Finite element modeling of cerebral angioplasty using a structural multi-mechanism anisotropic damage model

Arterial progressive damage, softening and non-recoverable deformation are typical effects of percutaneous transluminal angioplasty (PTA), induced mechanically by the overstretching and widening of arterial walls during balloon dilatation. In this paper, we model this controlled vessel injury in cerebral balloon angioplasty by extending a recently developed structural multi-mechanism damage model for cerebral arterial tissue in early stage aneurysms. The current constitutive model focuses on arterial mechanical damage and can characterize the wall anisotropy and subfailure damage of the elastin, ground matrix and collagen, represented by the recruitment of collagen fibers, gradual degeneration, failure of arterial components and changes in the tissue mechanical properties. Cyclic uniaxial response of homogeneous artery models is used to validate the numerical implementation of the constitutive model. Cerebral arteries are modeled as a multi-layer heterogeneous wall model composed of the internal elastic lamina, media and adventitia. Cerebral angioplasty is simulated by contact between the heterogeneous artery model and a simplified balloon model. The states of arterial deformation, tissue damage and wall stress during angioplasty are analyzed, which reproduces the qualitative features of cerebral PTA observed experimentally. The constitutive model and computational methods are demonstrated to be robust in simulating complex tissue response caused by the mechanical intervention of angioplasty, and are applied in more realistic artery-plaque-balloon-stent models. Copyright (c) 2012 John Wiley & Sons, Ltd.