On stress in abdominal aortic aneurysm: Linear versus non‐linear analysis and aneurysm rupture risk

Abstract

We present comprehensive biomechanical analyses of abdominal aortic aneurysms (AAA) for 43 patients. We compare stress magnitudes and stress distributions within arterial walls of abdominal aortic aneurysms (AAA) obtained using two simulation and modelling methods: (a) Fully automated and computationally very efficient linear method embedded in the software platform Biomechanics based Prediction of Aneurysm Rupture Risk (BioPARR), freely available from https://bioparr.mech.uwa.edu.au/; (b) More complex and much more computationally demanding Non-Linear Iterative Stress Analysis (Non-LISA) that uses a non-linear inverse iterative approach and strongly non-linear material model. Both methods predicted localised high stress zones with over 90% of AAA model volume fraction subjected to stress below 20% of the 99th percentile maximum principal stress. However, for the non-linear iterative method, the peak maximum principal stress (and 99th percentile maximum principal stress) was higher and the stress magnitude in the low stress area lower than for the automated linear method embedded in Bio-PARR. Differences between the stress distributions obtained using the two methods tended to be particularly pronounced in the areas where the AAA curvature was large. Performance of the selected characteristic features of the stress fields (we used 99th percentile maximum principal stress) obtained using BioPARR and Non-LISA in distinguishing between the AAAs that would rupture and remain intact was for practical purposes the same for both methods.

Fluid–structure interaction study for biomechanics and risk factors in Stanford type A aortic dissection

“…This measure is commonly regarded as an indicator of effective stress that contributes to failure 92 . Calculation of von‐Mises stress on the wall is important in identifying regions that may be at higher risk of rupture 93 . The distribution of wall stress (von‐Mises) is shown in Figure 8, along with the stress distribution in cross‐sections at different locations along the thoracic aorta.…”

“…92 Calculation of von-Mises stress on the wall is important in identifying regions that may be at higher risk of rupture. 93 The distribution of wall stress (von-Mises) is shown in Figure 8, along with the stress distribution in cross-sections at different locations along the thoracic aorta. The artery stress values are primarily driven by a combination of blood flow dynamics, wall properties and artery tortuosity.…”

Association of local solid mechanical, hemodynamic and morphological characteristics with ruptured intracranial aneurysm

“…Since the eventual rupture is taken as a tissue failure, it is believed that mechanical and hemodynamic analysis are physics‐based ways to evaluate the aneurysm risk. Considerable efforts have been devoted to analyzing mechanical and hemodynamic characteristics of aneurysms, as well as their associations with morphological characteristics 2–4 . However, influence of solid mechanical, hemodynamic, and morphological characteristics on rupture is not conclusive.…”

“…Considerable efforts have been devoted to analyzing mechanical and hemodynamic characteristics of aneurysms, as well as their associations with morphological characteristics. [2][3][4] However, influence of solid mechanical, hemodynamic, and morphological characteristics on rupture is not conclusive. Conflict conclusion could be found in literature, such as both abnormally low and high wall shear stress (WSS) at aneurysm regions are found in IAs.…”