A Physiologic In Vitro Model of the Inferior Vena Cava with a Computer-Controlled Flow System for Testing of Inferior Vena Cava Filters

RATIONALE AND OBJECTIVES The authors develop a physiologic in vitro model of the inferior vena cava (IVC) for testing of filters. METHODS The model is driven by a centrifugal pump. A computer-controlled electromagnetic valve is used for generation of different flow patterns. Limitation of the pressure increase in case of IVC occlusion is achieved by a bypass circuit. A glycerin solution is used for perfusion. Artificial clots are made from polyacrylamide gel. Data acquisition includes continuous monitoring of flow and difference pressure over the filter and video recording of the testing events. RESULTS The model can generate constant and pulsatile flows. The pressure increase can be limited to 70 mm Hg in case of occlusion. Calculation of the flow velocities in the IVC is possible. A classification of thrombus capturing is presented. The testing of most of the results are reproducible. CONCLUSIONS The in vitro model simulates the physiologic conditions in the IVC. It can be used for comparative testing of different filters and the evaluation of new filter designs.