Significance of blood flow in the inferior and superior mesenteric veins for the formation of oesophageal varices.

The degree of involvement of blood flow in the superior mesenteric vein and inferior mesenteric vein in the formation of oesophageal varices is not known. We have developed a method by which the contributions of these veins to portal blood flow can be evaluated simultaneously in a relatively non-invasive way. An enteric-coated capsule containing [123I]iodoamphetamine (IMP) is given by mouth and 3 h later [123I]IMP is instilled into the rectum. The data obtained are treated by computer to calculate the portal shunt index via the inferior and superior mesenteric veins. In chronic hepatitis and cirrhosis, when varices were absent, the difference in these indices was not significant. In the presence of varices, the portal shunt index via the inferior mesenteric vein was significantly higher than that via the superior mesenteric vein. It was suggested that the contribution of blood flow in the inferior mesenteric vein the portal/splenic axis is important in the formation of varices.