Hemodynamic analysis of fusiform-shaped inferior vena cava filter with thrombus capture: A computational fluid dynamics study

The placement of an inferior vena cava filter (IVCF) has been an effective treatment to prevent fatal pulmonary embolism in clinical practice for decades. Fusiform-shaped filter is one of the main types of IVCFs, but its hemodynamics with thrombus capture has not been clearly understood. In this paper, computational fluid dynamics (CFD) simulations are used to investigate the characteristics of blood flow with thrombi over TrapEase and OptEase filters, respectively, two frequently used fusiform-shaped IVCFs in clinic therapy. The blood flow with thrombi is characterized by the Eulerian two-phase flow model, in which the blood is regarded as a non-Newtonian fluid. CFD results show that there are significant stagnation zones downstream of both filters, with the lengths nearly up to 12 times the diameter of the IVC. The no-slip wall conditions of filter wires induce a viscous block effect and result in blood flow acceleration inside the fusiform-shaped filter. The viscous drag contributes predominantly to the total flow resistance of fusiform-shaped filter, about three times the pressure drag. The presence of thrombi does not greatly affect the hemodynamics, but reduces the nearby blood flow speed when captured by the filter. The thrombi primarily accumulate at the end of the filter, increasing both viscous and pressure drag, leading to a 10%-12% increase in total flow resistance. The present study provides common insights into the hemodynamics with thrombus capture of the fusiform-shaped filter, which would contribute to its future clinical use and design improvement.