Development and Finite Element Implementation of a Nearly Incompressible Structural Constitutive Model for Artery Substitute Design

Compliance mismatch between a host artery and a vascular graft causes hemodynamic disturbance and stress concentration, which may lead to thrombus formation at an early stage and to neointimal hyperplasisa near the anastomosis at a later stage [1]. To optimal design artery substitutes, the requirements of geometric and compliance matching at mean blood pressure must be determined and used to guide the fabrication of the unloaded conduit with proper diameter and wall thickness. Given the range and complexity of structural behaviors that can be produced by independently varying structural properties of individual layers (fiber type, density, orientation and layer thickness), a sophisticated computational model is required to determine these conduit design parameters. In this paper, a novel nearly incompressible structural model was formulated and implemented into the commercial finite element code ABAQUS (Pawtucket, RI) for finite element artery inflation simulations. The profound artery compliance changes due to variations of fiber properties, the nearly incompressibility control parameter D, and different properties of intima-media and adventitia were investigated.