Computational Flow Study of a Simon Nitinol® Inferior Vena Cava Filter

More than 60,000 people die from pulmonary embolism every year in the US. Conventional treatments for embolisms include anti-coagulant drugs (Warfarin® or Heparin®), clot anti-thrombotic therapy (streptokinase®), bypass surgery, and thrombo-aspiration. In cases where the patient shows contraindication, failure or complication to anticoagulation drugs, the patient usually receives an inferior vena cava filter (IVCF). 8. Despite its increase in popularity, complete and exhaustive blood flow analysis need to be performed for scenarios that can lead to IVCFs failure. Such scenarios include basket over-filling and filter tilting, among others. In this study, we wanted to compare the behavior of blood flow as it travels through the Simon Nitinol® IVCF with and without occlusions. All simulations wereperformed using ANSYS CFX. The inlet’s normal velocity was set to 5 cm/s. For the outlet, zerorelative pressure was prescribed. The walls of the vessel were constrained to no-slip conditions. Aviscosity of 3.5 centipoise and density of 1125 kg/m3 were utilized for the blood’s properties. Allsolutions were set to converge at 10-4 error margin for the momentum and continuity equations. As the occlusion size increased, the velocity of the blood flow increased proportionally. The velocity of blood flow was different in certain parts of the filter as seen in fig. 1. The spikes in the graphs represent the blood flowing through the first and second traps of the filter. The peak velocity occurred where there is less distance from parts of the filter to the wall. For future work, we will add occlusions for all of the filters in order to determine which filter is best for trapping blood clots. We will also incorporate a more realistic vessel wall. These studies will help design IVCFs with superior performance.