Occlusion of the Hepatic Veins
Classical Budd-Chiari syndrome refers to occlusion of the hepatic veins. Symptoms may include abdominal pain, hepatomegaly, jaundice, fever, and liver dysfunction. In about half of the patients the caudate lobe is markedly enlarged because drainage via the right hepatic vein is preserved. Liver histology shows centrilobular and sometimes midlobular involvement with sinusoidal congestion, hepatocyte atrophy, and fibrosis.

The severity of the disease is proportionate to the extent of involvement of the hepatic veins, the time-course over which the obstruction develops, and the duration of untreated disease. Slower development of the occlusion allows the formation of collaterals, which alleviates sinusoidal congestion. Duration of the disease less than 16 weeks is usually associated with better preservation of liver histology and function. The most severe presentation is fulminant hepatic failure with coagulopathy, encephalopathy, and hepatorenal syndrome. More commonly the patient will present with ascites, mild to moderate impairment of liver function, and a variable degree of centrilobular fibrosis on biopsy. Patients with extensive intrahepatic collaterals or involvement of a single hepatic vein may have no ascites and no impairment of liver function. Obstruction of the hepatic veins may be asymptomatic in up to 25% of the cases.

Causes of Budd-Chiari are listed in the accompanying table. Primary myeloproliferative disorders are the most common association, but inherited prothrombotic tendencies have been frequently reported etiologies. A wide variety of other disorders may cause Budd-Chiari through either predisposition to thrombosis or through mechanical obstruction of the veins. It is common to have more than one predisposing factor. Hematologic evaluation is usually necessary and useful.

Ultrasound may show enlargement of the caudate lobe, intrahepatic collaterals, echogenic areas consistent with occlusion of hepatic veins, and ascites. Doppler ultrasonography can detect abnormality of venous flow with high accuracy and this may be sufficient to establish the diagnosis. The diagnosis can be made by hepatic venography.

In fulminant liver failure, the treatment of choice is liver transplantation. Overall success rates of 70% have been reported. Post-transplantation there is a high rate of recurrence of Budd-Chiari unless the patient is maintained on long-term anticoagulation. Case reports have described recurrent Budd-Chiari in patients who had a period of subtherapeutic anticoagulation.

Multivariate analyis has demonstrated that survival is inversely correlated with age, response to diuretics, Child-Pugh score, and serum creatinine. There is a high mortality rate among those with poor prognostic factors, which does not seem to be influenced by either medical or surgical management. Liver transplantation may be the only approach in these patients.

Current data suggest that decompressive approaches may not alter ultimate survival. Spontaneous improvement in symptomatic patients has been described, but this is probably uncommon. Refractory ascites or variceal hemorrhage may be managed by portal-systemic shunt in patients with good prognostic factors. Transjugular intrahepatic portocaval shunt (TIPS) is an effective alternative in some patients since it avoids surgery at the hepatic hilum if transplantation should become necessary. However, anticoagulation after TIPS is controversial.

Occlusion of the hepatic portion of the inferior vena cava
In the West, classic Budd-Chiari is more common than obstructive disease affecting the hepatic portion of the inferior vena cava (IVC). However, in developing countries the latter is more common. There are a variety of anatomical presentations of the membranous obstruction within the IVC. The original theory was that the membrane was congenital, but current thinking is that it is a consequence of thrombus organization. It has been suggested that one of the risk factors in developing countries for the initiating thrombophlebitis or thrombosis may be an infectious process. Obstruction of the IVC across the hepatic portion has also been described in patients with a predisposition to thrombosis, e.g. vasculitis or primary myeloproliferative disorder. Although this particular section of the IVC is clearly more vulnerable to thrombosis, the reason is unknown.

A prominent clinical feature of IVC obstruction is the presence of collateral venous circulation in the abdomen, back, and chest. Ultrasound may demonstrate obstruction or stenosis of the inferior vena cava, while MRI may be useful in delineating occluding membranes.

Portocaval shunt is not indicated, but surgical management has commonly been by cavoatrial or mesoatrial shunt. If the occluding membrane is thin, angioplasty may be the treatment of choice. TIPS has been used as an alternative to portosystemic shunt.