ARTERIOPORTAL COMMUNICATIONS - OBSERVATIONS AND HYPOTHESES CONCERNING TRANS-SINUSOIDAL AND TRANS-VASAL TYPES

Arterioportal shunting is observed angiographically in a wide variety of pathologic conditions. The route of flow was classically via the hepatic sinusoids (transsinusoidal). This route occurs in cases of cirrhosis or the Budd-Chiari syndrome and results in retrograde hepatofugal flow in portal branches. More recently, a transvasal route was recognized angiographically, in which portal flow often remains hepatopetal. The transvasal route occurs in cases of hepatocellular carcinoma, metastases, shock, hepatic arterial obstruction and many other conditions. Histologic confirmation of this route was sought for many years, with partial success. Angiographic evidence is sufficiently compelling to justify description of this pathway and its significance. Arterioportal flow may also occur via a post-traumatic fistula (disruption of adjacent portions of hepatic artery and portal vein), and via benign tumor vessels in hemangioma or hemangioendothelioma.