What is a DVT and PE?
Blood clots can form in the veins of the legs and pelvis (a condition known as deep vein thrombosis or DVT), and can travel from there to the lungs, causing difficulty in breathing, and sometimes death.
The purpose of a vena cava filter is to capture such blood clots (also known as emboli) within the largest vein of the abdomen (the inferior vena cava or IVC) before they can reach the heart or lungs. Older IVC filters were designed to be permanently left in place, but newer types of filters are designed to be either removable or permanent. These newer filters are referred to as optional filters.
An IVC filter may be used in patients felt to have an ongoing risk of deep vein thrombosis and pulmonary emboli, particularly if blood thinning medications are not effective or dangerous. The need for an IVC filter may be temporary, such as around the time of childbirth or surgery, when either the risk of DVT or the danger from blood thinning medications is temporary. In such situations the option of being able to remove the IVC filter may be preferred.
How should I prepare?
Before the procedure, you may have blood tested to determine how well your kidneys and your blood clotting are functioning. You should inform your doctor of all medications you are taking, including any herbal supplements. Inform us of any allergies, particularly to local or general anesthetic medications or to contrast materials (sometimes called X-ray dye) or to latex gloves. Always inform your doctor if you are or may be pregnant.
Eat a light meal the evening before. You may be instructed not to eat or drink after midnight before the procedure, and if you are diabetic you should receive instructions from your doctor about adjusting medications and insulin dose on the day of the procedure. You will be asked to remove your clothing and wear a gown during the procedure. You will need a ride home with a friend or relative.
How is the procedure performed?
The procedure will take place in a radiologic operating room, on a specialized table to permit the use of real-time X-rays (called fluoroscopy). The patient lies their back, covered with a sterile drape and attached to devices to monitor heart rate and blood pressure. Sterile techniques will be used to prevent infection, including cleaning and shaving the skin directly over the large vein of the neck or the groin where the IVC filter will be introduced or removed. After a local anesthetic is administered, a very thin plastic tube (a catheter) is advanced into the IVC, guided by fluoroscopy. An injection of contrast will usually be done to be certain of the correct position when placing the IVC filter, but this is not usually necessary when removing an IVC filter.
What will I experience during and after the procedure?
If sedation is used, the medications will make you feel relaxed or sleepy. The local anesthetic usually stings, but after that the puncture site will be numb. The injection of contrast may give a very brief, warm sensation within your body. After the procedure, you will be observed in a recovery room until you are ready to return home.
How will I get my results?
The interventional radiologist will inform you whether the procedure was technically successful when it is complete.
What are the benefits and risks?
The procedure is done without surgery.
IVC filters have a high rate of preventing serious pulmonary embolus, even in patients where conventional treatments have failed or cannot be used. Any procedure requiring placing a catheter into a blood vessel carries small risks of damage to the blood vessel, bruising or bleeding at the puncture site, or infection.
Allergy to contrast material is very uncommon.
There is a very small chance that the IVC filter may land in the wrong place, change its position over time, or penetrate through the vein (rarely leading to damage of adjacent organs). Rarely, the filter or a piece of the filter may break loose and travel to the heart or lungs, causing injury or death. Rarely, IVC filters become so filled with blood clots that they completely block the vena cava, causing long-lasting swelling of both legs.
In some cases, an optional filter may be unable to be removed for various technical reasons. The filters are designed so they may be left in permanently.
Radiologyinfo.org for Patients
The radiology information resource for patients. RadiologyInfo.org tells you how various X-ray, CT, MRI, ultrasound, radiation therapy and other procedures are performed. It also addresses what you may experience and how to prepare for the exams. The website contains over 200 procedure, exam and disease descriptions covering diagnostic and interventional radiology, nuclear medicine, radiation therapy and radiation safety and is updated frequently with new information. All material on the RadiologyInfo.org website is reviewed and approved by experts in the field of radiology from the ACR and RSNA, as well as other professional radiology organizations.