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WASHINGTON -- The same year that the FDA warned against long-term use of inferior vena cava (IVC) filters, placement rates took a downward turn, researchers said.

Separately, one center reported success with systematic IVC device retrieval.

It is likely that the that warned against long-term use of IVC filters had something to do with the devices' decreasing popularity, according to two studies presented here at the Society of Interventional Radiology meeting.

The first, a retrospective analysis of IVC filters placed 1993-2014 from a 20% stratified sample from the National Inpatient Sample (NIS), found that before the FDA safety alert, IVC filter placements were rising 9.36% annually; afterward, rates fell an average of 7.36% per year.

And it wasn't because deep vein thrombosis and pulmonary embolism were less common -- rates of those remained fairly constant, suggested , a resident at Chicago's Rush University Medical Center.

Moreover, Petal reported that the "greatest decline in utilization occurred in the Northeast, an area with a more litigious medicolegal environment." Other geographical trends of note: conservative use of IVC filters in the West throughout the study period contrasting with rampant usage in the South. Petal had no explanations for these patterns.

The second study also suggested that 2010 was the turning point, via a different analysis of NIS data.

a resident at University of Arkansas for Medical Sciences at Little Rock, also noted a geographical discrepancy regarding IVC filter placement, reporting that while IVC filters generally dropped off after the 2010 FDA advisory, the South still places twice as many as the West.

In the single-center study, from Northwestern Medicine in Chicago, a dedicated IVC filter retrieval program, has continued to see booming business.

Patients there are followed by a dedicated nurse coordinator who contacts the referring clinician after IVC filter placement to set up device removal 2-3 weeks later, according to resident .

An updated look at traffic before and after the program was established in 2009 showed that retrievals shot up from 34.2% to 69.6% (P<0.0001) with year-by-year increases in these retrievals.

"Systematic follow-up of patients with IVC filters improves retrieval rates," Andreoli concluded.

Still, retrieval was not without risks. There was a 3.9% complication rate associated with the procedure, the bulk of complications being access site problems (n=20) and IVC extravasations (n=13).

Moreover, one member of the audience noticed that IVC placements seemed to be rising at Andreoli's center.

"Our absolute number is going up because we are taking from others. Cardiovascular surgeons doing these [IVC filter placements] have dwindled," explained , also of Northwestern. "We haven't been placing for more indications, we've been placing more than other people in the hospital."

"It's not an enviable position to have," he said.