Symptomatic abdominal aortic aneurysm occurred with transposition of the inferior vena cava. This anomaly may give rise to intraoperative complications. In this condition the adherence of the veins is found under the left iliac artery and the vena cava crosses the aorta cephalad to the renal arteries. If not suspected, both may be inadvertently injured. In this case a very short right renal vein crossed the aorta close to the aneurysm and made the proximal anastomosis difficult. The caval system in our patient corresponds to the level of development in the 45-mm human embryo. The aneurysm was successfully resected and the patient has continued to do well.
Dupont J. Isolated Left-Sided Vena Cava and Abdominal Aortic Aneurysm. Arch Surg. 1971;102(3):211–212. doi:10.1001/archsurg.1971.01350030049013