Table 1.
Difference between HPS and PPHTN modified from Rodríguez-Roisin et al[4]
| HPS | PPHTN | |
| Prevalence | 11%-32% of patients with liver cirrhosis | 2% of patients with portal hypertension |
| Pathogenesis | Increased intrapulmonary shunting | Unknown |
| Intrapulmonary vascular dilatations | (+) | (-) |
| Pulmonary arterial hypertension | (-) | (+) |
| Symptom | Dyspnea, platypnea | Dyspnea on exertion, syncope, chest pain |
| Clinical manifestations | Cyanosis | No cyanosis |
| Orthodeoxia | Accentuated pulmonary component of IIs | |
| Spider nevi | Systolic murmur, edema | |
| ECG findings | None | RVH, RBBB, right axis deviation |
| Arterial blood gas levels | Moderate-to-severe hypoxemia (< 60-80 mmHg) | No/mild hypoxemia |
| Chest radiography | Normal | Cardiomegaly, hilar enlargement |
| CEE | Positive finding; left atrial opacification for > 3-6 heart beats after right atrial opacification | Usually negative finding |
| 99mTcMAA shunting index | ≥ 6% | < 6% |
| Pulmonary hemodynamics | Normal/low PVR | Elevated PVR mPAP > 25 mmHg at rest or > 30 mmHg with exercise |
| OLT | Indicated in severe stages | Only indicated in mild-to-moderate stages |
HPS: Hepatopulmonary syndrome; PPHTN: Portopulmonary hypertension; RVH: Right ventricle hypertrophy; IIs: Second heart sound; ECG: Electrocardiography; RBBB: Right bundle-branch block; AaPO2: Alveolar arterial oxygen gradient; CEE: Contrast-enhanced echocardiography;
99m
TcMAA: Technetium-99m-labelled macroaggregated albumin; PVR: Pulmonary vascular resistance; mPAP: Mean pulmonary artery pressure; OLT: Orthotopic liver transplantation.