Impact of differentiating factors on the hemodynamics of umbrella-shaped and fusiform-shaped inferior vena cava filters: A computational fluid dynamics simulation study

This work applies computational fluid dynamics to carry out a systematic investigation of two representative inferior vena cava filters (IVCFs): the umbrella-shaped Denali and the fusiform-shaped OptEase IVCFs. The study emphasizes how blood rheology, inferior vena cava (IVC) diameter, and flow rate influence the hemodynamic environment surrounding these devices. The simulations indicate that although the Newtonian assumption preserves the global flow pattern, it largely exaggerates the downstream stagnation region (roughly twice that predicted by non-Newtonian models) and reduces the overall velocity magnitude (centerline velocity drops by about 30%). It also weakens the acceleration inside the filter and underestimates both wall shear stress (WSS) and flow resistance. Such discrepancies could mislead clinical evaluation and structural safety assessments. Among the five non-Newtonian rheological models examined, all yield similar flow field distributions, but clear variations appear in WSS and resistance. The simplified cross model predicts the largest values, whereas the Carreau model provides intermediate results, thus offering a more representative choice. A smaller IVC diameter markedly lengthens the post-filter stagnation zone (at 15 mm, nearly twice that at 25 mm) and substantially increases filter-surface WSS, which may enhance thrombus trapping and dissolution yet simultaneously elevate resistance and fracture risk. Higher inflow rates exert effects comparable to a reduced vessel diameter, intensifying resistance and promoting local disturbances. Overall, these findings highlight that clinical application of IVCFs may incorporate imaging data to select filter type and geometry tailored to patient-specific IVC size and flow rate, thereby achieving effective embolus interception while limiting complications.