Finite Element Analysis on Mechanical Behavior of Occlusion Devices for Atrial Septal Defects

Abstract

Transcatheter closure via occlusion devices has been widely used for the treatment of atrial septal defect (ASD), which is the third most common congenital heart defect in children. Device embolization is one of the major complications of this method, which may require emergent surgeries. In this study, we constructed a finite element model of the ASD occlusion devices (Figulla® Flex II, FFII and Amplatzer® Septal Occluder, ASO) for the purpose of investigating the mechanical behavior of the devices under tensile tests and furtherly the risk of malposition, followed by experimental tests to evaluate the results. The geometry model of the ASD occlusion device was built by processing the photograph of the device via Photoshop, Illustrator, MATLAB and Abaqus, based on the geometrical characteristics of the device. The material (Nitinol) was assumed to be superelastic, and the material properties were obtained by tensile tests of Nitinol wires. The model was pulled in the finite element analysis using Abaqus/Explicit. Experimental tests were carried out under the same condition, and the load-displacement curves were studied to evaluate the results of the simulation, as well as to compare the risk of embolization of two types of devices.