Angiographic demonstration of portocaval and other decompressive liver shunts.

Abstract

Several angiographic technics have been developed to study portocaval, splenorenal, and mesocaval shunts. The disadvantages of most of these methods, however, have prevented their general acceptance. Surgical technics, including operative superior mesenteric venography (7) and operative portal venography (1), must be performed under general anesthesia either immediately prior to a definitive operative procedure or as an isolated examination. Since serial filming is usually not available in the operating room, dynamic blood flow information cannot be obtained. While splenoportography will demonstrate some types of portocaval shunts and idiopathic splenorenal shunts, it is of no use in the evaluation of portocaval shunts in which the spleen has been removed, of mesocaval shunts, or of operative splenorenal shunts. The risk of bleeding and emergency splenectomy following splenoportography must be considered. Boijsen and Efsing (2) have shown that splenoportography in patients with portal hypertension may lead to the development of intrasplenic aneurysms along the needle tract. Also, reversal of blood flow in the splenic vein in the presence of severe portal hypertension may simulate splenic vein occlusion (6). Percutaneous transhepatic venography (12) will generally demonstrate only the intrahepatic portal system unless there is severe cirrhosis with reversal of blood flow. Risk of bleeding exists following this procedure since the injection of contrast medium into a portal radical must be forceful and accidental injection into the parenchyma can lead to liver damage. Umbilical venography (9), which requires a minor surgical procedure, has been successfully used as a substitute for splenoportography in evaluating the portal venous system. The main disadvantage for demonstrating decompressive liver shunts is that the contrast medium is directed toward the intrahepatic portal system. In patients with portal hypertension, reflux frequently occurs into the extrahepatic portal vein and its venous collaterals. Demonstration of side-to-side portocaval shunts and splenorenal shunts by this procedure should be possible, although this has not been reported. Arterial portography (3) is the most straightforward approach to shunt demonstration, but the venous opacification achieved by conventional superior mesenteric arteriography is inconsistent. Bron and Fisher (5) placed tourniquets on both thighs to decrease the venous return in the inferior vena cava. While this improved visualization of the inferior vena cava superior to the shunt, it did not increase the concentration of contrast medium in the superior mesenteric veins or venous collaterals. Nebesar and Pollard (10) performed arterial portography by selective splenic arterial injection. Occasionally, superior mesenteric arteriography was carried out, using up to 75 ml of 76 per cent Renografin2 to obtain adequate venous visualization.