Hepatopulmonary syndrome

HPS occurs when pulmonary microvascular dilatation impairs arterial oxygenation in the setting of liver disease or portal hypertension. The syndrome is found in as many as 20% of cirrhotics and should be considered in any patient with chronic liver disease who develops dyspnea or hypoxemia. Recognition is important, because the presence of HPS increases mortality in the setting of cirrhosis. Contrast echocardiography and standard cardiopulmonary testing are generally sufficient to make the diagnosis of HPS, but further testing may be needed in patients who have both intrinsic cardiopulmonary disease and intrapulmonary vasodilatation. Treatment consists of supplemental oxygen and consideration of orthotopic liver transplantation if significant hypoxemia is present. The recognition in experimental models that a sequence of molecular alterations leads to endothelin-1 and TNF-α modulation of pulmonary microvascular tone may lead to the development of novel and effective medical therapies.