Study: Cook IVC Filter May Not Do You Any Good, and May Cause Harm

People who get medical implants don’t do so out of boredom. They get the surgery because they have a serious medical problem or they want to prevent one. Many of these implants have benefits for patients while some, in addition to doing some good, also can do great harm. The Cook IVC filter may be a medical implant that not only may do you no good but can also do great harm, according to a recent study published in the medical journal Annals of Surgery.

What is a Cook IVC filter?

The Cook IVC filter is a wire device that looks like a cone shaped net. It is manufactured by Cook Group, Inc. The IVC filters are surgically inserted into a major vein, the inferior vena cava (IVC), of a patient who is at risk for a pulmonary embolism (or PE, a blood clot that passes into a lung, which can be fatal). The filter is supposed to trap or break up blood clots coming from the lower or middle part of the body. On first look it appears to be a great idea. But many medical emergencies have resulted from implantation of these IVC filters.

Hundreds of lawsuits have been filed by those injured by Cook IVC filters and by the families of people who died because of them. The filters are often in patients too long; they can break up (with pieces going into the heart or lungs) or the entire filter can be pushed up near or into the heart, causing death or injuries.

Study finds no upside to using IVC filters but does find a down side

Often physicians will use a Cook IVC filter after a patient has suffered an accident or some kind of trauma fearing a blood clot may form and move into the heart or lungs. Researchers did the study to see if they could establish a benefit for trauma patients treated with implantation of IVC filters.

After looking at the records of 803 patients from 2010 to 2014 who had an IVC filter implanted in them after a traumatic event, those conducting the study not only found no benefit but also an increased risk of injury. The survival rates of patients with IVC filters implanted to prevent potential injuries were no better than those without them. In addition to this lack of benefit they found use of the filters resulted in an increased chance of getting deep vein thrombosis.

• Deep vein thrombosis (DVT) is the term for when a blood clot forms in a vein deep in the body.
• This condition occurs in the lower leg or thigh most often but may occur in other parts of the body as well.
• One of the dangers of DVT is that the clot may break off and move through the bloodstream possibly ending up in the heart or lungs.

The purpose of the study was to see if IVC filters prevented health problems, so those already diagnosed with DVT or PE were not made part of the study. Further, the use of the filters varied widely depending on which hospital treated the patient. In some areas the local doctors inserted them at a much higher rate than others.

What the study means for doctors, patients, and lawsuits

Use of any kind of medical implant involves weighing the costs and benefits for the patient. Given this study,

• There was no benefit for those who were injured in an accident to use an IVC filter to prevent possible future blood clots from moving into the heart or lungs. That is to say, there was no evidence that the patient will live a shorter life without one, but
• There are risks (an increased risk of DVT along with the dangers posed by a defective filter breaking up and causing harm).

In legal proceedings this kind of information may also be helpful to show those involved in the manufacture and sale of Cook IVC filters (and other IVC filters) may have acted negligently and should pay damages to those harmed by the device. Without any measurable benefit to the patient, exposing that patient to a known risk would be evidence of negligence.