End-stage liver disease has a causal role in 2 main pulmonary syndromes: hepatopulmonary syndrome (HPS) and portopulmonary hypertension (POPH). Hepatopulmonary syndrome is characterized by abnormal intrapulmonary vascular dilation in patients with liver disease, leading to physiologic shunting, ventilation-perfusion mismatch, and hypoxemia (75). Patients with HPS typically have normal or only mildly elevated pulmonary artery pressures, and LT may be curative. POPH is a form of pulmonary arterial hypertension with increased pulmonary vascular resistance due to vasoconstriction and progressive pulmonary vascular remodeling. Patients with this condition by definition have concomitant portal hypertension (75). In POPH, as opposed to HPS, hypoxemia occurs late and LT is often contraindicated if it is left untreated. POPH is present in approximately 5% to 10% of LT candidates (76). Roughly 5% of LT candidates have moderate to severe POPH, with a mean pulmonary arterial pressure (mPAP) ≥35 mm Hg, which has traditionally been considered a contraindication to LT. A pre-operative mPAP of 35 to 50 mm Hg has been associated with a 50% risk of mortality after LT in patients with POPH (77). In 1 study, mortality approached 100% among patients with POPH and mPAP >50 mm Hg (78). The accurate diagnosis of POPH, therefore, is a crucial part of the selection and perioperative management of LT candidates. POPH can present a diagnostic challenge in ESLD; pulmonary artery systolic pressure on TTE may be elevated for many reasons aside from POPH, including pulmonary venous hypertension from left ventricular dysfunction, volume overload, or increased cardiac output.