Numerical model of aneurysm formation in vascular grafts

Abstract

Background. Using numerical modeling to study biomechanics of implantable devices for cardiovascular healthcare can help specialists understand underlying mechanisms of clinical complications caused by these devices.Aim: To describe the results of numerical modeling of aneurysm formation in vascular grafts based on the simulation of degradation of their mechanical properties.Material and Methods. The simulation was carried out using a three-dimensional computer model obtained by high-resolution computed tomography of the vascular graft “KemAngioProtez” (CJSC “NeoKor”, Russia). Using the 3D model obtained with a specialized script in the Abaqus/CAE environment (Dassault systems, USA), we have simulated the decrease in the elastic modulus (from 100 to 10%) with post-threshold stresses in the material and the accumulation of plastic strain.Results. Undergoing 150 loading cycles, the vascular wall in the model swelled up to 0.7 mm in the radial direction, and its mechanical properties degraded significantly (by 90% compared to baseline) due to prolonged pressure exposure. The value of maximum plastic deformation was 0.55%.Conclusion. Numerical modeling of graft mechanical properties degradation can assist in qualitative and quantitative assessment of the areas of aneurysm formation. The method makes it possible to visualize the swelling areas and can be used as a valuable tool to complement the existing approaches to studying vascular grafts, and biografts in particular.