Physiopathological, clinical and therapeutic aspects of hepatopulmonary syndrome

Patients with cirrhosis or portal hypertension may develop hepatop ulmonary syndrome (HPS) and portopulmonary hypertension (PPHT). HPS occurs in 25% of the subjects with cronic hepatopathy waiting for a liver transplantation. HPS is characterized by cronic hepatopathy and/or portal hypertension, increased P(A-a)O2 gradient (>20 mmHg) with hypoxemia and intrapulmonary vascular dilatations without a primary cardiovascular disease. Hypoxiemia is due to intrapulmonary arteriovenous shunts and to dilatation of microvessels in basal parts of the lung and of pleural vessels. In patients with cirrhosis an impaired cardiovascular function is frequent, often in a subclinical phase of the disease. Left ventricular systolic and diastolic dysfunction may develop a cronic hepatopathy and the relation between right ventricular and liver failure has been studied. During cirrhosis characteristic alterations of systemic hemodynamic can cause the hyperdynamic circulatory syndrome. Contrast enhanced 2D ECHO cardiography is the preferred screening test for intrapulmonary arteriovenous shunts. The aim of HPS therapy is to contrast intrapulmonary vasodilatation, increased portal flux and hyperdynamic syndrome. New therapeutical agents are fosfodiesterase inhibitors, ET-1 receptor antagonists and selective NOS inhibitors. However, medical treatment is not much effective in HPS and liver transplantation is considered the only therapeutical chance