The migration of an IVC filter after it has been implanted is the most dangerous medical complication associated with the device. When an IVC filter migrates, it can lodge in the patient's heart, causing life-threatening complications. Migrations often happen after the filter has fractured or broken, with each piece of the device posing a threat. Finally, IVC filters that have migrated are powerless to stop a blood clot from traveling to the lungs and causing a pulmonary embolism. Because of the dangers caused by device migrations, they form a core group of the IVC filter lawsuits that have been filed.
- 1. How IVC filters can migrate
- 2. Medical complications caused by migrating IVC filters
- 3. Symptoms that an IVC filter has migrated
1. How IVC filters can migrate
An IVC filter migrates if it dislodges from where it was implanted and moves away.
IVC filters are tiny medical devices that are implanted in a patient's inferior vena cava vein, which brings blood from a patient's legs up to their lungs and heart. IVC filters are implanted to stop blood clots from traveling up this vein and to the lungs, where they could block arteries and cause a potentially fatal pulmonary embolism.
An IVC filter looks like the frame of a tiny umbrella. The protruding legs are called “struts,” while the centerpiece is called the “head.” With the struts closed, the IVC filter is inserted through an incision in the patient's neck or groin. It is then navigated to the inferior vena cava using a catheter, where the struts are opened.
If the struts are opened too far, they can perforate the interior walls of the vein and cause medical complications. However, if they are not opened far enough, the IVC filter does not gain a strong enough foothold to stay in place, and is likely to dislodge and migrate.
The longer the IVC filter is in place, the more stress it is put through. The inferior vena cava is surrounded by organs and tissues, so it gets jostled and pushed by heartbeats, breathing, and even mundane upper body movements. While seemingly insignificant, this trauma can break or fracture the fragile struts of the IVC filter.
To make matters worse, most IVC filters that are implanted are meant to be temporary solutions, and are prone to deterioration if left inside a patient for a long period of time. According to the U.S. Food and Drug Administration (FDA), IVC filters should be removed from a patient as soon as the risks of a pulmonary embolism have passed.1 One study has shown that the risks of an implanted IVC filter surpass the benefits between 29 and 54 days after being implanted.2
Together, the trauma that IVC filters endure and their slow deterioration over time create their tendency to fracture and break inside the inferior vena cava vein. If the filter fractures, the piece that has broken off is likely to dislodge and migrate: More than a third of the 921 adverse events involving IVC filters reported to the FDA between 2005 and 2010 involved migrating filters.3 Nearly all migrations happen more than a month after the initial implantation.4
2. Medical complications caused by migrating IVC filters
An IVC filter that has migrated from where it was implanted can cause serious medical complications, depending on where it goes.
Because of the flow of blood from the legs to the heart and lungs, migrating IVC filters tend to travel to the heart. Once there, a migrated IVC filter can cause severe complications, including:
- Creating a hold in the heart,
- Internal bleeding,
- Tearing veins and arteries leading to and from the heart, and
- Heart attack.
These problems often require immediate action, including open heart surgery, to correct.
Additionally, when an IVC filter migrates, the risks of a pulmonary embolism return because the filter is no longer in place to catch a blood clot traveling up the inferior vena cava. This risk is especially important because a migrating IVC filter, itself, does not present noticeable symptoms – patients and doctors rarely notice that an IVC filter has migrated somewhere until it has caused problems in its new location. In the meantime, the risk of a potentially fatal pulmonary embolism has returned.
3. Symptoms that an IVC filter has migrated
When an IVC filter breaks or dislodges and migrates, most patients do not feel anything. It is only after the IVC filter has traveled and caused other problems to the inferior vena cava vein or to other organs that symptoms begin to appear.
These symptoms include:
- General back pain,
- Pain in the chest or abdomen,
- Neck pain,
- Low blood pressure,
- Confusion, and
- Arrhythmia or other problems with the heart's rhythm.
Because these symptoms are not specific or apparently related to the IVC filter, and because they often only happen more than a month after the filter was implanted, many patients and even some doctors fail to recognize the signs that the filter has migrated.
U.S. Food and Drug Administration, “Removing Retrievable Inferior Vena Cava Filters: FDA Safety Communication” (May 6, 2014).
Morales JP, et al., “Decision analysis of retrievable inferior vena cava filters in patients without pulmonary embolism,” Journal of Vascular Surgery 1(4):376-84 (October 2013).
U.S. Food and Drug Administration, “Removing Retrievable Inferior Vena Cava Filters: Initial Communication” (Aug. 9, 2010).
Angel LF, Tapson V, Galgon RE, Restrepo MI, Kaufman J, “Systematic review of the use of retrievable inferior vena cava filters,” Journal of Vascular and Interventional Radiology 22(11):1522-30 (November 2011).