IVC Filters

Blood clots (emboli) that form in the deep veins of the leg occasionally break free and travel through the pulmonary artery into the heart or lungs, causing life-threatening complications. This risk is most prevalent in patients with deep vein thrombosis (DVT) who are generally treated with anticoagulant therapy. For those who cannot tolerate anticoagulant drugs, or who do not respond well to blood thinning agents, an IVC filter is the next option.

IVC filters are designed to catch clot fragments as they move through the vena cava. This prevents them from reaching the lungs and heart, where they have the potential to cause chest pain, difficulty breathing, pulmonary embolism (PE) and even death. Pulmonary emboli are responsible for more than 300,000 deaths every year in the United States, and even when caught early, can still cause permanent damage to lung tissue.

IVC filters are cone-shaped devices implanted in the inferior vena cava. They function by letting blood flow around the clot. Over a period of days and weeks, the body’s own anticoagulants begin to break the blood clot down.

Introduced in 1979, inferior vena cava filters used to be permanent devices, but newer generations of the filters are “optionally retrievable,” allowing surgeons to remove them at a later date after the risk of pulmonary embolism has passed. While retrievable IVC filters can provide effective, short-term protection from the dangers of pulmonary embolism, they have been connected to a number of severe complications, including filter migration, fractures, and the perforation of organs and blood vessels.

These grave problems have been the topic of intensifying litigation against IVC manufacturers such as Cook Medical and C.R. Bard.

Candidates for IVC filters

An IVC filter may be recommended for patients who:

• Have large blood clots in the iliac veins or inferior vena cava
• Experience serious bleeding complications from blood thinning medications
• Have been diagnosed with DVT and are slated for major surgery
• Continue to suffer from deep vein thrombosis or pulmonary emboli despite therapy with anticoagulants
• Cannot tolerate traditional blood thinning agents for health reasons
• Need life-saving measures after severe trauma

Implantation of vena cava filters

The implantation of an IVC filter is an endovascular procedure, where surgeons generally use the jugular or femoral vein. The patient is first injected with contrast dyes which can be tracked by X-ray images as the dye circulates through the bloodstream. With this visual imaging guidance, surgeons then insert a catheter to the filter placement site. The filter is then guided through the catheter’s hollow tube until it reaches the precise location within the artery. The entire procedure takes less than one hour and is performed under local anesthetic.

IVC filter risks during and shortly after the procedure may include:

• Allergic reaction to contrast dyes
• Excessive bleeding
• Potential injury to blood vessels
• Bruising and bleeding at the insertion site
• Infection
• Filter misplacement

Serious risks associated with IVC filters

Though less common, there is a possibility that the IVC filter can change position, lodge in the wrong part of the vessel, or puncture a vein. In fact, over the last 15 years, the FDA has received more than 920 adverse event reports regarding IVC filters, some of which led to substantial injury to patients.

Detachment of filter components, IVC perforation, filter fracture and device migration were reported in a 2010 safety communication issued by federal health regulators. The FDA cautions that such complications may be caused by leaving a retrievable filter in the body for too long, and in 2014 stated that the “risk/benefit profile begins to favor removal of the IVC filter between 29 and 54 days after implantation.”

A study in the Archives of Internal Medicine suggests that the Bard Recovery and G2 filter may be more prone to failure, giving credence to recent claims made in lawsuits filed against the company. Other research published in JAMA Internal Medicine in 2010 concluded that the “Recovery and Bard G2 filters had high prevalences of fracture and embolization, with potentially life-threatening sequelae.”

In a recent IVC filter lawsuit, plaintiff Clifford Geter alleges that after having the Bard G2 IVC filter implanted in 2008, the device tilted, penetrating his inferior vena cava wall. Like others who have suffered adverse outcomes with a medical device that was intended to prevent injury, Geter contends that Bard manufactured and sold an unreasonably dangerous device and failed to adequately warn about inherent risks.

Other claimants have needed open heart surgery to remove splintered filter struts that came loose after implantation.

Bard isn’t the only manufacturer facing litigation regarding IVC filter complications; Cook Medical is defending claims that its Celect and Gunther Tulip devices are defective and dangerous. According to allegations, the vena cava filters have a tendency to fracture, allowing small pieces to break off and perforate vessel walls, leading to long-term organ damage.

For some patients, once the filter has migrated or fractured, it becomes almost impossible to surgically remove in its entirety due to risk of long-term complications.

Ongoing study on safety of IVC filters

Some of the most predominant manufacturers of inferior vena cava filters in the United States include:

• Cook Incorporated
• R. Bard
• Cordis Corporation
• ALN Implants Chirurgicaux
• Argon Medical Devices
• B Braun Interventional Systems
• Rex Medical
• Volcano Corporation

Some of the these companies are involved in the PRESERVE (Predicting the Safety and Effectiveness of InferioR VEna Cava Filters) study, a national effort that will enable medical professionals to better evaluate the safety profile of both retrievable and permanent IVC filters, and hopefully improve patient care.

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