Retrievable IVC (inferior vena cava) filters are small metal devices that look and function like a cage. They are implanted into the IVC, the largest vein in the human body, in an attempt to catch a blood clot before it is able to reach the lungs, which would be fatal to the patient. While a good system in theory, these devices have now been linked to a number of very serious complications, including migration (where it moves to a different location), organ perforation and breakage.
Why Are IVC Filters Used?
IVC filters are often used as a type of last resort option in patients who have had a blood clot. Normal treatment involves anticoagulant medication, but this doesn’t always work, nor is it always possible. Some patients will continue to develop clots even if they have taken the medication, for instance. Other patients, such as those with an intolerance to anticoagulants or those who have recently experienced trauma, bleeding or surgery, cannot take the medication. In these cases, an IVC filter may be the best option. The first IVC filter was used in 1979, although it was invented much earlier. Since 1979, it has been used more and more regularly, with some 259,000 patients receiving the treatment in 2012 alone.
How Does an IVC Filter Work?
The IVC is the largest vein in the body. It is responsible for transporting deoxygenated blood to the heart and lungs from the lower legs. In order to stop a blood clot from traveling through the IVC into the lungs, an IVC filter may be inserted. The procedure is completed using a thin tube known as a catheter into the IVC, using a small incision in either the groin or the neck. The metal wires on the filter capture and trap any clots before they are able to get to the lungs.
There are a number of permanent IVC filters, but it is the temporary or retrievable filters that are the cause of worries. The removal of these filters is done in the same way as inserting them. First, some x-ray or contrast dye is inserted around the device in order to ensure that it is ready to be removed. Then, a catheter is inserted that includes a snare, which hooks to the top of the filter. It is then covered with a sheath and gently pulled out of the vein.
Problems with Retrievable IVC Filters
A number of potential risks have been found to be associated with IVC filters. These include not being able to actually stop a blood clot from going past the filter and damage to the vein. There are also a number of very serious complications, including the device breaking into pieces and the filter migrating to another part of the body.
The FDA (the U.S. Food and Drug Administration) had released an initial warning about IVC filters in 2012, which was updated in 2015. They had received 921 individual reports of problems with IVC filters between 2005 and 2010. These adverse reports include:
• Filter perforation
• Device migration
• Device embolization (where components detach)
• Filter fracture
About 35% of the problems were related to device migration. This means the device moves out of its original position. The second biggest problem was embolization.
The official FDA recommendation for a retrievable IVC filter is that it should only stay in place between 29 and 54 days. Unfortunately, it now seems that it is being left in place even after there is no longer any risk of a PE (pulmonary embolism).
In 2013, the JAMA (Journal of the American Medical Association) released a report on the failure rate of IVC filters. They studied some 679 retrievable filter cases and found that only 58 of those were removed. It was noted that:
• 18.3% of filters had gone through a failed removal attempt.
• 7.8% of patients suffered a venous thrombotic event.
• 25 patients suffered a PE
IVC Filters That Are Prone to Failure
Studies have revealed that five specific IVC filters are prone to failure. These include three devices by manufacturer Bard, which are the Recovery, the G2 and the G2 Express. The latter two were designed to replace their predecessor, but it seems the issues persisted. The second manufacturer is Cook, whose Gunther Tulip and Celect IVC filters are known to have significant failure rates.
Bard IVC Filter Concerns
Bard has recently revealed to the Securities and Exchange Commission that their Tempe, AZ, and Falls, NY, facilities have received a warning letter from the FDA in relation to misfiling customer complaints. These complaints include manufacturing a removal system without approval, failing to report on a patient death and failing to inform the FDA about malfunctions of their devices. The FDA has declared that they will not approve any Class III, high risk devices to which any of the non-conformance is related.
One of the devices that is under investigation is the Recovery Cone Removal System. This system is used to remove IVC filters from the veins. Model RC-15 is under particular suspicion, as it has not been cleared to be used to remove four different IVC filters. Additionally, model FBRC is in violation of the Federal Food, Drug and Cosmetic Act. This is because it was modified from an existing device and released for commercial distribution without being submitted as a new device, which is a requirement under Section 510(k).
Issues have also been raised about Quality Systems Regulations, particularly at the facility in Tempe, AZ. One issue that has been raised in particular is in relation to the G2 filter. One complaint resulted in a patient’s death but was filed as a medical malfunction. Additionally, many complaint files were incomplete. The Denali IVC filter is also under investigation in relation to its cleaning procedures.
It is also alleged that Bard was well aware of the fact that their devices could lead to complications, but that they marketed it without permission, nevertheless. Further details were uncovered during an NBC News investigation, when it was also found that the company may have forged a signature on clearance applications. When it was denied clearance in 2002, the company hired Kay Fuller, noted recovery specialist. In reviewing the information available to her, she did not agree to sign a new clearance request. To her shock, however, her name and signature have appeared regardless. She has reported this to the FDA, but she does not know whether any action has been taken. To date, some 27 deaths have been reported that could be attributed to Bard’s filters and recovery systems.
The recovery filter, as previously mentioned, was introduced in 2003. Within several months, complication complaints started to pour in. As a result, the company hired Dr. John Lehmann in 2004, who performed an independent study of the device. The Lehmann report showed that the Bard device had higher than usual complication rates and his recommendation was that both the IVC filters and recovery systems should be investigated further. However, this report was not forwarded to the FDA. Rather, they replaced their IVC filter with the G2 model, which turned out to also have a 12% failure rate.
Cook IVC Filter Concerns
Cook has made two specific types of IVC filters that have come under scrutiny. These are the Celect and the Gunther Tulip. Both are metal devices and look almost like a spider. It must be noted that they have performed very well for their intended design on many different occasions. However, there have also been some reports and complaints about very significant issues, and these cannot be denied. Perforation and migration are two specific concerns that have come up very often. As a result, in 2012, the Cardiovascular Interventional Radiology released a report looking specifically at these devices. Shockingly, they found that 100% of the filters perforated within 71 days of being implanted. The FDA recommends that no temporary IVC filter stay in place for longer than 29 to 54 days, but it is also widely known that the majority of filters actually stay in place. This means that virtually anyone who has a Cook filter inserted will also have issues with it. In 40% of cases, the IVC filter had tilted away from the position in which it was inserted, which was the optimal position to be able to collect blood clots.
It is very important to understand that not all IVC filters carry unnecessary risks with them. Naturally, as they involve a surgical procedure, there is always some risk. However, with the above mentioned Bard and Cook models, the risk rate is unacceptably high. Not just that, the risk is often not honestly communicated to the FDA, which means that physicians are not given the opportunity to choose the best course of treatment for their patients, believing instead that their choices are valid.
• Removing Retrievable Inferior Vena Cava Filters: FDA Safety Communication
• C.R. Bard, Inc. 7/13/15
• Bard SEC filing
• Perforation of the IVC: rule rather than exception after longer indwelling times for the Gunther Tulip and Celect retrievable filters
• Initial experience in 115 patients with the retrievable Cook Celect vena cava filter