Using umbilical vein portal phlebography, a group of patients, often with previously unsuspected liver disease or portal hypertension, have been identified with massive spontaneous portal-systemic shunts. In all cases, the collateral circulation was a single large vessel. The splenoadrenorenal, umbilical vein, or inferior mesenteric vein routes were the common pathways.
These natural shunts were functional and effective in the alleviation of portal hypertension without evidence of esophageal varices or other collaterals. Portal flow was usually retrograde, perhaps contributing to the small atrophic liver seen in all patients. Six such patients were seen in the last 40 studied. This phenomenon may be more common than suspected in the cirrhotic population and account in part for differences in natural history, complications, and results of surgical therapy.
Wexler MJ, MacLean LD. Massive Spontaneous Portal-Systemic Shunting Without Varices. Arch Surg. 1975;110(8):995-1003. doi:10.1001/archsurg.1975.01360140139027