In a new case study published in the medical journal Baylor University Medical Center Proceedings, doctors from Baylor health centers in Texas warn that inferior vena cava (IVC) filters left implanted for too long can cause a number of complications in patients.

The study provides more evidence concerning the potentially dangerous side effects of IVC filters, such as those made by C.R. Bard and Cook Medical. In May 2014, the FDA published a safety communication noting that IVC filters should be removed as soon as they are no longer needed, optimally within 29-54 days after implantation.

Doctors Warn About Serious IVC Filter Complications

In the study, the doctors note that IVC filters—small, cage-like medical devices—are designed to prevent blood clots in the lungs by trapping those clots before they reach the heart and lungs, and holding them until they dissipate. The devices are usually implanted in patients who are at risk for pulmonary embolism (blood clots in the lung), but for whatever reason, can’t take anticoagulant (blood thinning) drugs, or who aren’t responding as expected to them.

Ongoing monitoring is necessary to determine if the filter is still needed, as long-term complications exist. These complications include the following:

• IVC perforation (the device perforates the inferior vena cava, the main vein traveling from the legs back to the heart and lungs)
• Filter migration to other areas of the body
• Filter fracture or breakage, which can result in pieces embedding themselves into other tissues and organs
• IVC occlusion—where the filter itself causes blood clots

The doctors note that in extreme cases, the filter can cause gastrointestinal hemorrhage and aortic dissection, and that migration of fracture fragments can cause life-threatening arrhythmias and perforation of the heart.

Doctors Find Pieces of the IVC Filter Scattered Throughout the Body

In this case report, a 29-year-old woman who went through a liver transplant was at increased risk for blood clots while in the hospital, so doctors implanted a retrievable Bard G2 IVC filter. (This is the same filter that is now at the center of many IVC filter lawsuits, in which plaintiffs claim to have suffered serious injuries after implantation.)

The woman gradually recovered, and continued to go for follow-up treatments with the transplant clinic. Over six years later, a CT scan of the abdomen and pelvis revealed two filter struts that had broken off the IVC filter and migrated to the area. One was in the abdominal area but hadn’t perforated any organs. The second was lodged in the middle hepatic vein (one of the veins that drain de-oxygenated blood from the liver into the inferior vena cava).

The filter itself was also tilted but not embedded in the vein. Doctors found, however, that multiple struts had perforated the inferior vena cava, with the tips located within the fat of the abdominal cavity. Doctors examined the damage more closely to determine the best way to remove the filter and it’s various parts. Since the patient was no longer at risk for pulmonary embolism, they decided to go ahead with the complicated removal process.

Doctors Recommend Removal of IVC Filters as Soon as Possible

The doctors had to use advanced procedures to completely remove the filter because conventional techniques were unsuccessful. They used nonstandard snare maneuvers, laser-assisted sheath tissue ablation, and microdissection with forceps.

They then wanted to determine how an IVC filter that was initially implanted successfully and in good position could fracture and migrate to the point that it required complicated retrieval. They determined that the “flattening and foreshortening” movements of the IVC itself transmitted to the filter, eventually causing fracture.

The doctors added that a prolonged “dwell time” (time that the filter remains in the body) of over 180 days “has a significant increased risk of complicated retrieval.” As a result of this case, the doctors implemented a new patient database and tracking system to encourage physicians to evaluate patients implanted with IVCs regularly, and to encourage removal as soon as possible.

Currently, there are over 700 Bard IVC filter lawsuits pending in centralized litigation in the District of Arizona, and over 650 Cook IVC filter lawsuits centralized in the Southern District of Indiana.