Portal Pseudoperfusion

Abstract

The hemodynamics following interposition mesosystemic shunts is unclear. Portal venous perfusion may continue after interposition mesocaval shunts. In 1971 a prospective randomized trial comparing the distal splenorenal shunt with a variety of interposition mesosystemic shunts (primarily mesocaval or mesorenal) was begun. Visceral angiography was used to assess early and late postoperative hemodynamic changes after selective and nonselective shunts. None of the patients with patent interposition shunts retained portal perfusion preoperatively. Angiographic studies were performed on 2 patients. Both had excellent portal perfusion preoperatively but after interposition shunting (1 mesocaval and 1 splenocaval) neither maintained liver portal perfusion. Celiac artery injections produced opacification of the entire splenoportal axis; such portal venous opacification occurred in retrograde direction by selective hepatic arterial injections showed hepatofugal portal venous flow. Two nonrandomized patients received interposition mesorenal shunts and exemplify this phenomenon (portal pseudoperfusion). Misinterpretation of venous phase celiac and nonselective superior mesenteric arteriography in determining the direction of portal flow probably causes the confusion about interposition mesosystemic shunt hemodynamics. Preoperative and postoperative angiograms of 4 patients clarify the mechanism of portal pseudoperfusion and show that interposition shunts totally siphon venous perfusion. Detection of the phenomenon and techniques to avoid it are presented.