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 alternative 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.
Even so, IVC filter placement “prevents potentially fatal PE events with a very low risk of complications” when patients are properly selected for the procedure and receive proper follow-up care, according to a 2016 analysis in the journal of Cardiovascular Diagnosis & Therapy.
Complications May or May Not Cause Symptoms
Many patients experience no symptoms when complications arise, and researchers have suggested monitoring to ensure that 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 an incision of approximately 10 inches 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.”
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 retrieval or removal of the filter.
Complications from Placement
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 thread it to the inferior vena cava in the abdomen, using image guidance such as X-ray and ultrasound. This procedure is referred to as percutaneous.
The rate of complications from this procedure has been reported to range from 4 to 11 percent, but most complications are minor and include bleeding at the access site, a blood clot, accidental puncture of an artery and infection. Major complications related to insertion happen less than 1 percent of the time.
Short-Term Placement Complications
Possible procedural risks include the guide wire penetrating the vein as well as bleeding, clots or infection of the insertion site. People can also develop reactions to the contrast agent used during the procedure that can lead to kidney dysfunction, but this is rare.
A rare complication is the formation of an arteriovenous fistula (AVF), which involves an abnormal connection between an artery and a vein. The reported incidence of this complication is 0.02 percent.
As with most percutaneous procedures, filter placement also carries the risk of developing a collapsed lung (pneumothorax) or a collection of blood in between the chest wall and lung (hemothorax). Other complications can include the accidental introduction of air into a blood vessel — an air embolization — and heart rhythm abnormalities.
Access Site Bleeding and Misplacement
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. Patients can also develop blood clots at the insertion site. This is more common in patients who hypercoagulable, meaning they have blood that tends to clot too much.
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. Filters have also been placed in the entirely wrong blood vessel.
Sometimes, filters are placed surgically, rather than percutaneously. Surgically placed filters are more likely to be placed in the wrong spot, or misplaced.
Tilting, Breakage 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.
Certain Filters More Prone to Tilting
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 and blockages of the inferior vena cava, resulting in several deaths.
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 possible open-heart surgery.
Failure to Open and Other Defects
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. A 2016 study in the journal Cardiovascular Diagnosis & Therapy said this failure to open happens between 0.7 percent to 13.9 percent of the time. And with one type of filter — the titanium Greenfield filter — can 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.
Boston Scientific recalled 18,000 Greenfield IVC filters in December 2005. The company said a defect could cause cardiac or pulmonary embolism. It also recalled two lots of filters for possible blood vessel damage in August 2005. Boston Scientific was the first company to issue an IVC filter recall. Since then, Bard, Cordis and B. Braun have recalled more than 63,600 IVC filters for packaging and labeling errors.
Another possible complication is called caval thrombosis, or blood clotting in the vena cava. Rates have been estimated to range 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.
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 that 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.
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 the renal pelvis.
If a patient with a filter experiences non-specific abdominal or back pain, the physician should suspect possible perforation.
Pain Related to Filter Complications
Pain experienced by patients with an IVC filter is often related to complications of the device that may be defective or malfunctioning. Some complications that can cause severe pain include IVC perforation, embolization or a blocked filter.
IVC filters can also become embedded in or perforate the IVC wall. But because blood vessels do not contain nerve endings, it’s unlikely that patients will experience any pain associated to complications directly affecting the vein and they will consequently be unaware of a problem.
However, once an IVC filter has pierced all the way through the vessel, or if it breaks apart moving through the bloodstream, it can affect other areas of the body resulting in pain.
Pain associated with IVC complications can affect the abdomen, back, heart or legs.
Abdominal or Back Pain from Perforation or Migration
Abdominal or back pain associated with an IVC filter is typically due to perforation of the blood vessel and migration of the device or parts of the device to other areas of the body within the abdominal region or the spine.
Perforation and migration account for about 22 percent and 20 percent of all reported complications, respectively.
A case report in 2016, involved a 49-year-old woman who suffered from severe abdominal pain and previous back pain. Her other symptoms included nausea, anorexia, non-bloody vomiting and loose stools (diarrhea). A CT scan showed migration of all four struts of her IVC filter.
The struts had penetrated a nearby blood vessel (the aorta), part of the spine, muscle located adjacent to the lower spine and pelvic region, and tissues located between various organs and the abdominal wall.
Open surgery was needed to remove the IVC filter and repair the patient’s injuries.
Leg Pain Related to Blockage
Leg pain from the device is often due to a blockage. When several clots become trapped in the filter, clot formation down the IVC can cause swelling in the legs, which can be painful.
Other signs and symptoms of a problem might include darkening of the skin and ulceration in the lower extremities.
Patients may have difficulty identifying the cause of the leg pain, apart from the underlying condition of deep vein thrombosis (DVT) for which they are being treated. Any leg pain that is severe or worsens suddenly or over time, should be evaluated by a doctor.
Detachment Risks to Heart and Lungs
When a strut breaks loose and makes its’ way through the bloodstream to the heart or lungs, called embolization, patients can suffer from severe chest pain similar to a heart attack.
Adverse event reports submitted to the U.S Food and Drug Administration (FDA) between 2005 and 2010, included 146 reports of embolization out of 921 total reports.
Embolization of IVC filters to the heart and lungs can have serious and sometimes deadly consequences. Signs and symptoms of the serious condition might include coughing up blood, heart attack, swelling in the legs, difficulty breathing or shortness of breath, and loss of consciousness.
A 2008 case study in the Texas Heart Institute Journal describes a 69-year-old patient who was implanted with an IVC filter, which ended up moving to the right ventricle of his heart. His primary symptom was a ventricular tachycardia, an elevated heartbeat arising from the lower chamber of the heart. A person’s heartbeat normally arises from the right atrium, which is the top part of the heart.
After the device was removed, he developed a leaky tricuspid valve in his right heart chamber. His doctors believed the device had become entangled in the valve, which sustain damaged when the device was removed.
In some cases, open heart surgery may be needed to repair damage caused by IVC filter embolization to the heart.
DVTs and Retrieval Risks
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.
Please seek the advice of a medical professional before making health care decisions.