suggesting that the
structural integrity of the aorta varies across different anatomical locations. Patient-specific factors such as age,
gender, and valve morphology also influenced the mechanical behavior of the aortic wall. Younger patients
exhibited higher mechanical strength, while patients with bicuspid aortic valves (BAV) showed lower resistance
to rupture compared to those with tricuspid aortic valves (TAV). These findings emphasize the importance of
considering individual patient characteristics when assessing rupture risk and planning treatment. In conclusion,
this study provides valuable insights into the layer-specific and region-specific mechanical properties of the
aneurysmatic ascending aorta, highlighting the critical role of the intima-media interface in maintaining aortic
integrity. The findings have significant implications for the clinical management of aortic aneurysms and
dissections, particularly in terms of identifying patients at higher risk of rupture and tailoring interventions
accordingly. Future research should focus on integrating mechanical testing with histological analyses to further
explore the structural factors that influence aortic wall failure. |
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