THE HEPATOPULMONARY SYNDROME

Objective: To review current knowledge about the hepatopulmonary syndr ome, including definition and clinical features, methods for diagnosin g it, pathophysiologic mechanisms of the associated vascular dilatatio ns, and considerations in treatment, with emphasis on potential revers ibility of the syndrome after liver transplantation. Data Sources: The MEDLINE database from January 1986 to December 1993 and bibliographie s of selected articles. Study Selection: Case studies and series repor ting results from patients with the hepatopulmonary syndrome were revi ewed. Clinical reviews and animal studies relevant to the hepatopulmon ary syndrome were examined. Data Extraction: Outcomes, including survi val 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. Phar macologic treatment with almitrine bismesylate, somatostatin analog, a nd indomethacin and treatment with plasmapheresis have been disappoint ing. The underlying cause and the predictors of reversibility of the h epatopulmonary syndrome remain unknown, but it has recently been shown that such reversibility is possible and that contrast-enhanced echoca rdiography appears to be the most sensitive diagnostic test for detect ing intrapulmonary vascular dilatations. Conclusions: In the context o f persisting uncertainty about the cause and treatment of the hepatopu lmonary syndrome, future studies must focus on better understanding th e pathophysiology of the hepatopulmonary syndrome, predicting reversib ility after liver transplantation, and identifying other treatment opt ions.