- 1 Retrievable inferior vena cava filters are small, cage-like metal devices implanted in the veins of patients to catch blood clots before they reach the lungs. But the devices are linked to a number of complications like vein and organ perforation, migration and breakage that can injure patients.
- 2 How Does an IVC Filter Work?
- 3 Complications with Retrievable IVC Filter
- 4 IVC Filter Studies Confirm FDA Safety Warnings
The device was introduced in 1979, and its use increased continuously through the years. By 2012, doctors inserted approximately 259,000 of them in patients.
Blood clots that develop deep inside the pelvis, lower and upper extremities are referred to as deep venous thrombosis, or DVTs. Generally, DVTs are not life-threatening. However, these clots can cause death when one or more travel to the lungs and become a pulmonary embolism (PE). PEs cut off the normal blood flow to a person’s lungs, and they cause about 300,000 deaths a year – the third-most common cause of death (and one of the most preventable) in hospital patients.
Some filter products designed to stave off the traveling of blood clots work better than others, according to medical studies. Evidence shows some products migrate away from their surgically positioned location, which can render them ineffective. Another documented shortcoming is that the device itself can puncture a vein, causing bleeding and other complications. Surgeons place the filters with the best intentions but keep an eye out for issues that can stem from filter procedures.
How Does an IVC Filter Work?
The inferior vena cava is the largest vein in someone’s body and moves de-oxygenated blood from the lower legs to the heart’s right atrium and, later, to the lungs. To prevent blood clots from traveling that route into the lungs, doctors implant an IVC filter into the vein.
A vascular surgeon, interventional cardiologist or interventional radiologist inserts the device using a catheter into a patient’s inferior vena cava through a small incision in the neck or groin. The inferior vena cava is a large vein below the kidneys. Its job is to return blood back to the heart. Metal wires capture and trap blood clots before they can reach the lungs.
When the filter’s job is done or when it’s no longer needed, doctors remove it in a similar way. Healthcare providers inject contrast or X-ray dye around the device to make sure it is safe to proceed with the removal. A catheter-like snare does into the vein and grabs the hook located at the end of the filter. The filter is then covered by a sheath and pulled out of the vein.
Depending on the manufacturer, the IVC filter may have multiple spokes or thin rods. At the other end of the filter, a metal cap captures the blood clot. Over time, the body’s natural anticoagulants break down the clot.
There are two types of IVC filters:
- Optional, or retrievable
Retrievable filters provide short-term protection. They’re designed to be removed from a patient’s body when they are no longer at risk for PE. Unfortunately, these are also the type involved in lawsuits because of complications like blood vessel and organ perforation, filter migration and devices breaking inside patients.
Good candidates for filter implantation:
- People who had recurrent VTE while on anticoagulation medication
- People who can’t tolerate or consume anticoagulation because of an adverse reaction, bleeding, trauma or recent surgery
Although companies designed IVCs to help prevent PE, these devices can also cause serious complications.
Complications with Retrievable IVC Filter
Risks associated with filter implantation include a damaged vein and blood clots forming and bypassing the device. However, serious complications can occur because of the implanted filters. One of the most serious is the device breaking apart and traveling to another area of the body.
In 2010, the FDA announced a safety alert regarding retrievable IFC filters. Starting in 2005, the FDA received 921 reports of adverse events occurring with the filters. Events involved:
- Device migration
- Filter perforation
- Filter fracture
- Detached device components (called device embolization)
A majority of the adverse events, 328 – or 35.6 percent – involved device migration. That occurs when filters move away from where they were placed. The FDA listed embolization as the second most frequently reported complication.
Retrievable IVC filters are only intended for short-term placement. However, the FDA is concerned the devices are staying in patients long after the PE risk subsides.
IVC Filter Studies Confirm FDA Safety Warnings
Research studies confirm the problems with retrievable IVC filters. A 2013 research study in the Journal of American Medical Association, or JAMA, looked at the filter’s failure. It reviewed medical records of a level 1 trauma center for the indications, complications and management of the IVC filters. It determined physicians were not removing the filters.
Researchers discovered only 58 out of 679 retrievable IVC filters inserted were actually removed. Other results discovered majority of the filters remained in patients longer than medically necessary with the following results:
18.3 percent failed attempts at removing the filters.
7.8 percent had venous thrombotic events. Approximately 25 of those events were PE. The term “events” means a patient developed some kind of medical condition.
An Archives of Internal Medicine study revealed two retrievable IVC filters prone to failure:
- Bard Recovery filter
- Bard G2 Filter
The Recovery filter was Bard’s the first-generation of this product and was introduced in 2003. A second generation device, Bard G2, arrived in 2005 as a replacement for the Recovery. Results from a study of Bard retrievable vena cava filters published in 2010 in JAMA Internal medicine show a about 25 percent of the Recovery filters failed causing the device to fracture or break apart. One patient died at home, although the study does not explain the reason. The Bard G2 had a 12 percent failure rate. The study noted the second-generation retrievable IVC filter remained on the market a shorter amount of time than its predecessor.
A 2012 research study published in the CardioVascular Interventional Radiology indicated two other manufacturers had retrievable IVC filters that failed. All of the filters made by Gunther Tulip and Cook Celect perforated patients’ vena cava wall – a vein puncture. The perforation occurred within 71 days of implantation, and filters also migrated out of place in 40 percent of patients.
Because of these complications, injured patients filed lawsuits against IVC filter makers. In court documents, plaintiffs allege filters migrate and break apart causing organ damage and other complications.