On the influence of patient-specific material properties in computational simulations: A case study of a large ruptured abdominal aortic aneurysm

• Published in: International journal for numerical methods in biomedical engineering Vol. 29; no. 2; pp. 150 - 164
• Main Authors: Doyle, Barry J., Callanan, Anthony, Grace, Pierce A., Kavanagh, Eamon G.
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.02.2013; Wiley Subscription Services, Inc
• Subjects: abdominal aortic aneurysm; Aged; Aortic Aneurysm, Abdominal - diagnostic imaging; Aortic Aneurysm, Abdominal - pathology; Aortic Aneurysm, Abdominal - surgery; Aortic Rupture - pathology; Computer Simulation; experimental; Finite Element Analysis; Humans; Male; modelling; Models, Cardiovascular; numerical; patient-specific; rupture; Tensile Strength; Thrombosis - diagnostic imaging; Thrombosis - pathology; Tomography, X-Ray Computed
• ISSN: 2040-7939; 2040-7947; 2040-7947
• DOI: 10.1002/cnm.2515

SUMMARY Patient‐specific modelling of abdominal aortic aneurysm has been shown to have clinical potential. This paper examines a large ruptured abdominal aortic aneurysm where the tissue from the diseased wall and the intraluminal thrombus was excised during open surgical repair and experimentally characterised. The mechanical data were used to develop material parameters that were incorporated into finite element models with measured nonuniform wall thickness. Implementation of the material data into the numerical model increased peak wall stress by 67%, wall strain by 320% and displacement by 177%, when compared with simulations based on material properties available in the literature. Distributions of numerical results were similar for both material data. Magnitudes of numerical results can differ significantly when using patient‐specific material properties and therefore, care should be taken when interpreting numerical results derived from population‐based data.Copyright © 2012 John Wiley & Sons, Ltd. Abdominal aortic aneurysm (AAA) wall tissue and intraluminal thrombus (ILT) were harvested during surgery and then mechanically tested. This data was used in a finite element analysis (FEA) patient‐specific model with measured, non‐uniform, wall thickness. Tissue was much weaker than population‐based data and significantly influenced numerical results. Rupture indices depend on the accuracy of the underlying computational simulation. Care should be taken when developing AAA rupture indices as there can be large inter‐patient and intra‐patient variation in tissue behaviour.