VIRTUAL IMPLANTATION OF A PAEDIATRIC BIODEGRADABLE STENT

Aim: Early restoration of normal blood flow in infants suffering from congenital or acquired constrictions in the great arteries is essential for their vascular development. Considering the contra-indications of balloon angioplasty or conventional stenting in such a young population, this study addresses the development of a biodegradable paediatric stent serving as a temporary scaffold without any obstruction for somatic growth or future interventions. Methods: In order to shorten the development cycle and decrease the amount of in-vitro and animal testing of the new transcatheter device, a complete virtual simulation framework is being developed. First, in-vitro degradation studies and mechanical tests were performed on a polymeric bioresorbable braided wire stent. Based on these experiments, a calibrated and validated finite element model (FEM) was set up. The FEM captures the mechanical behaviour of the stent throughout the degradation process. A patient-specific FEM of congenital constricted pulmonary arteries served as a first virtual anatomy to deploy the stent. Results: Both FEMs combined with a virtual stent deployment simulation formed a first preliminary virtual simulation framework of bioresorbable stent implantation in a paediatric setting. The constructed tool allows us to investigate the influence of a specific biodegradable stent design and a patient-specific vessel geometry on successfully opening constricted branches. Conclusions: A first important step to assess the success rate of biodegradable paediatric implants has been taken. The simulation framework will be further elaborated with other stent designs and generic 3D models of both the pulmonary arteries and the aorta. This tool will allow engineers and clinicians to respectively develop and anticipate the ideal biodegradable implant for each patient specifically.