Hemodynamic-Structural Multi-Fidelity Assessment of Endovascular Flow Diversion Strategies for Cerebral Aneurysm Treatment: An Integrated Computational and Experimental Framework

Abstract

Subarachnoid hemorrhage after cerebral aneurysm rupture has a 50% first-month fatality rate. Endovascular flow diversion is the primary treatment modality. However, no prior study has compared stents, coils, and the Woven Endo-Bridge hemodynamically integrating hemodynamic results with structural device behavior in one framework. An aneurysm model was reconstructed from computed tomography imaging of a patient, and computational fluid dynamics evaluated multiple hemodynamic metrics across three flow-diversion strategies. Finite element analysis assessed stent geometries with 50%, 55%, and 60% porosity in 316L stainless steel, poly-L-lactic acid, and nitinol. Universal testing machine tests validated the models with printed polylactic acid and thermoplastic polyurethane analogues. Dimensional and elastic-tube analyses tested scale equivalence between the FEA and UTM geometries and the rigid-wall CFD assumption. Patient-specific CFD confirmed a high-risk hemodynamic profile. The stent yielded the lowest peak intra-sac velocity, greatest pressure reduction, near-zero wall shear stress, the only reduction in time-averaged wall shear stress, cycle-averaged TAWSS, and the largest peak-systolic reductions in velocity, WSS, and vorticity. OSI and RRT rose for all three treated configurations, consistent with the hemodynamic signature of flow diversion. FEA reproduced the expected stiffness hierarchy (Steel > Nitinol > PLLA), and TPU was the closest surrogate for Nitinol's elastic recovery. Scaled specimens matched native-scale stiffness within 2.3%. Predicted radial distension was orders of magnitude below native wall values, supporting rigid-wall CFD. Stent-assisted diversion demonstrated the most favorable hemodynamic profile. A 50%-porosity Nitinol stent best matched target elastic mechanics, while 316L stainless steel provided the greatest resistance to radial compression.