Hepatopulmonary syndrome

Hepatopulmonary syndrome (HPS) is a pulmonary vascular disorder characterized by altered gas exchange due to intrapulmonary vascular dilatations occurring in the setting of hepatic dysfunction, usually with portal hypertension. The hallmark of HPS is hypoxemia and intrapulmonary shunting of blood, with the diagnosis being made based on a constellation of clinical, laboratory, and imaging data. HPS is defined by: (1) the presence of liver disease, usually with cirrhosis and portal hypertension; (2) abnormal arterial oxygenation, with an alveolar-arterial gradient ≥ 15 mmHg (or ≥ 20 mmHg in patients ≥ 65 years of age) or an arterial partial pressure of oxygen less than 80 mmHg while breathing room air based on arterial blood gas sampling; (3) evidence of intrapulmonary shunting on transthoracic echocardiography with injection of agitated saline; and (4) the absence of cardiopulmonary disease that would otherwise cause hypoxemia. HPS has important clinical implications in regard to impaired patient quality of life and increased posttransplant mortality. There are currently no treatments approved for the treatment of HPS, and the only widely accepted curative option for HPS remains liver transplantation. Resolution of hypoxemia and normalization of pulmonary function have been well documented after transplantation in patients with HPS. Posttransplant outcomes are very good for transplant recipients with HPS, although there are data to suggest worse outcomes in those with more severe hypoxemia.