[Design strategy for balloon-expandable stents made of biodegradable polymers using finite element analysis]

Stents made of biodegradable polymers have first been suggested to treat cardiovascular diseases more than ten years ago. Despite the enormous potential of local drug delivery there is no biodegradable coronary stent available today. Some of the problems concern the insufficient mechanical properties of the stent designs. Therefore a design strategy was developed to improve the mechanical properties of balloon-expandable polymer stents. Starting with compiling the possible geometric strut forms we proceeded to design strut features exhibiting an improved deformation behaviour. The addition of functional structures to improve certain stent characteristics led to stent designs, whose mechanical properties, recoil and collaps behaviour, were determined by 3D Finite Element Analysis. Finally, a mechanical in vitro testing of these stent prototypes was conducted.