Identification of Bleeding Sources During Removal of Inferior Vena Cava Tumor Thrombi: Multidetector Computed Tomography Study

Abstract

Objectives: The purpose of this study was to investigate the sources of bleeding from the lumen of the inferior vena cava (IVC) during removal of the tumor thrombus. We have studied the multidetector computed tomography (MDCT) anatomy of the posterior tributaries of the IVC, including variant lumbar veins and lumbar veins of the infrarenal IVC. Materials and Methods: The retrospective study included 302 patients who underwent the bolus contrastenhanced MDCT of the abdomen for various indications. We analyzed the anatomy of the variant lumbar veins and infrarenal IVC lumbar veins. Results: Variant lumbar veins were detected in 50% of patients (151 out of 302). The diameter of these vessels ranged from 1 mm to 5 mm and averaged 2.5 mm. The distance from the upper edge of the right renal vein mouth to the variant vein mouth varied from 0 mm to 51 mm and averaged 13.7 mm. In 71% of cases the variant veins entered the subhepatic IVC. In 26.3% of cases it drained at the level of the upper edge of the renal vein mouths (cavarenal segment) and only in 2% of cases—to the retrohepatic IVC. Lumbar veins entered the IVC immediately next to the lower edge of the right renal vein mouth in 35 (11.6%) cases. Their average diameter was 4.7 mm. On the left side of the "risk zone" the lumbar veins drained only in 2 (0.7%) patients at a distance of 7 mm and 8 mm from the mouth of the left renal vein. Conclusion: The variant lumbar veins rarely are the main source of bleeding during thrombectomy. From our point of view, the right upper lumbar veins of the infrarenal IVC draining into the inferior vena cava in close proximity to the mouths of the renal veins played the leading role in this matter.