title: Simulation of arterial dissection by a penetrating external body using cohesive zone modelling.
abstract: In this paper, we study the dissection of arterial layers by means of a stiff, planar, penetrating external body (a 'wedge'), and formulate a novel model of the process using cohesive zone formalism. The work is motivated by a need for better understanding of, and numerical tools for simulating catheter-induced dissection, which is a potentially catastrophic complication whose mechanisms remain little understood. As well as the large deformations and rupture of the tissue, models of such a process must accurately capture the interaction between the tissue and the external body driving the dissection. The latter feature, in particular, distinguishes catheter-induced dissection from, for example, straightforward peeling, which is relatively well-studied. As a step towards such models, we study a scenario involving a geometrically simpler penetrating object (the wedge), which affords more reliable comparison with experimental observations, but which retains the key feature of dissection driven by an external body, as described. Particular emphasis is placed on assessing the reliability of cohesive zone approaches in this context. A series of wedge-driven dissection experiments on porcine aorta were undertaken, from which tissue elastic and fracture parameters were estimated. Finite element models of the experimental configuration, with tissue considered to be a hyperelastic medium, and evolution of tissue rupture modelled with a consistent large-displacement cohesive formulation, were then constructed. Model-predicted and experimentally measured reaction forces on the wedge throughout the dissection process were compared and found to agree well. The performance of the cohesive formulation in modelling externally driven dissection is finally assessed, and the prospects for numerical models of catheter-induced dissection using such approaches is considered.
authors.affiliation: CISTIB, Centre for Computational Imaging and Simulation Technologies in Biomedicine, INSIGNEO Institute for in silico Medicine, Department of Mechanical Engineering, The University of Sheffield, Sheffield, UK. Electronic address: mta08cn@sheffield.ac.uk.
authors.forename: Christopher
authors.initials: C
authors.lastname: Noble
authors.affiliation: Philips Research, Eindhoven, The Netherlands.
authors.forename: Olaf
authors.initials: O
authors.lastname: van der Sluis
authors.affiliation: Philips Research, Eindhoven, The Netherlands.
authors.forename: Ruud M J
authors.initials: RMJ
authors.lastname: Voncken
authors.affiliation: Department of Mechanical Engineering, The University of Sheffield, Sheffield, UK.
authors.forename: Oliver
authors.initials: O
authors.lastname: Burke
authors.affiliation: Philips Research, Eindhoven, The Netherlands.
authors.forename: Steve E
authors.initials: SE
authors.lastname: Franklin
authors.affiliation: Department of Mechanical Engineering, The University of Sheffield, Sheffield, UK.
authors.forename: Roger
authors.initials: R
authors.lastname: Lewis
authors.affiliation: CISTIB, Centre for Computational Imaging and Simulation Technologies in Biomedicine, INSIGNEO Institute for in silico Medicine, Department of Mechanical Engineering, The University of Sheffield, Sheffield, UK.
authors.forename: Zeike A
authors.initials: ZA
authors.lastname: Taylor
mesh_terms: D000784:Aortic Dissection / Q000503:physiopathology*; D000818:Animals; D001011:Aorta / Q000473:pathology*; D001019:Aortic Rupture / Q000503:physiopathology; D020342:Finite Element Analysis; D055595:Mechanical Phenomena; D015203:Reproducibility of Results; D013552:Swine
keywords: Catheter induced dissection; Cohesive zone model; Critical energy release rate; Critical opening displacement; Finite element method; Porcine aorta