A team of doctors from the Children’s Hospital of Philadelphia, Perelman School of Medicine of the University of Pennsylvania, recently published a study in Pediatric Radiology on the challenges of removing inferior vena cava (IVC) filters in children. These filters are implanted to prevent blood clots from being carried into the heart and lungs.
Research studies have indicated increases in the rate of venous thromboembolismâ€”the obstruction of a blood vessel by a blood clot dislodged from elsewhereâ€”in children. An IVC filter is one of the treatments used to keep clots from reaching the heart and lungs, but doctors have concerns about the use of IVC filters in children.
IVC filters are typically used when the individual at risk for clots cannot take anticoagulant drugs or when anticoagulant drugs do not work well enough or fast enough, according to the Mayo Clinic. But complications can arise with long-term IVC filter implantation, including filter migration from the original site, clotting within the filter, and parts of the filter breaking off, which can lead to severe pain, bleeding, further clots, and other life-threatening complications. Broken-off parts of an IVC filter can penetrate the inferior vena cava, the aorta and the duodenum. For children, there is the additional concern that long-term filter placement in a child can negatively affect the growth of the childâ€™s inferior vena cava.
C.R. Bard, the major manufacturer of IVC filters faces numerous lawsuits over deaths and injuries associated with IVC filters.
The Philadelphia researchers studied IVC filter removal in pediatric patients and they noted two major causes of retrieval failure â€” tip embedding and tilt, which are likely to worsen the longer the filter remains in place. Prolonged embedding may lead to tissue formation around the filter hook within the wall of the inferior vena cava, and this may make retrieval difficult or imprudent. With prolonged implantation time, the child may experience acute abdominal and leg pain.
The researchers performed a retrospective 10-year review of 20 children who underwent IVC filter retrieval. The subjects were 13 males and 7 females, ranging in age from 12-19Â years. The mean implantation time for the IVC filter was 63Â days, with a range of 20 to 270Â days. Standard retrieval was performed in 17 of the 20 patients (85%). Additional (adjunctive) techniques were required for 3 patients (15%) and included the double-snare technique, balloon assistance, and endobronchial forceps retrieval. Median procedure time was 60Â minutes (range: 45-240Â min). Pre-retrieval cavogram demonstrated filter tilt in 5/20 patients (25%) with a mean angle of 17Â° (range: 8-40). Pre-retrieval CT demonstrated strut wall penetration and tip embedment in one patient each. There were two procedure-related complications: IVC mural dissection noted on venography in one patient and snare catheter fracture requiring retrieval in one patient. The authors say there were no early or late complications.
In their conclusion, the researchers said, â€śIVC filter retrieval can be performed safely but may be challenging, especially in cases of filter tilt or embedding.â€ť Doctors may need to employ adjunctive techniques to safely remove the filters.