Ascending aortic aneurysms are a result of microstructural changes leading to altered biomechanical behaviour. Current risk assessment tools only indirectly relate to the aortic wall weakening and fail to capture a significant portion of dissections. Thus, there is a need for finding alternative patient-specific non-invasive markers that correlate with local variations in ex vivo histopathological and mechanical properties. Aortic tissue samples were obtained from both bicuspid (BAV) and tricuspid aortic valves individuals undergoing elective aortic resection. Samples were subjected to biaxial and uniaxial testing to quantify mechanical properties and histopathological analysis to obtain the microstructural properties. Several biaxial biomechanics properties correlated with the microstructural properties and strength and show promise in their potential to be obtained through medical imaging. To further integrate the role of glycosaminoglycans (GAG) in aortopathy, a comparison between GAG accumulation and overall content and their corresponding effects on the biomechanics and elastin properties was conducted. It was seen that a combination of severe accumulation with decreased overall content was associated with signs of elastin degradation and altered biomechanics. The confounding effects of aging were also explored by comparing the elastin-biaxial biomechanics relationship between BAV patients in their 6th and 7th decades. The relationship between elastin degradation and the biomechanics, was seen to differ based on patient age. These results illustrate the variability within the BAV population as well as the need to further establish the effects of aging. Finally for a section of the BAV population, patients were subjected to pre-operative MRI to identify areas of localised elevated wall shear stress (WSS) based on age-matched healthy atlases. Categorical WSS and region of tissue collected were compared with biaxial mechanical properties. The results show that WSS was a better indicator than region for altered biomechanics in BAV tissue with respect to tissue collection region, reinforcing the potential of WSS as a non-invasive marker of aortopathy. This thesis provided insight into the complexity of ascending aortic aneurysmal disease including confounding effects of aging; it also established a potential future direction for non-invasive markers that could improve risk assessment and surgical planning.