Numerical simulation comparison between monolayer and Multilayer Flow Modulator in a cerebral saccular aneurysm

The presence of an uncovered stent in correspondence of a cerebral saccular aneurysm deeply affects the hemodynamic features of the system itself [6]. Differently from the more traditional stent graft, uncovered stents ensure the perfusion through the wired mesh, allowing the blood to enter the aneurysm sac, but they also laminate the entering flow, eliminating the risk of rupture of the aneurysm. In this study the effects on the blood flow of a monolayer flow diverter and of a Cardiatis Multilayer Flow Modulator were compared, in order to determine how the different geometric features of the two products modify the basic characteristics of the flow (velocity, direction, etc.). A standard aneurysm model was also created to serve as a case for this study. Numerical simulations were performed under different setup (steady, unsteady) for three basic configurations (no stent, monolayer diverter, Cardiatis MFM®). The simulation results show how even if both devices laminate the flow entering the aneurysm sac (eliminating the vortex typical of the configuration with no device), Cardiatis grants a more impactful reduction of the blood flow in the aneurysm sac ensuring, at the same time, increased velocity in correspondence of the centerline of the blood vessel.