Hepatopulmonary syndrome and portopulmonary hypertension

The incidence of pulmonary vascular disorders is significantly increased in patients with liver disease. Intrapulmonary shunting with hypoxemia in patients with liver disease is diagnosed as hepatopulmonary syndrome (HPS), whereas precapillary pulmonary vessel obliteration is identified as portopulmonary hypertension (PPHTN). Because the symptoms of liver disease can mimic those of pulmonary vascular disease, all patients with hepatic failure should be screened for these two diseases. Pulse oximetry effectively screens for hypoxemia associated with HPS, whereas an elevated right ventricular systolic pressure estimated by echocardiography identifies patients at risk of having PPHTN. Liver transplantation is the only effective medical therapy for HPS. However, those who have a resting arterial oxygenation less than 50 mm Hg or a shunt measured by scintigraphic perfusion greater than 20% have an unacceptably high mortality rate following surgery. Compared with HPS, there are more therapeutic options that can bridge patients with PPHTN to transplantation. Drugs used to manage idiopathic pulmonary hypertension have shown promise in the treatment of PPHTN. Prostanoids, endothelin receptor antagonists, and phosphodiesterase-5 inhibitors have improved transplant survival. Despite treatment, however, perioperative mortality for patients with PPHTN remains high. Even with successful transplantation, HPS and PPHTN can persist or develop de novo. Long-term follow-up and surveillance of liver transplant recipients is thus indicated to identify HPS and PPHTN following surgery.