A 70-year-old man with hepatitis B-associated cirrhosis and hepatocellular carcinoma presented with a two-week history of shortness of breath. He was also experiencing ongoing fatigue, anorexia, edema and exertional dyspnea, which had begun two months earlier after transcatheter arterial chemoembolization. His partial pressure of oxygen was 67 mm Hg, and the alveolar–arterial gradient was elevated at 43 mm Hg when he breathed room air in a supine position. His oxygen saturation decreased from 96% to 91% when he sat upright from a recumbent position. Chest radiography showed increased, diffuse interstitial markings (Appendix 1, at www.cmaj.ca/cgi/content/full/cmaj.090576/DC1). Contrast echocardiography showed enhancement in the left heart five beats after microbubbles opacified the right heart (Figure 1). Hepatopulmonary syndrome was diagnosed and was managed with oxygen, bed rest, salt restriction and diuretics.
Hepatopulmonary syndrome is characterized by intrapulmonary vascular dilatations and shunting, which lead to arterial deoxygenation in patients with advanced liver disease.1 The prevalence of the syndrome among such patients ranges from 13% to 47%.2 Orthodeoxia–platypnea, defined as a decrease in the partial pressure of oxygen of at least 5% or at least 4 mm Hg in an upright position, is highly specific for hepatopulmonary syndrome.1,3,4 The mortality associated with hepatopulmonary syndrome is high, with a median survival of 10.6 months.2 The only definitive treatment is liver transplantation, for which a five-year survival rate of 76% has been reported.4
A definite diagnosis of hepatopulmonary syndrome requires scintigraphy with technetium-99m-labelled macroaggregated albumin, pulmonary angiography or contrast echocardiography. Contrast echocardiography is more sensitive and less invasive than angiography,1 but the latter may be considered when direct arteriovenous communication is strongly suspected. In hepatopulmonary syndrome, the microbubbles during contrast echocardiography pass through the abnormally dilated pulmonary vasculature into the left heart with a delay of three to six heart beats. In an intracardiac shunt, enhancement appears in the left heart within the first three cardiac cycles.5
Footnotes
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See related article by Lin and colleagues, page 77
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This article has been peer reviewed.
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Competing interests: None declared.
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See videos online of the contrast echocardiography: www.cmaj.ca/cgi/content/full/cmaj.090576/DC1