ARRS 2022 Abstracts

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E1921. Anatomical Variants and Vena Cava Filter Placement and Evaluation
Authors
  1. Kavish Gupta; Cedars-Sinai Medical Center
  2. Susan Win; Cedars-Sinai Medical Center
  3. Meng Geng; Cedars-Sinai Medical Center
  4. Kevin Hoang; Cedars-Sinai Medical Center
Background
Vena cava filters (VCFs) serve the important function of preventing pulmonary embolisms (PE) in patients with contraindications to anticoagulation, among other indications. Filter placement can be straightforward; however, a knowledge of caval anatomical variants is crucial to diagnostic assessment of filters and optimizing filter function.

Educational Goals / Teaching Points
By the end of this exhibit the reader will be able to recognize standard caval anatomy and filter placement, become familiar with anatomical variants of the vena cava and know the associated implications and techniques for filter placement.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Presence of a single right-sided vena cava makes standard infrarenal inferior vena cava (IVC) filter placement appropriate in the vast majority of patients. However, disruptions in normal embryological processes that involve involution of the primordial paired cardinal veins can result in numerous anatomical caval variants. The most common of these with implications for filter placement include duplicated IVC, retro-aortic renal vein, circumaortic renal vein, left-sided IVC, mega vena cava, and an interrupted IVC. Each has unique implications for filter evaluation, placement, and retrieval. Therefore, variants must be looked for and identified if present, both when placing filters and assessing filters on diagnostic studies. For example, in the case of a duplicated infrarenal IVC, a thrombus is able to circumvent an infrarenal filter placed in the right-sided IVC, which may result in pulmonary embolism. Strategies for dealing with this variant usually include placing bilateral iliac filters or one suprarenal filter. Further, variations on a duplicated IVC, such as hypoplasia of one of the IVCs, opens up the possibility of other techniques, such as embolization of the hypoplastic IVC and placement of an infrarenal filter in the primary IVC. Each of the aforementioned anatomical variants have their own unique considerations and associated techniques to optimize filter function.

Conclusion
Filter placement or evaluation without consideration of vena cava variants can have devastating consequences for patient care. Therefore, understanding anatomical caval variants and techniques for approaching filter placement in each is crucial to patient care.