IVC filters stir controversy despite being implanted in millions of people in the last 30 years or so. Increasingly, learned professionals in the medical community question the safety and efficacy of IVC blood clot filters. As IVC filter lawsuits are being continuously filed across the country, more and more people seem to be paying attention to the IVC Filter Controversy.
IVC Filter Safety Concerns
“Indications for prophylactic placement of an IVC filter are controversial.” – Mark R. Hemmila, MD (2015, Annals of Surgery, a monthly review of surgical science since 1885).
“Use of Vena Cava Filters during bariatric surgery showed Higher Mortality than no Filter.” – Nancy Birkmeyer, PhD (Annals of Surgery).
“How could a medical device be so well accepted without any evidence of efficacy?” – Vinay Prasad, MD; Jason Rho MD; Adam Cifu, MD (2013, JAMA).
IVC Filter Indications
The only people for whom IVC filter installation is approved or indicated are those for whom anti-coagulation therapy (blood thinners) are contraindicated. IVC filters are frequently put into people after car accidents or other incidents involving emergency medical intervention or trauma. The main justification is that the filters have been believed to help prevent pulmonary embolism (PE), a potentially lethal complication. However, research indicates that IVC filters often fail to prevent PE; in point of fact, they may even increase the risks of a patient’s developing PE.
No Survival Benefit for Trauma Patients
An American Surgical Association presentation April 2015 by seven doctors concluded that prophylactic Inverior Vena Cava (IVC) filter placement resulted in no survival benefit for trauma patients. See it here: ASA Meeting: April 23-25, 2015.
Conclusions of Mark R. Hemmila, MD; Nicholas H. Osborne, MD; Peter K. Henke, MD and others included:
* the incidence of prophylactic IVC placement (trauma, bariatric surgery) is increasing at a significantly higher rate than placement after a VTE (DVT or PE) event (157% vs. 42%) from 1998- 2005.
* The incidence of PE during same time/frame has increased more than two-fold based upon data from the National Trauma Data Bank (NTDB).
No Clinical Trial shows IVC Filter Safety or Efficacy
The most troubling fact about IVC filters is that no clinical trial – the gold standard for medical device safety and efficacy – has ever shown that these products are safe and effective, for any indication. Most, if not all, medical devices approved through the FDA’s non-rigorous 510(k) process have some clear predicate device which a manufacturer uses to grease the skids for subsequent device approval. Inexplicably, IVC filters seem to follow no clear predicate device that had been put through rigorous safety and efficacy testing.
IVC Filter HistoryThe first IVC filter to hit the market was the Mobin-Uddin umbrella filter in 1967, a percutaneous device to intercept a blood clot using an umbrella filter. It was associated with high rates of IVC occlusions (clogged or obstructed), PE, and migration.
In 1973, a vascular surgeon named Dr. Lazar Greenfield introduced a conical permanent IVC filter, which became known as the Greenfield Filter. That verdant name became something of a generic term for many subsequent copycat filters which were not in fact “Greenfield filters.” This Greenfield filter, made of stainless steel, was the first long-term filter, and it served as the basic design upon which modern conical filters are based.
Automobile vs. Human Body
The Greenfield filter was a result of collaboration with petroleum engineer Garman Kimmell, who thought his work in cars could relate to human bodies. Mr. Kimmell drew a parallel between the problems of pulmonary embolism in human beings and sludge buildup in oil extraction. The latter was addressed with a cone-shaped filter that would funnel sludge toward center while allowing oil to flow around it. (One was an inanimate object, the other a soft-tissue sentient being with lungs and a heart; but let’s not get bogged down in minor details.)
To be continued. . .