Oesophageal Variceal-Pulmonary Venous Fistula A Rare Cause of a Right-to-Left Shunt

Oesophageal varices are a dilated submucosal venous plexus in the lower third of the oesophagus which result from increased pressure in the portal venous system. The portal system is connected to the systemic circulation in specific locations referred to as sites of portosystemic anastomosis. An increase in portal venous pressure is therefore reflected at these anastomotic sites, causing manifestations such as oesophageal varices, rectal varices, caput medusae and splenorenal shunts. Varices do not cause symptoms until they leak or rupture and this is the main complication which requires prompt treatment. Here, we present a post-liver transplant patient with metastatic hepatocellular carcinoma who had oesophageal varices that fistularized with a left pulmonary vein, thus creating a right-to-left shunt. Right-to-left shunts are usually intracardiac or intrapulmonary in location. The complications of a right-to-left shunt include predominantly hypoxia, cyanosis and, sometimes, paradoxical emboli in the case of intracardiac shunts. This patient had a very uncommon cause of such a shunt caused by a direct fistulous connection. LEARNING POINTS: Right-to-left shunts create a ventilation-perfusion mismatch. Recognizing situations where there is a connection between the systemic circulation and pulmonary circulation without intermediate oxygenation is important because of possible clinical implications such as hypoxia.