Inferior vena cava (IVC) filters are devices that are placed in the largest vein in the body with the intention of trapping clots before they reach the lungs. Since the early 2000s, retrievable IVC filters have been an option in addition to permanent filters.
The FDA has received reports of adverse events linked to the filters, including filter fracture, movement of the filter or fragments to the heart or lungs, perforation, and trouble removing the IVC.
Researchers say that advancements in filter design have reduced the number of complications, but because many complications involve no symptoms, it’s not known exactly how prevalent they are.
IVC Filter Complications With or Without Symptoms
Many patients experience no symptoms when complications arise, and researchers have suggested monitoring to ensure the filters remain in place and are doing what they’re supposed to. In some instances, the side effects can be painful and dangerous.
“It’s like a knife being pushed into your stomach,” one patient told a television reporter about the experience of having her IVCs filter twist and puncture the walls of the artery where it had been implanted three years earlier.
Clare Austin of South Florida said surgeons had to make, approximately, a 10-inch incision in her belly to remove the filter.
“When I woke up I was in horrendous pain. A few days later when I finally saw the incision that was unbelievable”
- Clare Austin, IVC Filter recipient
As a general rule, IVC filter complications are grouped into three categories: those that occur during placement, those problems with the filters that happen after placement and complications during removal or retrieval of the filter.
IVC Filter Placement Complications
To place the filter, a doctor will usually use a catheter inserted through the skin into a large vein in the neck or thigh and threaded to the inferior vena cava in the abdomen. The filter is threaded through the catheter into the vein, using image guidance, including X-ray and ultrasound and a contrast agent, or a substance introduced into the body to help the medical professionals see. This procedure is referred to as percutaneous.
The rate of complications from this procedure has been reported to range from 4 to 11 percent.
Short-Term Complications from Placement
Short-term complications related to this procedure can include:
- Reaction to the contrast agent
- Abnormal or irregular heartbeat
- Air embolization (bubbles of air blocking a blood vessel)
- Pneumothorax (a collapsed lung caused by air leaking into the space between the lung and chest wall)
- Hemothorax, which is a collection of blood in the space between the chest wall and the lung
Other possible complications of the procedure include the guide wire penetrating the vein, bleeding or infection of the insertion site, kidney dysfunction caused by the contrast agent, blood clotting at the insertion site and a condition called arteriovenous fistula (AVF), which is a rare complication involving an abnormal connection between an artery and a vein. The reported incidence of this complication is 0.02 percent.
Access Site Bleeding
The rate of bleeding at the access site is estimated between 6 and 15 percent. But significant bleeding that would require a transfusion or surgery is rare. Blood clots at the site range from 2 to 35 percent, with higher rates in patients with blood that tends to clot too much. The studies that found higher rates used ultrasound and found clotting in patients without symptoms.
IVC filters are more often incorrectly positioned when they are implanted during a surgical procedure.
In a few cases, medical professionals have incorrectly oriented the filter. In one instance, a filter was put in backwards and had to be retrieved.
Sometimes, filters are placed surgically, rather than percutaneously – a medical procedure performed through the skin rather than an open approach with exposed organs or tissue. When this is done, filters are more likely to be placed in the wrong spot, or misplaced.
IVC Filter Tilting and Migration
Other complications relate to problems with the filter itself. For example, the filter might fail to completely open, it may tilt or be placed in the wrong location. The filter may also fracture or migrate to another location in the body.
IVC Filter Tilt
Medical professionals define tilt as occurring when the filter is angled at greater than 15 degrees. When this happens, patients are at greater risk of pulmonary embolism. This has been found by researchers most commonly with particular filters: Recovery/G2 made by Bard Peripheral Vascular and Günther-Tulip from Fort Wayne Metals.
Researchers disagree on the best way to treat patients whose filters have tilted, with options including retrieval, adjustment and placement of a second filter. The first option can lead to other problems, such as the filter becoming embedded or perforating the vein. Trying to adjust the placement is not recommended by manufacturers. And the placement of a second filter isn’t supported in research literature. Another option is for the doctor to closely monitor the patient and filter.
IVC Filter Migration
Medical professionals consider a filter to have significantly migrated if it moves 2 centimeters or more from the initial location. This can happen for several reasons, including the filter being too small and the patient having a catheter. One filter, the Mobin-Uddin, was discontinued in 1986 after being associated with high rates of migration, resulting in several deaths.
Experts report that incidents of filter migration happen 9 out of 10 times within a month after implantation.
Newer filters have much lower migration levels, estimated at less than 1 percent. Researchers say 90 percent of migration incidents happened more than 30 days after placement.
Migration has been found twice as often with permanent filters as with retrievable filters. When migration into the cardiopulmonary system happens, it can be fatal, and it requires immediate medical intervention, including possibly open-heart surgery.
Defective IVC Filters
Sometimes the filter is defective and fails to open completely. This also can happen for other reasons, including an error on the part of the doctor who places the filter. This failure to open happens between 0.7 percent to 13.9 percent of the time, with one type of filter — the titanium Greenfield filter — having this happen in as many as 71 percent of cases. When this happens, the filter’s performance can be decreased by as much as 80 percent, especially for catching smaller clots.
Another possible complication is called caval thrombosis, or blood clotting in the vena cava. Rates have been estimated ranging between 2 percent to 30 percent. When there are symptoms, they include pain and swelling in the lower extremities. The cause isn’t known, but can be related to the fact that patients already have higher risk for clotting, as well as the increased clotting from the presence of a foreign body in the vena cava. It may also represent clots that have been captured by the filter, as intended.
IVC Filter Fracture and Perforation
Filter fracture is a late complication, usually seen in filters that have been in place for more than a year. Researchers suggest this may mean that the structure of the filter wears down over time. Consequently, promptly removing retrievable filters after they are no longer needed can prevent this complication from happening.
Vein perforation happens more often when IVC filters are left in place for too long.
In one study, researchers looked at 80 patients who had two particular brands of filters placed in them between 2004 and 2009, the Bard Recovery and the Bard G2 filters. A total of 13, or 16 percent of the patients had at least one of their filters’ struts fracture. In five cases, the strut had lodged in the patients’ hearts. Three of the patients had life-threatening conditions.
Sometimes the filter perforates the vein. This happens more often with retrievable filters that have been left in place longer than intended. Serious, but rare cases, have involved perforation of the duodenum, the aorta and renal pelvis.
If a patient with a filter experiences non-specific abdominal or back pain, the physician should suspect possible perforation.
Other IVC Filter Complications
Patients with IVC filters have a risk of deep venous thrombosis (blood clot in lower-body vein). The risk doubles two years after a filter is placed. The incidence of this complication has been estimated to be as high as 43 percent.
Retrieving the filter comes with possible problems, including fracturing the filter and injuring the inferior vena cava, tearing the wall of the blood vessel or hemorrhage.
Despite the possibility of complications from the removal procedure, experts still recommend removing the IVC filter as soon as it’s no longer needed because the risks of leaving it in place too long outweigh the risks of removing it.
Elaine Silvestrini is a career journalist with a strong desire to learn, explain, and help people. At Drugwatch, Elaine has reported about trials over whether talcum powder caused ovarian cancer and allegations that Androgel causes heart problems in patients who use it. She has chronicled the billions of dollars generated for big pharmaceutical companies by certain drugs and efforts to warn consumers about the dangers of specific medical problems. Elaine has received six health literacy certificates for completing courses offered by the Centers for Disease Control and Prevention. She brings more than 20 years of experience covering state and federal court systems, learning the intricacies of criminal and civil law, developing investigative pieces about how the law affects people’s lives and digging through and digesting reams of court records on a daily basis.