618 - Volumetric CT Analysis of Inferior Vena Cava Filters Predicts Long-Term Complication Risk

Purpose: Inferior vena cava (IVC) filters are widely used to prevent pulmonary embolism in patients with contraindications to anticoagulation. However, prolonged dwell times are associated with complications such as penetration and fracture. This study aimed to analyze temporal changes in IVC anatomy and filter orientation using serial volumetric CT analysis to identify imaging predictors of long-term complications.

Materials and Methods: This retrospective study (2010-2024) included 31 patients (mean age 60.1 years; 61.3% male) with IVC filters in place for ≥3 years. Scans were analyzed at baseline, intermediate, and final follow-up using 3D Slicer software. Measurements included IVC diameters at the filter apex, midpoint, and base, filter tilt angle from the caval axis, cross-sectional area at the base of IVC filter, and IVC segmental volume. Complications were defined as migration ( >10 mm), strut penetration ( >3 mm beyond IVC wall), and fracture. Associations with patient demographics, filter type, and dimensional changes were assessed.

Results: The baseline CT scan was obtained at a median of 30 days post-placement, and the median follow-up was 5.7 years (range 4.2-9.5). The filter types and indications are mentioned in Table 1. No immediate adverse events were noted.

Progressive IVC remodeling was observed: IVC diameter decreased from 19.4 ± 2.6 to 17.7 ± 2.9 mm at the apex (p=0.46), and 21.3 ± 3.2 to 17.7 ± 3.6 mm at the base (p=0.05). Similarly, filter tilt angle increased from 7.8° ± 2.3 to 12.9° ± 3.8 (p=0.16).

Overall, 7/31 (22.6%) patients developed complications: 4 migration (12.9%), 6 penetration (19.4%), and 1 fracture (3.2%). IVC diameter reduction at the base (11.5% vs 4.6%, p=0.04), greater increase in filter tilt (9.3° vs 4.2°, p=0.03), greater decrease in surface area of IVC at the filter base (13.6% vs 5.1%, p=0.03), and greater reduction of IVC segmental volumes (22.1% vs 9.4%, p=0.04) were all associated with development of complications. No associations with filter type, indication, age, or sex were noted.


Conclusion: Progressive caval remodeling and increasing filter tilt were associated with long-term complications after prolonged IVC filter dwell times. Serial volumetric CT analysis may help identify patients at risk and guide surveillance strategies.