Portopulmonary Hypertension

Portopulmonary hypertension (PPHT) is a respiratory complication of portal hypertension, defined as an increase in mean pulmonary artery pressure (PAP) of > 25 mmHg with an increase in pulmonary vascular resistance of > 240 dyn.s/cm-5 and a normal pulmonary capillary wedge pressure ( < 15 mmHg), which often occurs in subjects with liver cirrhosis. Histopathological features of PPHT are endothelial and smooth-muscle cell proliferation and fibrosis leading to luminal obstruction in the resistance arteries. The pathogenesis of PPHT may result from an imbalance between vasoconstrictor and vasodilating factors. The most common pulmonary symptom is exertional dyspnea; fatigue, chest pain and syncope occur more often at an advanced stage. Edema, ascites and prominent jugular veins are signs of both decompensated hepatic cirrhosis and right ventricular failure. Right heart catheterisation is the gold standard for the diagnosis and defines PPHT in mild disease with PAP less than 35 mmHg, moderate disease with PAP between 35 and 45 mmHg, and severe disease with PAP of 45 mmHg or higher. The medical treatment of portopulmonary hypertension is based on the treatment of other forms of pulmonary arterial hypertension, including vasomodulating pharmacologic agents. Liver transplantation is accompanied by high risk of mortality, generally due to acute right ventricular failure and cardiovascular collapse. The prognosis of PPHT is poor with mean survival of 15 months.