Pulmonary Manifestations of Cirrhosis: A Narrative Review of Hepatopulmonary and Portopulmonary Syndrome

Pulmonary vascular complications are an important but often underrecognized consequence of cirrhosis and portal hypertension. Two mechanistically distinct syndromes arise from this shared hepatic substrate: hepatopulmonary syndrome (HPS), driven by intrapulmonary vascular dilation and shunting, and portopulmonary hypertension (PoPH), characterized by vasoconstriction and progressive vascular remodeling. HPS affects up to 30% of cirrhotic patients and produces hypoxemia through ventilation-perfusion mismatch and right-to-left shunting, while PoPH develops in 2% - 6% of patients with portal hypertension and accounts for 5% - 15% pulmonary arterial hypertension cases. No established medical therapy alters the natural history of HPS, whereas PAH-targeted agents particularly endothelin receptor antagonists, prostacyclin analogs, and phosphodiesterase-5 inhibitors, can improve hemodynamics in PoPH and serve as a bridge to transplantation. Liver transplantation remains the only curative treatment for HPS and offers significant survival benefit in selected PoPH patients who achieve adequate hemodynamic response to medical therapy. This narrative review synthesizes current evidence on the pathophysiology, diagnosis, medical management, and transplant outcomes for both conditions.