Relationships between geometrical parameters and mechanical properties for a helical braided flow diverter stent.

BACKGROUND: Although flow diversion is a promising procedure for aneurysm treatment, the safety and efficacy of this strategy have not been sufficiently characterized. Both mechanical properties and flow reduction effects are important factors in the design of an optimal stent. OBJECTIVE: We aimed to clarify the contributions of strut size and pitch to the mechanical properties (radial stiffness and longitudinal flexibility) and geometric characteristics (porosity and pore density) related to flow reduction effects. METHODS: Crimping and bending behaviors of the stents were simulated with the finite element method. The relationships between the mechanical properties and geometric characteristics were investigated by changing the strut size and pitch. RESULTS: Within the porosity range of 79-82%, the radial stiffness of the stent was similarly influenced by either the strut size or pitch. However, the longitudinal flexibility tended to be influenced more by strut size than by pitch. CONCLUSIONS: Adjusting the strut size rather than the pitch can change the mechanical properties while minimizing the change in porosity or pore density related to flow reduction effects.