Plate 171

Portal decompression is indicated in patients who have portal hypertension complicated by gastrointestinal hemorrhage from esophageal varices that are not effectively controlled with sclerotherapy injections. Some procedures completely interrupt portal venous flow to the liver (end-to-side portacaval shunt), while others selectively decompress the portal system via a collateral shunt (side-to-side portacaval, splenorenal, and mesocaval). The procedure selected will depend upon the patency of the portal and splenic veins, the results of liver function studies, the amount of portal venous blood being shunted, and whether the patient is bleeding acutely.

Selection of patients should be based on their clinical status, results of liver function studies, and interpretation of hepatic hemodynamics as determined by radiologic studies. Patients considered for shunting procedures generally should be under 60 years of age. Ideally, there should be no evidence of encephalopathy, jaundice, ascites, or muscle wasting. Serum albumin should be above 3 g/dL, prothrombin time greater than 1.5 times normal, and sodium sulfobromophthalein below 30% at 30 minutes. Deviation from these criteria does not absolutely contraindicate surgery, but the surgical risk is directly proportional to the degree of hepatic decompensation. Finally, liver transplantation may be considered.

Shunting procedures for portal hypertension can be divided into three types: portacaval, splenorenal, and mesocaval. Figures A, B, C, D, E, and F show diagrammatically the basic surgical choices for diversion of the portal venous flow.

The primary indication for portacaval shunt is the control of massive upper-gastrointestinal hemorrhage from varices which cannot be controlled with endoscopic ablation or when transjugular intrahepatic portosystemic shunts (TIPS) are not available. Portacaval shunts are sometimes preferred when there has been prior splenectomy, splenic vein thrombosis, reversal of flow in the portal vein, thrombosed splenorenal shunt, ascites, or hepatic vein thrombosis. The selection of a direct portacaval shunt, of course, depends upon the demonstration of a patent portal vein preoperatively or at laparotomy.

The side-to-side anastomosis (Figure A) has been preferred by some in the presence of portal hypertension with no evidence of a rise in pressure on the hepatic end of the temporarily occluded portal vein. This suggests that the arterial blood supply is going through the liver and that lowering of the portal pressure by the side-to-side anastomosis with the vena cava will not result in diversion of the arterial supply to the liver. Another advantage of this type of shunt is that it decompresses the hepatic sinusoids, and this may be beneficial in the treatment of patients with intractable ascites accompanied by variceal hemorrhage.

The usefulness of the portacaval shunt in the treatment of refractory ascites is not accepted universally, although several studies have suggested that this is an effective mode of therapy. If shunting is indicated to control ascites, the side-to-side shunt or double end-to-side shunt is usually preferred. This is particularly true in unusual cases of hepatic vein thrombosis (Budd-Chiari). No decompressive procedure on the portal system has any beneficial effect on liver function. The end result of any such operation, therefore, will depend largely upon the progress of the basic liver disease.

The end-to-side portacaval shunt (Figure B) is the procedure of choice in patients who have had a prior splenectomy, splenic vein thrombosis, or thrombosis of a splenorenal shunt and in those patients who have reversed flow in the portal vein. In this procedure the portal vein is ligated in the hilus of the liver, and the distal portion of the portal vein is anastomosed to the inferior vena cava. This shunt is particularly indicated when there is no evidence of ascites and when portal blood flow is reversed in the hepatoportal direction, as determined by a rising pressure in the hepatic end of the temporarily occluded portal vein. With the end-to-side anastomosis, all of the portal venous blood flow is shunted from the liver, while hepatic artery flow to the liver is preserved.

See Plates 172 and 173 for details of the portacaval shunting procedures.

In the presence of extrahepatic block of the portal vein, secondary hypersplenism, prior biliary surgery, and/or cavernomatous changes of the portal vein, a shunt between the splenic vein and left renal vein may be the procedure of choice, provided the splenic vein is patent and of adequate size. If it is necessary or desirable to remove the spleen, a conventional splenorenal anastomosis (Figure C) may be performed. The distal splenorenal shunt (Warren shunt, Figure D) retains the spleen and, while selectively decompressing the esophageal varices, allows maintenance of portal pressure and perfusion of the liver, thus providing protection against hepatic encephalopathy. This shunt is particularly indicated in the presence of normal liver function, high volume of portal flow to the liver, minimal hepatocellular disease, marked splenomegaly, or idiopathic portal hypertension. The procedure consists of dividing the splenic vein at its junction with the superior mesenteric vein, ligating the proximal portion of the vein, and anastomosing the distal portion to the left renal vein. As an alternative to dividing the splenic vein, an interposition graft may be anastomosed between the splenic vein and the left renal vein, with ligation of the splenic vein proximal to the graft as well as ligation of the coronary and right gastroepiploic veins.

See Plates 175 and 176 for details of the Warren splenorenal shunting procedures.

In most instances portal decompression may be accomplished by portacaval or splenorenal shunt procedures. However, the Clatworthy mesocaval shunt (Figure E) is necessary in patients who have undergone splenectomy and have either thrombosis or cavernomatous changes of the portal vein. The mesocaval shunt is advisable in patients with excessive bleeding at surgery from periportal or perisplenic vessels. Finally, it should be the procedure of choice in small children in whom the splenic and/or portal veins may be too small for a successful procedure (minimal size approximately 1 cm in diameter). Elective shunts in children should be postponed, if possible, until the age of 4 years. The procedure consists of division of the superior vena cava and anastomosis side to end with the superior mesenteric vein.

In cases of emergency, a lesser technical procedure without division of the inferior vena cava can be accomplished by the interposition of a large knitted Dacron graft between the vena cava and superior mesenteric vein at the level of its first branches (Figure F). This modification of the mesocaval shunt (interposition mesocaval shunt or Drapanas shunt) offers the advantages of a simplified technical approach with minimal blood loss.

The details of mesocaval shunting procedures are shown in earlier editions of this atlas.

Active bleeding from esophageal varices in patients is usually controlled by sclerotherapy. An alternate approach is to introduce a stapling device into the lower esophagus through an anterior gastrotomy opening. The esophageal wall is compressed between the two components of the stapler by an encircling 00 silk ligature. When the stapler is fired, a complete transection of the esophagus occurs with excision of a narrow ring of esophagus. Additional sutures may be taken about the anastomosis for added security. Since the vagus nerves are divided, a pyloroplasty is performed. The splenic artery as well as the coronary vein may be ligated.