Hemodynamic Simulation Of Vena Tech Convertible Filter

Objective:To simulate the blood flow in inferior vena cava(IVC)by computational fluid dynamics(CFD).To investigate the influence of the placement of the VenaTech Convertible filter in the IVC,to study the changes of the hemodynamic characteristics of the filters with different degrees of tension,to determine the areas that may have an impact on the thrombosis in the filter,and to predict the prognosis of the long-term indwelling of the filter in vivo.Methods:Computational Fluid Dynamics(CFD)was used to simulate hemodynamics in a 20 mm diameter inferior vena cava model.The hemodynamic characteristics of VenaTech Convertible filter was evaluated under steady flow(Re = 368.7).The velocity distribution in the inferior vena cava and the shear stress distribution on the wall of the vessel and the surface of the filter wire were sampled and analyzed.Results:The results showed that the middle blood flow accelerated,the shear force on the surface of the filter wire increased,the shear force on the surface of the vascular wall gradually increased,the blood flow at the junction of the vascular wall and the filter wire was slow,the shear forcewas small,and there was a small area of stagnation;when placed in the opposite direction,the blood flow diverged to the surrounding area,the blood flow around the filter accelerated,the shear force on the surface of the filter wire was uniform,and the shear force on the surface of the vascular wall was uniform.When the filter filament is close to each other,there is a long slow flow zone behind the filter.When the filter transforms into a non-filter one,the larger the tension angle,the closer the blood flow pattern is to the non-filter one,and a small stagnation zone can be formed between the filter wire and the vascular wall.Conclusion : VenaTech Convertible filters can cause hemodynamic changes in the inferior vena cava.The flow rate around the filters,the WSS of the filters and the surface of the vessel wall can be changed by placing the filters in the opposite direction.When the filter is not fully opened after conversion,or the low-speed or stagnant area formed by the filter is not converted may lead to thrombosis,which needs further clinical verification.