Modelling the mechanobiology of intracranial aneurysm evolution
Dr. Paul Watton (University of Sheffield)
Thursday 10th March, 2016 14:00-15:00 Maths 203
Intracranial aneurysms (IAs) are a disease of the brain vasculature. They appear as a sac-like out-pouching of a part of the arterial wall, inflated by the pressure of the blood that fills them. They are relatively common and affect up to 5% of the adult population. Most remain asymptomatic; however, there is a small but inherent risk of rupture. If rupture occurs there is a 30% to 50% chance of fatality. Consequently, if an IA is detected, clinical intervention may be deemed appropriate. However, interventional procedures are not without risk to the patient. Given the relatively low risk of rupture it would be desirable to be able to identify those aneurysms most at risk of such an episode. This would assist clinical diagnostic procedures and avoid the potentially undesirable consequences of an unnecessary operation. It is envisaged that computational models of IA evolution may help in achieving this aim.
Watton et al. proposed a Fluid-Solid-Growth framework for modelling IA evolution . This utilises a realistic constitutive model of the arterial wall and the evolving structure and composition of the tissue is explicitly linked to local haemodynamic stimuli. The model has been integrated into physiological vasculature geometries and extended to explicitly link G&R to the local haemodynamic and cyclic deformation stimuli [2,3]. Further sophistications now include: representation of endothelial heterogeneity; integration of a constitutive model for the active response of vascular smooth muscle cells and analysis of their influence on IA evolution; extension to thick-walled model of artery and modelling volumetric growth of constituents , representation of a distribution of collagen fibre attachment stretches and remodelling of the distribution; incorporation of signalling pathways (TGF-b, procollagen zymogen) . In this talk, the computational framework for aneurysm evolution will be presented; model limitations and the direction for future research will be discussed.
 Watton PN et al (2009). Coupling the Haemodynamic Environment to the Evolution of Cerebral Aneurysms: Computational Framework and Numerical Examples, J Biomech Eng, 131:101003.
 Aparicio P, Mandaltsi A, Boamah J, Chen H, Selimovic A, Bratby M, Uberoi R, Ventikos Y, Watton PN (2014) Modelling the Influence of Endothelial Heterogeneity on Progression of Arterial Disease: Application to Abdominal Aortic Aneurysm Evolution, International Journal for Numerical Methods in Biomedical Engineering, 30:563-86
 Selimovic A, Ventikos Y, Watton PN (2014) Modelling the Evolution of Cerebral Aneurysms: Biomechanics, Mechanobiology and Multiscale Modelling, Proceedings of the The 23rd International Congress of Theoretical and Applied Mechanics, 10:396-409.
 Eriksson T, Watton PN, Luo XY, Ventikos Y (2014) Modelling Volumetric Growth in a Thick-walled Fibre Composite, Journal of Mechanics and Physics of Solids, 73:134-150.
 Aparicio P, Thompson M, Watton PN (2016) A novel chemo-mechano-biological model of arterial tissue growth and remodelling, Journal of Biomechanics (accepted)