Research studies have reported increases in the rate of venous thromboembolism (obstruction of a blood vessel by a blood clot dislodged from elsewhere) in children and doctors have implanted inferior vena cava (IVC) filters to prevent clots from being carried into the heart and lungs.
Doctors at the Children’s Hospital of Philadelphia, Perelman School of Medicine of the University of Pennsylvania, have just published a study in Pediatric Radiology on the removal of IVC filters in children, PubMed reports.
IVC filters are typically used for people who cannot take anticoagulant drugs or when anticoagulant drugs do not work well enough or fast enough, according to the Mayo Clinic. Long-term filters have been associated with complications including filter migration, clotting within the filter, and breakage of parts of the filter, 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. Researchers have speculated that long-term filter placement in a child can negatively affect the growth of the child’s inferior vena cava.
Device maker C.R. Bard faces numerous lawsuits resulting from injuries and deaths associated with its IVC filters.
In their study, the Philadelphia research team noted two major causes of retrieval failure — tip embedding and tilt, which are likely to worsen the longer the implantation period. Prolonged embedding may lead to tissue formation around the filter hook within the wall of the inferior vena cava, making 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 (13 male, 7 female), ranging in age from 12-19 years, who underwent IVC filter retrieval. The mean implantation period for the IVC filter was 63 days, with a range of 20 to 270 days. Standard retrieval was performed in 17 of the 20 patients (85%). Adjunctive techniques were performed in 3 of 20 patients (15%) and included the double-snare technique, balloon assistance, and endobronchial forceps retrieval. Median procedure time was 60 minutes (range: 45-240 min). Pre-retrieval cavogram demonstrated filter tilt in 5/20 patients (25%) with a mean angle of 17° (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. There were no early or late complications.
The researchers concluded that “IVC filter retrieval can be performed safely but may be challenging, especially in cases of filter tilt or embedding.” Doctors may need adjunctive (additional) techniques to increase filter retrieval rates.