Portopulmonary hypertension

Portopulmonary hypertension (POPH) is a serious complication of portal hypertension that is associated with significant mortality. It is defined as the presence of pulmonary arterial hypertension in patients with documented portal hypertension. While pulmonary hypertension in liver disease can be due to a hyperdynamic (high-flow) state or increased pulmonary venous congestion (pulmonary venous hypertension), POPH develops because of vascular constriction or obstruction of the pulmonary arterial bed, manifesting as increased pulmonary vascular resistance. The reported incidence rates of POPH among liver transplant (LT) candidates range from 4.5 to 8.5 %. The severity of this condition is unrelated to the degree of portal hypertension or the etiology of liver disease. Intraoperative death and immediate post-LT mortality have occurred when LT is attempted in the setting of untreated, moderate-to-severe POPH. Transplantation is contraindicated unless the mean pulmonary artery pressure can be reduced to a safe level and right ventricular function is optimized. Screening for and accurately diagnosing POPH prior to LT has become the standard of care. Specific pulmonary artery vasodilator medications appear effective in reducing pulmonary artery pressures, improving right ventricular function and survival in uncontrolled studies from patients with POPH. The post-LT course of patients with moderate-to-severe POPH is unpredictable, but many patients can be weaned from pulmonary artery vasodilatory therapy over time.