To the Editor: Pathophysiology of Splenic Arteriovenous Fistula.

A splenic arteriovenous fistula causes a "prehepatic" hypertension in the portal venous system with the double mechanism of an increased blood amount and mainly its high pressure inflow. It aggravates for a secondary fibrosis of the portal vein branches and "capillarization" of the hepatic sinusoids, adding a further "intra-hepatic" component. The subsequent development of portosystemic collaterals induces the risk of gastrointestinal hemorrhages All this suggests to perform a close monitoring of every case of splanchnic aneurysm or pseudo-aneurysm, through the current cross-section imaging tools, for their possible evolution in an arteriovenous fistula, and to consider an early therapy, also endovascular, before any secondary damage of the liver parenchyma. In this case the treatment of the portal vein hypertension can be "ethiological" and resolutive.