Blood clots are a common—and potentially fatal—condition associated with significant trauma and a variety of surgeries and medical treatments. Typically forming in the legs, clots have the ability to travel to your lungs, plugging vital vessels in those organs and resulting in a pulmonary embolism. One-third of people with untreated pulmonary embolisms do not survive.

Doctors have long prescribed blood-thinners (such as Coumadin or Warfarin) to combat the development of blood clots, but some patients cannot tolerate these medications. In the 1970s, in response to this need, medical engineers developed the first “IVC filter” to implant into patients at risk for blood clotting who could not take blood thinners.

The inferior vena cava is shown as the large blue vein travelling from the legs, between the kidneys, directly to the heart.

The inferior vena cava is shown as the large blue vein travelling from the legs, between the kidneys, directly to the heart.

“IVC” is an acronym for the inferior vena cava, the largest vein in the body. With an average diameter of 2 centimeters, the function of the inferior vena cava is to drain all of the deoxygenated blood from the lower body into the heart, at which point the blood is pumped to the lungs for a new dose of oxygen. The “IVC filter” is a metallic, net-like device inserted into the inferior vena cava through the femoral vein. The metal prongs of the filter are designed to stop significant clots in the IVC, thereby preventing their migration to the lungs.

IVC filters first appeared on the market in the 1970s. Boston Scientific designed and marketed the first model, known as the “Kimray-Greenfield filter” (or KG filter), and it enjoyed substantial success. The KG filter was designed to be permanent and required annual check-ups for evidence of clotting around the filter, evidence of damage to the blood vessel, or signs that the filter was migrating towards the heart.

In 1995, a prospective study revealed that KG filter recipients were experiencing recurrent pulmonary embolisms in only 4% of cases, that damage to the inferior vena cava was negligible, and that only 8% of patients showed any movement of the filter within the IVC itself.

An example of one model of IVC filter. The tip of the filter is inserted through the femoral vein towards the heart. Upon releasing the filter, the “legs” expand to the internal wall of the inferior vena cava.

An example of one model of IVC filter. The tip of the filter is inserted through the femoral vein towards the heart. Upon releasing the filter, the “legs” expand to the internal wall of the inferior vena cava.

The success of the KG filter caught the attention of Boston Scientific’s competitors and the race to patent better filters for more prolific uses was on. The biggest problem the industry faced, however, was the fact that pulmonary embolism patients who cannot use blood thinners are relatively few in number. So even if KG filter competitors gained market share, the market itself was quite small.

The competitors—primarily Bard, Cook Medical, and Cordis—chose to attempt to expand the market and differentiate their products from the KG filter by creating a line of filters that could be removed from the inferior vena cava after a short period of time. Theoretically, such filters could then be prescribed for patients for whom the permanent KG filter would not be—namely, those for whom a pulmonary embolism was not an existing problem, but was merely a threat due to tangential (and very common) medical issues such as traumatic injuries, cancer treatment, orthopedic surgery, OB/GYN surgery, and bariatric surgery.

The first “retrievable filters” began to be implanted in late 2003. The marketing efforts of Bard, Cook, and Cordis dramatically increased the ubiquity of the product: in 2004, 49,000 filters were implanted; by 2013, approximately 400,000 Cook filters, alone, were implanted (and Cook controlled only 43% of the market).

But trouble was on the horizon. The “retrievable” filters turned out to be not-so-retrievable. Within weeks of the filters’ insertion, the walls of the inferior vena cava began to grow around the metal “legs” of the filter. This increased the danger of removal of the filters, as doing so risked puncturing the largest vein in the body—a possibly fatal consequence for the patient.

As more doctors abandoned the practice of retrieving these devices, additional problems began to arise. The filter “legs” began to punch through and protrude from the walls of the inferior vena cava. The device would sometimes tilt, placing unequal pressure on the legs. Those that did not punch through the vein often broke off, becoming free-floating objects and lodging themselves in the patient’s heart or lungs. Worst of all, the device broke free of the vein of some patients, becoming lodged in the heart and requiring open heart surgery.

This is an image of open heart surgery being performed on a patient whose IVC filter has migrated through the inferior vena cava approximately 10 inches from its place of implantation (about an inch below the kidneys) into the heart itself. The white arrow indicates the filter, which is covered in tissue.

This is an image of open heart surgery being performed on a patient whose IVC filter has migrated through the inferior vena cava approximately 10 inches from its place of implantation (about an inch below the kidneys) into the heart itself. The white arrow indicates the filter, which is covered in tissue.

As one might imagine, a flood of litigation has ensued. Presently, 1,244 lawsuits are pending against Bard in federal court. These suits have been consolidated, for discovery purposes only, in the District of Arizona. Likewise, 1,237 suits are pending against Cook, consolidated in the Southern District of Indiana. The first Cook case is scheduled to be tried on October 2, 2017 while no trials of Bard have been scheduled as of yet.

Our law firm is investigating many IVC filter cases across the State of South Carolina. If you would like to speak to a Columbia personal injury lawyer at Chappell, Smith & Arden about your potential case, please call us at 1 (800) 531-9780 or contact us online.