Design Of A New Vena Cava Filter And Studies On Its Hemodynamic Performance By Computational Simulation

Pulmonary embolism (PE) is a common complication among patient in the intensive care unit. While anticoagulation remains as the standard therapy, vena cava filters (VCFs) are important alternatives when anticoagulation is contraindicated or failed. VCFs use kinds of filters to trap thrombus, especially big sized ones, keeping them away from the pulmonary circulation, and prohibiting the occurrence of PE. Up to now, different measures have been taken to reduce the complications of VCF and promote their performances. As a result, many VCFs with better and better performance are emerged and the utilization of the device has become wider and wider. Nonetheless, even with their potential, VCFs' design is by no means a mature process and still has large room for improvement.While VCFs have been successfully used in clinic, they are still suffering major failures due to the deployment of the device and the build up of new thrombus in the filters themselves. Clinical studies indicate that there are different kinds of thrombus complications after the deployment of VCF: 1) insertion-site thrombosis; 2) access-site thrombosis; 3) filter blockage caused by the trapped thrombus. Many ways have been tried to reduce these complications, such as facilitating the percutaneous insertion with a small size introducer for the filter to reduce the insertion-site thrombosis. In these ways, short- and long-term complications would be minimal and potential emboli above a reasonably defined size would be prevented without impedance of vena cava flow.Now, it has been well documented that the alteration of vena cava blood flow pattern due to the installation of VCF may result in thrombus complications. Therefore, blood flow itself should be taken into consideration in the design of VCFs in order to reduce these complications after the deployment of VCF and facilitate the lysis of trapped clots.This dissertation proposed a vena cava filter with a new concept in which spiral flows are introduced in the filter's working zone to minimize filter blockage by the trapped clots and facilitate the lysis of trapped clots.Using Computer Assistant Design (CAD), 2 different types of VCF models with spiral flows were designed and manufactured. Then, the 3-dimensional flow patterns of the VCF models were studied using computational simulation with a Fluent software package. The performances of the filter devices with or without spiral flow were...