The portal venous system comprises of the portal vein and the veins that start from the stomach, intestine, spleen and pancreas and merge into the portal vein. This portal vein branches out into smaller tributaries to pass through the liver. Increased resistance from the systemic venous system forces the blood to flow through alternate channels causing hepatic venous pressure which is elevated. When does not flow properly through the liver, the vessels in the liver are blocked. There is high blood pressure in the veins of the liver the result is swollen veins or varices in the esophagus, stomach, rectum and umbilical area. These varices rupture and cause internal bleeding which can be life threatening. When there is obstruction in the liver the pressure in the portal vein increases. The obstructions are classified as Prehepatic, intrahepatic and posthepatic portal hypertensions.
- Intrahepatic hypertension Cirrhosis and hepatic fibrosis scarring are primary intrahepatic causes of portal hypertension. Other illnesses that could lead to portal hypertension are fatty liver, alcohol abuse, hepatitis B and C infections, Wilson’s disease, cystic fibrosis, hemochromatosis, primary sclerosing cholangitis, biliary atresia and schistosomiasis.
- Prehepatic hypertension The prehepatic causes are portal vein thrombosis and congenital portal vein atresia.
- Posthepatic hypertension The posthepatic causes of portal hypertension are hepatic vein thrombosis, inferior vena cava thrombosis and restrictive pericarditis.
Some common symptoms of portal hypertension are:
- Varices Blood gets redirected and gathers into other veins making its way to the heart. The veins are swollen and enlarged.
- Esophageal gastric varices This can be life threatening with symptoms of hematemesis, tarry and bloody stools.
- Hepatic encephalopathy The liver is unable to filter waste products and these get accumulated, causing lethargy and confusion.
- Ascites Due to decrease of protein in the body, there is abnormal fluid collection within the peritoneum.
- Splenomegaly Blood and blood components are trapped in the spleen causing enlargement of spleen.
Surgical intervention for portal hypertension is considered only when methods to control varices such as sclerotherapy, latex banding and balloon tamponade fail to control the bleeding. There are at least two decompression procedures that can be considered:
- Proximal Spleno-renal shunt In a majority of Indians spleen needs to be removed because of hyprsplenism and a splenic vein end to renal vein side can be done especially in the non-cirrhotic variety of portal hypertension
- Distal splenorenal shunt (DSRS) This is a standard procedure used for decompression of gastroesophageal varices. A subcostal incision is made and a fixed retractor is used for improved intra-abdominal access. The splenic vein is identified and detached from the portal vein. This is then anastomosed to the left renal vein.
- Transjugular intrahepatic portosystemic shunt (TIPS) A tubular connection is placed within the liver using x-ray guidance, joining two veins in the liver. This is commonly called a stent. The procedure is usually done under general anesthesia. After an incision is made in the area, the internal jugular vein is first identified. With the help of x-ray guidance a catheter is passed into the liver into the hepatic vein. A contrast material is then injected into the hepatic vein to plan placement of TIPS stent. Under fluoroscopy, a stent is placed connecting the portal vein into the hepatic vein. A balloon is inflated and the stent is expanded in place.
- Orthotopic liver transplantation (OLT) A bilateral subcostal incision or a J incision is made for exposure of the liver. The hepatic hilum is dissected to prepare for native liver removal. The common area of anastomoses is the hepatic artery and the gastroduodenal artery. Preserving the longitudinal vessels supplying the common bile duct, the portal vein is transected. Once the native liver is removed, the graft liver is implanted.
Liver donations have their own criteria such as:
- Age of donor between 18 and 60 years old
- Donor should be in good health
- Donor should have a matching blood type
- Donor should undergo several tests before being considered fit for the transplant.