Biomechanics of abdominal aortic aneurysm

Abstract

Abdominal aortic aneurysm (AAA) is a condition whereby the terminal aorta permanently dilates to dangerous proportions, risking rupture. The biomechanics of AAA has been studied with great interest since aneurysm rupture is a mechanical failure of the degenerated aortic wall and is a significant cause of death in developed countries. In this review article, the importance of considering the biomechanics of AAA is discussed, and then the history and the state-of-the-art of this field is reviewed--including investigations into the biomechanical behavior of AAA tissues, modeling AAA wall stress and factors which influence it, and the potential clinical utility of these estimates in predicting AAA rupture.

Dynamics of pulsatile flow through model abdominal aortic aneurysms

“…Presently, clinical intervention is recommended if the maximum diameter reaches 5.0 cm in women and 5.5 cm in men or if the maximal diameter increases by more than 0.5-1 cm in one year (Grootenboer et al 2009). Yet, as observed by Vorp (2007), many smaller lesions rupture (13 % of those of less than 5 cm), while larger lesions may not rupture over long periods (54 % of those of over 7 cm). This leaves physicians to face the dilemma of either subjecting patients to a complex surgery with high morbidity and complications or to an unknown risk of rupture, to paraphrase Lasheras (2007).…”

Initiation of aneurysms as a mechanical bifurcation phenomenon

“…However, how such factors manifest themselves in changing the mechanical behaviour of arteries before aneurysm formation is still not fully understood. Existing studies in the bio-mechanical community have largely focussed on modeling the material properties of mature aneurysm tissues and the growth of aneurysms when they have already formed; see, e.g., Humphrey and Rajagopal [1], Venkatasubramaniam et al [2], Watton et al [3], Baek et al [4,5], Vande Geest et al [6], Vorp [7], Watton and Hill [8], and the references therein. Such studies are obviously important in guiding a clinician when to intervene when an aneurysm has been diagnosed.…”

Finite Element Implementation of a Structurally-Motivated Constitutive Relation for the Human Abdominal Aortic Wall with and without Aneurysms

“…The latter application was used successfully in this paper to benchmark an implementation of the four fiber model in the finite element program COMSOL Multiphysics. The use of mean values of the material parameters in finite element models is common [10]. But here the mean values indicate that there is not a significant difference between the groups of 31-60 years and 61-79 years in the biomechanical properties.…”