The Inferior Vena Cava Filter Placement Parameters May Predict Filter Retrieval Outcomes

Background: We aimed to investigate the potential correlation between the placement factors of various retrievable inferior vena cava filters and retrieval outcomes. Additionally, we aimed to identify the factors affecting the placement tilt of the filter. Methods: This retrospective study was conducted at a tertiary care center to investigate patients who had previously undergone retrievable filter placement at our center and who subsequently had their filters removed between January 2020 and December 2021. Patient characteristics and filter-related factors were recorded. Complex filter retrieval was defined as cases that required a minimum of 8 minutes of fluoroscopy or that involved advanced techniques. Regression models were used to explore patient- and placement procedure-related factors that could influence retrieval outcomes and the placement tilt angle. Results: The study included 163 patients, and all filters were successfully retrieved. Thirtyseven (22.7%) retrievals were classified as complex retrievals. The mean diameter of the inferior vena cava in the preplacement position for the entire cohort was 16 +/- 1.8 mm. The median filter tilt angles at placement and retrieval were 5.0 degrees (IQR, 1.8 degrees-9 degrees) and 4.6 degrees (IQR, 2.1 degrees-8.0 degrees), respectively. The placement tilt angle was not significantly associated with complex retrieval (P - 0.59). The filter hook abutment to the vena cava wall (OR, 10.76, P - 0.003), dwell time (OR, 1.02, P - 0.029), and diameter of the vena cava (OR, 10.21, P < 0.001) were associated with complex retrieval. The diameter (P - 0.049), age (P - 0.049), and filter brand (P - 0.001) were found to be significantly associated with placement tilt. Conclusions: The inferior vena cava diameter at the time of placement predicts difficulty in filter retrieval. In addition, the filter hook abutting the inferior vena cava wall and long indwelling time may complicate retrieval. The vena cava diameter is also closely related to the degree of filter tilt.