Modelling evolution and the evolving mechanical environment of saccular cerebral aneurysms

P. N. Watton, A. Selimovic, N. B. Raberger, P. Huang, G. A. Holzapfel, Y. Ventikos

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A fluid-solid-growth (FSG) model of saccular cerebral aneurysm evolution is developed. It utilises a realistic two-layered structural model of the internal carotid artery and explicitly accounts for the degradation of the elastinous constituents and growth and remodelling (G&R) of the collagen fabric. Aneurysm inception is prescribed: a localised degradation of elastin results in a perturbation in the arterial geometry; the collagen fabric adapts, and the artery achieves a new homeostatic configuration. The perturbation to the geometry creates an altered haemodynamic environment. Subsequent degradation of elastin is explicitly linked to low wall shear stress (WSS) in a confined region of the arterial domain. A sidewall saccular aneurysm develops, the collagen fabric adapts and the aneurysm stabilises in size. A quasi-static analysis is performed to determine the geometry at diastolic pressure. This enables the cyclic stretching of the tissue to be quantified, and we propose a novel index to quantify the degree of biaxial stretching of the tissue. Whilst growth is linked to low WSS from a steady (systolic) flow analysis, a pulsatile flow analysis is performed to compare steady and pulsatile flow parameters during evolution. This model illustrates the evolving mechanical environment for an idealised saccular cerebral aneurysm developing on a cylindrical parent artery and provides the guidance to more sophisticated FSG models of aneurysm evolution which link G&R to the local mechanical stimuli of vascular cells.

Original languageEnglish
Pages (from-to)109-132
Number of pages24
JournalBiomechanics and Modeling in Mechanobiology
Issue number1
Publication statusPublished - Feb 2011
Externally publishedYes


  • Aneurysm
  • Cerebral
  • Cyclic stretch
  • Finite elasticity
  • Growth
  • Haemodynamics
  • OSI
  • Remodelling
  • RRT
  • WSS
  • WSSG

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