Placing a New Filter before Removing Embolized Nonconical Filter: A Report of 13 Cases.

Objectives: Permanent filter placement may result in numerous complications. Filter removal is recommended if there are no risks of pulmonary embolism. This study aimed to explore the feasibility of placing a new filter when the embolized nonconical filter is removed.

Methods: This study included patients who had received a new filter between 2018 and 2019 before the nonconical filters were removed. Patient characteristics, new filter types, thrombus interception rate, filter removal rate, feasibility, and safety were analyzed retrospectively. Feasibility was defined as the successful placement of new filters and the removal of the nonconical filters. Safety was defined as the absence of symptomatic pulmonary embolism and inferior vena cava hemorrhage after removing the nonconical filters, as well as the successful removal of new filters without symptomatic pulmonary embolism.

Results: The average indwelling period of the nonconical filters was 29 (range, 17-30) days among the 13 patients. The removal rate of the nonconical filters was 100%. Five patients (38.5%) received new Denali filters, one (7.7%) received a new Celect filter, and 7 (53.8%) received new temporary filters. Thrombi were intercepted in 10 of the patients (76.9%). The removal rate of the replaced new filters was 100%. No rupture or shifting of the new filters occurred. No symptomatic pulmonary embolism was found after the removal of both the nonconical filters and the new filters. The patients were followed up for 3 months after the surgeries, and the inferior vena cavae of 12 (92.3%) patients were patent, and no new embolic events were found.

Conclusions: Placing a new replacement filter before removal of the embolized nonconical filter may be a feasible approach to prevent pulmonary embolism. Both the nonconical filter and the new filter could be removed subsequently after the thrombi were treated.