Background: Inferior vena cava (IVC) filters are effective in preventing pulmonary embolism in patients at risk. This study aimed to investigate whether the dwell time of retrievable IVC filters have impact on IVC lumen diameter.
Methods: The clinical data of 36 patients treated with retrievable IVC filters from January 2016 to November 2018 were retrospectively collected. A total of 33 filters were successfully removed. At times of filter placement and removal, the IVC lumen diameter (at upper, middle, and lower levels of the filter), distance between the filter upper end and the right renal vein opening, and degree of filter tilt were measured.
Results: IVC filters were placed because of deep vein thrombosis in the lower limbs after fractures in 26 patients. The median dwell time of the IVC filters was 18 days. From the time of filter placement to that of removal, the IVC diameter decreased significantly at the middle (28.07 ± 5.92 vs. 25.73 ± 7.33 mm, P = 0.002) and lower levels (27.48 ± 4.73 vs. 26.36 ± 4.72 mm, P = 0.003) of the filters. No significant difference was noticed in the IVC diameter at the upper levels of the filters (27.78 ± 6.43 vs. 27.11 ± 6.63 mm, P = 0.082). Positive correlation was noticed between filter dwell time and IVC diameter changes at the upper (r = 0.381, P = 0.029) and middle (r = 0.555, P = 0.001) levels of the filters. No significant change was noticed in the distance from the filter upper end to the right renal vein opening and the degree of filter tilt.
Conclusions: Retrievable IVC filters are associated with IVC stenosis. The severity of IVC stenosis is positively correlated with the dwell time of filters.
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