Portopulmonary hypertension

Portopulmonary hypertension is a serious complication of portal hypertension that is associated with significant mortality. It refers to the presence of pulmonary arterial hypertension in patients with portal hypertension. The severity of portopulmonary hypertension is unrelated to the severity of portal hypertension or the etiology or severe of liver disease. Pulmonary hypertension in patients with liver disease or portal hypertension can be due to multiple mechanisms: hyperdynamic (high-flow) state, increased pulmonary venous congestion (pulmonary venous hypertension), and vascular constriction or obstruction of the pulmonary arterial bed. Vascular obstruction to pulmonary arterial flow, reflected by increased pulmonary vascular resistance, is an important parameter that defines portopulmonary hypertension. Among patients with portal hypertension, reported incidence rates of portopulmonary hypertension range from 2% to 9%. Long-term survival in cases of portopulmonary hypertension is poor. Favorable responses to pulmonary artery hypertension-specific therapy have been observed, but prospective, randomized trials are lacking. Severe portopulmonary hypertension with right ventricular failure despite vasodilator therapy is associated with adverse outcomes in the setting of liver transplantation and is therefore considered a contraindication to liver transplantation unless pulmonary artery hypertension-specific therapy is able to lower the pulmonary vascular resistance to safe levels. The post-liver transplant course of patients with moderate portopulmonary hypertension is unpredictable, but most patients can be weaned from pulmonary artery hypertension-specific therapy over time.