The inferior vena cava (“IVC” or “vena cava”) is the vein that brings de-oxygenated blood cells from the legs and hips to the right atrium, then finally to the lungs. Notably, the inferior vena cava is the largest vein in the human body, and has disproportionately thin walls because of the decreased pressure generated by venous blood
An inferior vena cava filter is a small umbrella-shaped or cone-like device that is implanted within the inferior vena cava. And similar to an umbrella, it has several metallic wires that branch off from the top in a downward angle. These wires, also called struts, arms, or legs, collectively act as a blocking mechanism that prevents blood clots from passing and moving upward toward the heart and lungs. Now, to get a deeper understanding of the purpose and functionality of an IVC filter, it would help to continue getting a better understanding the inferior vena cava.
The vena cava develops where the common iliac veins at the top side of the pelvic cavity meet to form a larger vein. From this point the vena cava rises from the pelvic area through the abdomen. Here, it receives blood from the inferior phrenic, suprarenal, renal, and gonadal veins. Additional blood pours into the vena cava from digestive organs by way of the hepatic vein, and tissues from the lower back. Finally, several smaller veins from the abdominal wall contribute blood to the vena cava.
Sources of blood contributing to the vena cava below the pelvic area include tributaries from the feet, legs, and thighs. In order for the blood to move upward from theses lower extremities, the body uses one-way venous valves, contraction of the skeletal muscles in the legs, and pressure and blood-trapping from venous veins in the abdomen. See Tim Taylor, Anatomy and Physiology Instructor, InnerBody.com (http://www.innerbody.com/image_dige07/card26.html).
Thus, the filter is engineered to catch blood clots that rise from the lower extremities, such as the veins in the feet, ankles, knees, upper legs, and upwards to the heart and lungs.
Inferior vena cava filters (“IVC filters ”) are typically implanted by vascular surgeons or interventional radiologists as a method of stopping blood clots from passing all the way through the vena cava. If that were to occur then it could lead to a pulmonary embolism.
Overall, IVC filters are developed to capture blood clots and preserve normal blood flow within the IVC.