Tomographic anatomy of the vena cava and renal veins: features relevant to vena cava filter placement

Abstract

BACKGROUND: There is a growing demand for invasive procedures involving the inferior vena cava, in particular for placement of vena cava filters. It is not always easy to identify the more distal renal vein with cavography, for safe release of filters. OBJECTIVES: To determine parameters for the relationships between the renal veins and the infrarenal vena cava and their corresponding vertebral bodies, their relationships with biotype and the occurrence of anatomic variations, the relationships between vertebral bodies and the bifurcation of the common iliac veins and the distance from this bifurcation to the outflow of the more distal renal vein, with reference to placement of vena cava filters. METHODS: A total of 150 abdominal computed tomography scans conducted from October to November 2011 were analyzed and classified according to the biotype exhibited (using Charpy's angle). Scans were performed at MEDIMAGEM and analyzed at the Integrated Vascular Surgery Service, both part of Hospital da Beneficência Portuguesa in São Paulo, Brazil. RESULTS: In 127 of the 150 scans analyzed (84.66%), the more distal renal vein emerged between the first lumbar intervertebral space (L1-L2) and the body of L2, irrespective of patient biotype. Just 23 patients (15.33%) exhibited a more distal renal vein with outflow below the body of L2, i.e. in the projection of the space between L2 and L3. CONCLUSIONS: The radiological correlation between the confluence of the more distal renal vein and vertebral bodies exhibits little variation, irrespective of the biotype of the patient.