Hemodynamics in coil and shape memory polymer foam-embolized intracranial aneurysms

This study presents a detailed numerical investigation of intracranial aneurysms treated with shape memory polymer (SMP) foam and coil embolization. The embolized regions are modeled as porous media, with permeability and form factor values derived from existing literature for SMP foam and two coil configurations. A validated solver in ANSYS Fluent 18.1, incorporating a non-Newtonian Quemada viscosity model and inlet conditions, is used to capture transient hemodynamics. Grid and time step independence, as well as model validation against published studies, are established in the simulation framework. Velocity fields, vortex structures, wall shear stress (WSS), and relative residence time (RRT) are analyzed to understand the effect of embolization. SMP foam significantly reduces intra-aneurysmal velocity and WSS while enhancing RRT, indicating a higher potential for stable thrombus formation compared to coils. The role of systemic pressure conditions is evaluated through ±10% and ±20% perturbations to the inflow waveform. Hypertension increases intra-aneurysmal flow and WSS, which may compromise treatment success, while hypotension enhances flow stagnation and increases RRT. The results demonstrate that SMP foam embolization offers superior flow disruption and clot-promoting conditions. It is also noted that inducing mild hypotension during or post-treatment may support improved clinical outcomes from a hemodynamics perspective.