Prospective Anatomic Study of the Inferior Vena Cava and Renal Veins: Comparison of Selective Renal Venography with Cavography and Relevance in Filter Placement

Purpose: To compare the sensitivity of selective renal venography with that of cavography in the detection of variant anatomic structures of the renal vein that may affect the placement of inferior vena caval (IVC) filters and to define IVC dimensions. Patients and Methods: Flush cavography, selective bilateral renal venography, and bilateral iliac venography were performed in 108 patients referred for IVC filter placement or vena cavography. Infrarenal IVC length and width were determined with a sizing catheter during cavography. Anomalies were considered significant if they altered placement or selection of the vena caval filter or if they represented a potential collateral pathway for clot to bypass a filter. Results: Variant anatomic structures in the renal vein were found in 11% of patients with cavography and in 37% of patients with selective renal vein injection. Detected anomalies included circum-aortic veins (n = 11), multiple veins (n = 25), retroaortic veins (n = 2), and a partially duplicated IVC (n = 1). Selective venography depicted anomalies not suspected at standard cavography in 28 cases (26%); in 20 cases (18% of population) they were significant. The average infrarenal width was 20 mm on the anteroposterior view and was 17 mm on the lateral projection. Conclusion: IVC anomalies are common, and selective renal venography can depict significant anomalies in renal vein anatomic structures not shown at standard cavography.