IVC Filter: a Stationary Object in a Continually Moving Body – Could Designers Not Have Foreseen this Problem?
One fact about the bodies of virtually all animals – including those of homo sapiens – is that Nature designed them to be in continual motion, even when appearing dormant. Even when sleeping or at rest, bodies stir, twitch and roll over.
During most of its waking hours, the human body is walking, running, manipulating objects using arms and hands, bending over, standing, sitting, and more (at least it should be). Given this, why would the designers of the inferior vena cava (IVC) filter create a device intended to remain in one place?
The fact is that it does not. Migration is one of the most serious problems with the IVC filter. This occurs when it either breaks or falls out of place altogether, and the pieces travel through the circulatory system, causing serious injuries when they lodge in organ tissue. This was the case for a Pennsylvania man who recently filed a lawsuit against C.R. Bard, alleging that his injuries resulted from the implantation of a G2 IVC Filter in 2008.
That model was introduced only three years earlier as a replacement for the previous device, the Recovery IVC Filter. The old model had been on the market for only three years before it was found to have serious defects, which included tilting, migration and fracturing.
Significantly, the G2 had only been out for four months before an executive at Bard wrote an internal memo expressing his own worries about the same problems with the “new” model. Eventually, reporters for NBC News discovered that C.R. Bard was aware of the dangers of its product, yet continued to produce the G2 and G2 Express until 2010 – by which time over 160,000 units had been sold.
One appalling aspect of this is that many of these devices have been used for spinal trauma patients, the majority of whom are young men – who tend to be more physically active. Dr. Ravi Kapadia of the Albert Einstein College of Medicine recently studied the effectiveness of IVC filters as a way to prevent thrombosis in spinal cord patients. His findings revealed that such patients were more likely to suffer blood clots than those who took anticoagulant medications. In a recent article appearing in General Surgery News, Kapadia said,
“Since a filter predisposes to thrombogenesis [formation of blood clots], we really need to consider the consequences for the patient, such as the likelihood that we’ll be able to retrieve the filter and the age of the patient. Most of our trauma population [is composed of] young adult males. It’s one thing to have a filter as a 70-year-old, but it’s another thing when a 20-year-old is walking around with one.”
The IVC filter was a great idea in theory – simply create a sieve to catch blood clots before they can reach the heart and/or lungs and cause serious injury or death. However, it turns out that in practice, the device is ill-suited by its very design to serve the function for which it was designed.