What Are IVC Filters?
An IVC filter is a small medical device inserted into the inferior vena cava (IVC), the largest vein in the body, to prevent potentially fatal blood clots that sometimes occur after surgery or injuries. They are most commonly used in people at risk of pulmonary embolism or deep vein thrombosis (DVT) when prescription blood thinners are not a viable option.
IVC Filter Complications
Approved by the United States Food and Drug Administration (FDA) in 1979, IVC filters are now available as permanent or retrievable implants, with the retrievable option intended for short-term use. From 2005 to 2010, the FDA received nearly 1,000 complaints regarding adverse events connected to the failure of the newer retrievable filters and IVC filter removal complications.
The FDA did not report on the remaining 34.8% of adverse event reports, but did issue a warning regarding an increased risk of IVC DVT. In light of these reports, the agency began advising doctors to remove retrievable IVC filters once the threat of pulmonary embolism was no longer present.
Unfortunately, many of the worst complications were experienced upon the removal of the retrievable filters. Few were due to the implantation procedure, or the presence of the device in the body.
IVC filter complications typically fall into three categories: procedural, delayed, and retrieval. The following risks are well documented, but complications can vary significantly between patients.
IVC Filter Complications by Category
|Procedural Complications||Delayed Complications||Retrieval Complications|
IVC Filter Migration & Embolization
While older IVC filters were made of titanium or stainless steel, the newer retrievable devices are created using a variety of high-tech alloys. Since these filters become flexible with temperature changes, fluctuations in body temperature can alter the device’s configuration, allowing it to detach.
If the filter detaches from the IVC’s walls, it can migrate to other parts of the IVC, the heart, or other organs. During this migration (also known as embolization) the device is carried “upstream” with the blood flow, moving through the body and often perforating everything in its path.
Migration & embolization symptoms can include:
- Abnormal heart rhythms
- Chest pain
People with migrated IVC filters are considered at high risk for serious complications like ventricular arrhythmia (rapid heart rhythms) and cardiac tamponade, a potentially fatal medical emergency where blood escapes into the gap between the heart muscle and outer layer. For example, in 2009, cardiologists at Michigan’s William Beaumont Hospital documented the case of a 54-year-old man whose retrievable IVC filter migrated to his heart. As a result, he was diagnosed with non-Q-wave myocardial infarction, a type of heart attack.
IVC Filter Fractures
Many sources, including the FDA, have reported that there’s a trend toward doctors leaving retrievable IVC filters in for too long, increasing the risk of device failure over time. In fact, a 2014 study published in the Journal of Vascular Surgery reported that retrievable IVC filters left in place for extended periods are associated with significantly higher complication rates than permanent filters. The FDA’s adverse event reports from 2005 to 2010 included 202 filter fractures. 146 of these instances involved broken pieces migrating toward the heart. The disseminated pieces are extremely difficult to extract during the removal procedure.
In 2010, York Hospital in Pennsylvania examined 80 patients with filters manufactured by C.R. Bard, a New Jersey company that now faces a number of IVC filter lawsuits. Their results, published in the Journal of the American Medical Association, revealed some troubling statistics:
- 16% had at least one fractured filter strut
- 25% experienced embolized fragments beginning to flow to the heart
- 71% with embolized fragments had a broken strut that had already entered the heart
- 43% suffered life-threatening symptoms, including sudden death
Throughout the implantation, general presence, and removal process of the IVC filter, the device has been shown to cause perforations that can lead to potentially life-threatening situations. The FDA reported 70 adverse event reports between 2005 and 2010 in which some degree of perforation had occurred. Once a strut has punctured the vessel wall, the sharp wire is likely to pierce surrounding tissues and organs. Since IVC filters are typically placed near the kidneys, the intestines and ureter are often damaged, along with other blood vessels in the area.
The primary IVC filter complications associated with perforation include:
- Retroperitoneal hematoma: a swollen clot of blood within body tissues of the abdominal cavity
- Sepsis: a bodily reaction to an infection that releases chemicals into the bloodstream, triggering inflammation, and potentially leading to systemic organ failure, shock, and death
- Gastrointestinal bleeding: a complication that can cause anemia and low blood counts
IVC Filter Thrombosis
IVC filters have also been shown to cause blood clots, the serious condition that they were designed to treat. When a blood clot forms in the IVC, the flow of deoxygenated blood may be blocked from reaching the heart, causing IVC thrombosis, a subtype of DVT. IVC thrombosis is associated with a number of serious symptoms and can lead to other conditions, including:
- Lower back pain
- Painful swellings in the legs
- Pulmonary embolism
Other IVC Filter Side Effects
The FDA has also found less serious IVC side effects, including irregular heartbeat, chest pains, and breathlessness, often resulting in the loss of consciousness.
In light of the widespread acknowledgment of IVC filter removal complications and significant filter risks, patients have started filing lawsuits against C.R. Bard and Cook Medical, the primary manufacturers of these devices. To learn more about IVC filter complication lawsuits, visit the dedicated tab.
Purpose of IVC Filters
In some cases, blood clots can form in the leg’s “deep” veins (that is, veins located deep within the body as opposed to near the skin’s surface). These clots, also known as embolisms, can break off and travel through the blood stream to the lungs, where they can create a life-threatening condition known as pulmonary embolism. Such clots tend to form after surgeries on the lower extremities, such as to insert knee replacement devices.
IVC filters are designed to capture blood clots that form in the inferior vena cava, the largest vein in the body, thereby preventing them from reaching the lungs. The IVC filter is a small, cage-like metal device shaped like a cone, and it is typically implanted in the IVC just beneath the kidneys. The filter allows blood to flow regularly through the filter while trapping the blood clot. In time, naturally-occurring blood thinners help break down the clot, thereby eliminating the danger of pulmonary embolism.
IVC filters are generally implanted in people that experience pulmonary embolisms or deep vein thrombosis (DVT) despite the regular and monitored use of prescribed anticoagulants. In less common cases, patients who are unable to take prescription blood thinners like Xarelto or Pradaxa are also candidates for IVC filters. The filters are generally designed to be permanent implants.
IVC Filter Safety Concerns
Initially intended to be permanent implants, the Food and Drug Administration (FDA) began recommending in 2010 that IVC filters be removed as soon as the risk for pulmonary embolism has passed and the patient can withstand the removal surgery. From 2005 to 2010, the FDA received nearly a thousand complaints regarding several serious and less severe issues related to IVC filters.
Most complaints seem to be related to long-term use of IVC filters. For example, some patients experienced pieces of their filter breaking off and traveling through the bloodstream, while others have had their filters migrate entirely from their original position. Depending on the severity of the movement, IVC filter can cause perforations in a blood vessel or organ, causing serious pain and damage to the body.
IVC Filter Lawsuits
Many individual and class-action IVC filter lawsuits have been brought against manufacturers of the devices. At least one major manufacturer, Cook Medical Inc., has a pending multi-district litigation. The U.S. District Court for the Southern District of Indiana is overseeing the multidistrict litigation No. 2570.