THE HEPATOPULMONARY SYNDROME

Objective: To review current knowledge about the hepatopulmonary syndrome, including definition and clinical features, methods for diagnosing it, pathophysiologic mechanisms of the associated vascular dilatations, and considerations in treatment, with emphasis on potential reversibility of the syndrome after liver transplantation. Data Sources: The MEDLINE database from January 1986 to December 1993 and bibliographies of selected articles. Study Selection: Case studies and series reporting results from patients with the hepatopulmonary syndrome were reviewed. Clinical reviews and animal studies relevant to the hepatopulmonary syndrome were examined. Data Extraction: Outcomes, including survival and the frequency of reversibility of the hepatopulmonary syndrome, were extracted from available clinical reports. Data Synthesis: Mild hypoxemia is multifactorial and occurs in approximately one third of all patients with chronic liver disease. The hepatopulmonary syndrome is one cause of hypoxemia that may also cause dyspnea, platypnea, and orthopnea. Intrapulmonary vascular dilatations and the resulting right-to-left intrapulmonary shunt are characteristic of the syndrome. Pharmacologic treatment with almitrine bismesylate, somatostatin analog, and indomethacin and treatment with plasmapheresis have been disappointing. The underlying cause and the predictors of reversibility of the hepatopulmonary syndrome remain unknown, but it has recently been shown that such reversibility is possible and that contrast-enhanced echocardiography appears to be the most sensitive diagnostic test for detecting intrapulmonary vascular dilatations. Conclusions: In the context of persisting uncertainty about the cause and treatment of the hepatopulmonary syndrome, future studies must focus on better understanding the pathophysiology of the hepatopulmonary syndrome, predicting reversibility after liver transplantation, and identifying other treatment options.