Migration of an Inferior Vena Cava Filter
By now, you’ve heard about the IVC filter, a spider-like device, and its link to a variety of complications and even deaths in the patients who’ve received the implant.
For patients who cannot take anticoagulants or blood thinners, an IVC (Inferior Vena Cava) filter is thought to be the ideal way to trap blood clots so they do not reach a patient’s heart or lungs, where they could have fatal results such as a heart attack or pulmonary embolism.
A number of studies have outlined the problems with IVC filters namely – filter migration, embolization and fracture. The same pattern of defective design has been noted in numerous studies.
About one-and-a-half inches, the delicate filter is made of nitinol, a mixture of nickel and titanium. The spindly legs are prone to break off and migrate inside the body.
That’s what happened to Dodi Froehlich. The mother of two was in a high impact auto collision. As a result she had a high risk of blood clots traveling up her body. So she was fitted with the Recovery IVC filter made by C.R. Bard. Four months later, NBC News reports she went to the emergency room with headaches and passed out. She flat lined in the hospital and a priest was called.
The Bard filter had broken off and pierced her heart. No one expected her to survive, but Froehlich pulled through. She was one of the lucky ones.
The IVC filter is placed dangerously close to the heart and lungs in the largest vein in the body, the inferior vena cava. When migration or fracturing occurs, those organs can be pierced. Fluid buildup in the space around the heart has been noted which interferes with heart function.
The device may also erode in the body.
There have been more than 900 reports of complications and nearly 30 deaths reported to the U.S. Food and Drug Administration (FDA) concerning IVC filters. Those made by C.R. Bard have stood out as among the worst.
Since the Bard G2 device was introduced in 2005, the adverse event reports submitted to the FDA include 328 reports of device migration; 146 reports of detachment of the device components also known as embolization; 70 reports of the IVC perforating nearby organs and 56 IVC filter fractures.
Migration is defined by researchers at Johns Hopkins as movement of more than 10 mm and is seen in as many as 10 percent of all patients reviewed in 1997.
A study in the Journal of Invasive Cardiology in November 2009, reported on the case of a vena cava filter migration that happened to one patient brought to their hospital in Royal Oak, Michigan. The filter was found to be in the right ventricle. It had to be removed surgically by using cardiopulmonary bypass.
When looking at this case as well as 27 other reported cases of filter migration, it was noted the newer filters made of nitinol (nickel and titanium), phynox and elgioly (both cobalt-chromium alloys) have a higher risk of filter migration into the right ventricle when compared to the older model of Greenfield IVC filter, which is titanium-based.
The researchers note the newer retrievable filters have more of a problem with migration with that problem increasing over the past ten years. As a result there have been more reports of surgical removal, deaths and serious ventricular arrhythmias.
IVC filter migration might also encompass reports of tilting of the vertical device 15 degrees from the midline. That is considered to then be on its side and less likely to do the job it was placed to do of capturing blood clots.
Even the FDA in 2010 issued a warning after receiving 921 reports of complications involving IVC filters. The most frequently seen complication was migrating, noted in 35 percent of adverse events. Detaching device components (146) and perforation of IVC (70) and 56 instances of filter fracture were all noted by the FDA.
Thinking about IVC filters has evolved over time. It was originally assumed they could be left in indefinitely. The FDA now recommends removing a retrievable IVC between 29 and 54 days after it is implanted, or after the danger of a pulmonary embolism has subsided.
Bard with its Recovery and G2 are not the only IVC filters with problems of migration. Cook Medical’s Gunther Tulip and the Celtic were shown to present a 43 percent risk of perforating or migrating into a patient’s vena cava wall. That most frequently occurred within 71 days after being implanted. Migration of the IVC filter was a problem in about 40 percent of patients. That study appeared in the July 2015 Journal of Vascular Interventional Radiology.
That has Cook Medical facing more than 100 lawsuits consolidated in multidistrict litigation in federal court of the Southern District of Indiana.
Researchers at the University of Rochester Medical Center raise the question whether the use of IVC filters is doing anything to increase the long-term survival benefits over other treatments.
Adding to the complication, the majority of prophylactic IVC filters are not removed and may actually be causing more harm in the long run.