Hepatopulmonary syndrome and portopulmonary hypertension. Swiss Med Wkly 2003

Liver disease affects the lungs. The most com-mon pulmonary consequence of liver disease is al-tered gas exchange resulting in hypoxaemia. This has been termed the “hepatopulmonary syn-drome”. Liver disease is sometimes associated with an abnormal increase in pulmonary vascular re-sistance (PVR), resulting in pulmonary hyperten-sion. This has been named “portopulmonary hy-pertension”. The common determinant of the he-patopulmonary syndrome and portapulmonary hypertension is portal hypertension and portosys-temic shunting. Most cases of portal hypertension develop as a consequence of liver cirrhosis. Liver disease affects the lungs. The majority of patients exhibit mild to moderate arterial hypox-aemia essentially attributable to an alteration in ventilation/perfusion matching and limited by an increase in ventilation. A minority (some 10%) of patients exhibit a “hepatopulmonary syndrome” defined by severe hypoxaemia with arterial PO2 below 60 mm Hg, dyspnoea, cyanosis, digital club-bing, orthodeoxia, platypnoea and demonstrable pulmonary vascular dilatations causing a true pulmonary shunt and a diffusion/perfusion imbal-ance. The hepatopulmonary syndrome is incur-able but resolves over time after liver transplanta-tion. An even lower proportion of patients, ap-proximately 1%, develop pulmonary hyperten-sion. Clinically this “portopulmonary hyperten-sion ” resembles primary pulmonary hypertension, with dyspnoea and fatigue as the main symptoms, histopathology and response to prostacyclin ther-apy. Portopulmonary hypertension is irreversible. Liver transplantation mortality in patients with portopulmonary hypertension ranges from 50 to 100%. The common cause of the hepatopul-monary syndrome and portopulmonary hyperten-sion is portal hypertension and portosystemic shunting, indicating that vasoactive and angio-genetic factors originating from the liver normally control the pulmonary circulation. Key words: liver cirrhosis; portal hypertension; hy-poxaemia; pulmonary hypertension; hepatopulmonary syndrom