Left-sided inferior vena cava in patients submitted to aorto iliac surgery. Our experience and review of the literature.

We present two cases of left sided inferior vena cava, one unexpectedly observed during an operation of aorto bifemoral bypass in a patient with severe Leriche syndrome and almost complete obstruction of the infrarenal aorta, the second in a patient with an aneurysm of the abdominal aorta, in whom the anomaly was recognized before the operation. This very rare congenital malformation (0.2-0.5%) was not recognized in the first patient by the duplex scanner performed preoperatively, probably because of the low level of suspicion carried on by an experienced operator. Computer tomography angiography or magnetic resonance angiography, which would have surely shown us the anomaly, were not done in the first patient because, in the lack of an aneurysmal disease or other abdominal pathological situations, these investigations were not required before operation. The possible hazards of such an unrecognized malformation are great, mostly in terms of uncontrollable intraoperative hemorrhages, but the final outcome of this case was positive.