Is decreased tissue elasticity more important than histopathological changes in ruptures of ascending aortic aneurysms?

BACKGROUND

In this study, we aimed to investigate the natural properties of ascending aortic aneurysms and to compare dilated aortic tissues of patients with ascending aortic aneurysms and the non-pathological aortic tissues of cadavers.

METHODS

Between January 2017 and January 2020, a total of 14 patients (12 males, 2 females; mean age: 66.6±8.4 years; range, 54 to 77 years) who underwent elective ascending aortic surgery without genetic disease or family history in the etiology were included in the study. Aortic tissues taken from the patients with ascending aortic aneurysms and cadavers without any aortic pathology were compared histopathologically and biomechanically. An experienced pathologist performed a histological evaluation with appropriate staining and scoring. In the biomechanical examination, stress-strain curves were created with the uniaxial tensile test. The instantaneous elastic modulus was calculated based on the first regions of the curves (Ei) and the slopes of the linear region close to rupturing (Es).

RESULTS

In the pathological examination, there was no statistically significant difference in the parameters of both the patient and control groups (p>0.05). In the biomechanical examination, Ei values were significantly higher in the patients with ascending aortic aneurysms, while Es values were comparable between the groups (p=0.028 and p=0.609, respectively).

CONCLUSION

Our study results showed that the tissues of the ascending aortic aneurysm were much more rigid, although no significant histopathological changes were detected. These findings are meaningful in understanding the structure of normal and pathological aortic tissue.