Region- and layer-specific mechanical and microstructural properties of human ascending thoracic aortic aneurysms

Abstract

Ascending thoracic aortic aneurysms are pathological enlargements of the vessel at the level of the thoracic ascending aorta. Understanding the biomechanical properties of the aorta may provide complementary information to aneurysm morphology to improve risk of rupture assessment. In this research, layer- and region-specific mechanical and microstructural properties of aneurysmal and healthy tissues were studied using biaxial tensile tests and histology. Aorta consists of four regions including anterior, posterior, large and small curvatures. From each of these regions, two adjacent specimens were harvested. One of them was considered as composite wall, while two layers of intima/media and adventitia were separated for the adjacent specimen and tested individually. Our results showed no significant regional differences in mechanical characterizations and elastin contents of the both healthy and aneurysmal specimens. However, significant differences were found in mechanical and structural properties between media and adventitia layers.