What is Budd Chiari syndrome?

Budd chiari syndrome (BCS) is a disease characterized by obstruction of the hepatic venous outflow tract which is the main channel taking blood from the liver to the heart. Liver receives the blood supply from the portal vein and hepatic artery. After circulating through the liver, the blood then flows out via the hepatic veins to the inferior vena cava (large blood vessel emptying into the heart). There are total three hepatic veins. The obstruction to the blood flow can be in the hepatic veins or in the inferior vena cava. If the obstruction is in the smaller veins of liver (hepatic venules), then it is called as sinusoidal obstruction syndrome.