Computational modelling to evaluate abdominal aortic aneurysm rupture risk: state-of-the-art, pitfalls and scientific impact

Abdominal aortic aneurysms (AAAs) are a potentially lethal health condition mostly encountered in the aging population of the developed world. Currently, management of these lesions is determined based on the maximum diameter criterion and AAAs larger than 55 mm undergo repair, while those <55 mm receive conservative management and regular surveillance to detect enlargement. Nevertheless, the maximum diameter criterion is a general rule of thumb, which often may result in diagnostic inaccuracies, as indicated by the fact that approximately 10% of ruptured cases are below treatment threshold, while almost 80% of unoperated larger lesions never proceed to rupture. Therefore, individualized patient-specific rupture risk estimation would be desirable. Computational modelling can provide further insight into the progression and rupture of AAAs and several biomechanical variables have been shown to identify lesions with a high-risk profile. Moreover, the hemodynamic environment inside the AAA sac may have several implications for the natural history of these lesions mainly through the accumulation of intraluminal thrombus which has been shown to be an important determinant of the rupture risk. The biomechanical and hemodynamic approach to AAAs’ rupture risk estimation is based on sound physical principles and is a promising tool towards an individualized approach for the management of these lesions.