Hepatopulmonary Syndrome. Review

Abstract

Liver cirrhosis is often accompanied by complications from the pulmonary system. These include hydrothorax, portopulmonary hypertension and hepatopulmonary syndrome. Hepatic hydrothorax affects about 6-10% of patients with end-stage disease, which results in the passage of ascetic fluid into the pleural space through diaphragm defects. The common cause of the hepatopulmonary syndrome and portopulmonary hypertension is portal hypertension and portosystemic shunting, indicating that vasoactive and angiogenetic factors originating from the liver normally control the pulmonary circulation. Portopulmonary hypertension is like pulmonary arterial hypertension, which develops against the background of portal hypertension as a result of chronic liver disease or without other causes of increased pressure in the pulmonary vessels. The prevalence of portopulmonary hypertension ranges from 2% to 8.5% among patients with portal hypertension and is associated with a poor prognosis. Hepatopulmonary syndrome is characterized by intrapulmonary dilatation of microvessels, which causes intrapulmonary shunting and leads to impaired gas exchange in liver diseases, and is associated with a decrease in the quality and duration of life in patients with cirrhosis. Nitric oxide overproduction and angiogenesis seem to be the hallmarks of a complicated pathogenetic mechanism, leading to intrapulmonary shunting and ventilation-perfusion mismatch. A classification of hepatopulmonary syndrome according to the severity of hypoxemia has been suggested. Hepatopulmonary syndrome includes a triad: hepatic dysfunction and / or portal hypertension, dilatation of intrapulmonary vessels, and increased alveolar-arterial oxygen gradient. The prevalence of hepatopulmonary syndrome varies depending on the study groups from 5% to 30%. The most common symptom of the complication is shortness of breath, but in most cases, hepatopulmonary syndrome is asymptomatic. A decrease in oxygen saturation less than 96% corresponds to a decrease in PaO2<70 mm Hg and testifies to the possible development of hepatopulmonary syndrome. In the case of a positive screening, the patient should undergo arterial blood gas analysis, which helps to determine PaO2 and alveolar to arterial oxygen gradient. Conclusion. Contrast-enhanced echocardiography with agitated saline is the gold standard in the diagnosis of intrapulmonary dilatation. The only effective treatment for hepatopulmonary syndrome is liver transplantation. Complete recovery of hepatopulmonary syndrome after liver transplantation is observed within a year in most patients with cirrhosis and hepatopulmonary syndrome