IVC filters may migrate or break over time
The inferior vena cava is a dynamic structure that expands and contracts with each heartbeat. While most IVC filters have superb design and engineering, the cumulative stress on the metal components of a filter over years of dwell time can cause components to break, rendering the filter less effective or causing it to migrate. IVC filters that migrate to the heart can result in significant health risks including arrhythmia and need for open cardiac surgery. From 2005 to 2014, nearly one thousand IVC filter complications were reported to the FDA. Of these, 328 involved device migration, 146 involved embolizations (detachment of device components), and 56 involved filter fracture. While this number of reported complications is significant, it is likely that the extent of IVC filter-related problems greatly exceeds those reported to the FDA. This led to the FDA to release a recommendation in 2010 that reads: “The FDA recommends that implanting physicians and clinicians responsible for the ongoing care of patients with retrievable IVC filters consider removing the filter as soon as protection from PE is no longer needed.” The full FDA safety communication statement can be viewed http://www.fda.gov/MedicalDevices/Safety/AlertsandNotices/ucm221676.htm.
IVC Filter Components May Penetrate the IVC and Cause Symptoms
IVC filters are designed with radial force, meaning the struts of the filter place an outward force on the wall of the inferior vena cava. Radial force is one important aspect ofif IVC filter design that allows the collapsed IVC filter to open and adhere to the IVC wall after deployment from a vascular sheath. Radial force is necessary to minimize filter migration and allows deployment from relatively small vascular sheaths, but carries an important downside. The constant outward force on the IVC can result in perforation of the filter strut beyond the wall of the IVC. This is a very common phenomenon, occurring on 79% of patients in one study[AB1] . Although strut perforation is common, in some patients the IVC filter strut may touch or enter an adjacent structure such as the aorta, small intestines, or spine. A perforated IVC filter strut has potential to damage or irritate any of these adjacent structures and cause pain.
For more information regarding strut perforation, please view an article published in the Journal of Vascular and Interventional Radiology: http://www.jvir.org/article/S1051-0443(15)00594-1/pdf.
IVC Filters May Cause Formation of Additional Blood Clots
Although IVC filters are designed to mitigate the negative impact of blood clot formation, there is emerging evidence that indwelling IVC filters are associated with very high rates of deep venous thrombosis. The exact mechanism by which this happens is not totally clear, however there are two likely factors that contribute: 1) An indwelling IVC filter creates turbulent blood flow in the IVC and 2) the body’s reaction to an IVC filter results in narrowing of the IVC in and around the filter. It is likely that one or both of the factors lead to more stagnant blood return from the legs, increasing the likelihood of deep venous thrombosis. This occurs in an estimated 13% of patients (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4736520/).
Long term, large-burden of DVT predisposes patients for post thrombotic syndrome (PTS), a debilitating disease where circulation to and form the legs is reduced. PTS is associated with chronic leg pain, skin ulcerations, and in extreme cases may contribute to gangrene.
Figure 3 – An example of a patient with leg ulcers related to post thrombotic syndrome
[AB1]http://www.ncbi.nlm.nih.gov/pubmed/26233837
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