Portopulmonary hypertension is pulmonary arterial hypertension associated with portal hypertension without other secondary causes.
Pulmonary hypertension occurs in patients with various conditions that lead to portal hypertension with or without cirrhosis. Portopulmonary hypertension develops in 2 to 6% of patients with portal hypertension (1).
Abnormalities in bone morphogenetic protein 9 (BMP9) signaling are linked to the development of pulmonary hypertension. BMP9 and BMP10 are produced in the liver and are ligands for the BMP2 receptor. Patients with portopulmonary hypertension have been noted to have a significantly reduced BMP9 level when compared to control patients with advanced liver disease. There was no difference in BMP10 levels when comparing patients with portopulmonary hypertension to patients with advanced liver disease without portopulmonary hypertension (2).
Presenting symptoms are dyspnea and fatigue. Chest pain and hemoptysis can also occur. Patients have physical findings and ECG abnormalities consistent with pulmonary hypertension and may develop evidence of cor pulmonale (elevated jugular venous pulse, edema). Tricuspid regurgitation is common.
The diagnosis is suspected based on echocardiography findings and confirmed by right heart catheterization.
Treatment of portopulmonary hypertension is the same as that of pulmonary arterial hypertension except that hepatotoxic medications and anticoagulants should be avoided. Beta-blockers, frequently used in portal hypertension, should also be avoided in portopulmonary hypertension due to hemodynamic instability (1). Some patients benefit from vasodilator therapy.
The underlying liver disease is a major determinant of outcome. Poorly controlled portopulmonary hypertension is a relative contraindication to liver transplantation because of increased morbidity and mortality from the procedure. However, in some patients who receive a transplant, particularly those with mild pulmonary hypertension, pulmonary hypertension regresses. Some centers consider transplantation in patients who have mean pulmonary arterial pressures < 35 mm Hg after a trial of vasodilator therapy.
References
1. Humbert M, Kovacs G, Hoeper MM, et al: 2022 ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension. Eur Respir J 61(1):2200879, 2023. doi:10.1183/13993003.00879-2022
2. Rochon ER, Krowka MJ, Bartolome S, et al: BMP 9/10 in pulmonary vascular complications of liver disease. Am J Respir Crit Care Med 201 (11):1575–1578, 2020. doi: 10.1164/rccm.201912-2514LE
