Influence of vertebrae and intervertebral disc on stresses in abdominal aortic aneurysms

Computational modelling of stress-strain states in Abdominal Aortic Aneurysms (AAAs) has become an important tool in assessment of their rupture risk in the last decades. As its application potential in clinical practice is increasing with every additional influencing factor considered in the model, many factors have been analysed already. Up-to-date models are based on patient-specific AAA geometry obtained typically from CT-A imaging under a known level of blood pressure. Mean arterial pressure (MAP) is used to create their unloaded geometry [1] which (with other additional features such as residual stresses) may increase the credibility of the results. Material behaviour is also a very important feature to be described correctly. Large deformations of the arterial wall and intraluminal thrombus (ILT) are mostly described using constitutive models based on mean population data gathered from mechanical testing of patient-specific specimens [3]. ILT can be taken into consideration not only for his poroelastic structure reducing the blood pressure on the AAA wall but also for its significant load-bearing contribution. Different mechanical properties across the ILT thickness. Can be considered as a significant feature too. ILT with large thickness also reduces oxygen supply into the AAA wall underneath and consequently changes its mechanical properties (strength)