Review article: Update on current and emergent data on hepatopulmonary syndrome

Abstract

Hepatopulmonary syndrome (HPS) is a frequent pulmonary complication of end-stage liver disease, characterized by impaired arterial oxygenation induced by intrapulmonary vascular dilatation. Its prevalence ranges from 4% to 47% in patients with cirrhosis due to the different diagnostic criteria applied among different studies. Nitric oxide overproduction and angiogenesis seem to be the hallmarks of a complicated pathogenetic mechanism, leading to intrapulmonary shunting and ventilation-perfusion mismatch. A classification of HPS according to the severity of hypoxemia has been suggested. Contrast-enhanced echocardiography represents the gold standard method for the detection of intrapulmonary vascular dilatations which is required, in combination with an elevated alveolar arterial gradient to set the diagnosis. The only effective treatment which can modify the syndrome’s natural history is liver transplantation. Although it is usually asymptomatic, HPS imparts a high risk of pretransplantation mortality, independently of the severity of liver disease, while there is variable data concerning survival rates after liver transplantation. The potential of myocardial involvement in the setting of HPS has also gained increasing interest in recent research. The aim of this review is to critically approach the existing literature of HPS and emphasize unclear points that remain to be unraveled by future research.

Cardiac Imaging in Liver Transplantation Candidates: Current Knowledge and Future Perspectives

“…Orthodeoxia (decrease in oxygen saturation while upright or in siting body position) is a characteristic sign and can be justified by the increased V/Q mismatch. HPS can be detected in about 20% of cirrhotic patients and up to 50% of end-stage patients undergoing LT evaluation but those values differ across the studies [90].…”

Pulmonary manifestations of chronic liver disease: a comprehensive review

“…HPS is characterized by an impairment of arterial oxygenation in the setting of chronic liver disease, PH or congenital portosystemic shunts, as a result of localized or diffuse intrapulmonary vascular dilatations and arteriovenous communications leading to right-to-left intrapulmonary shunt [5,6]. The above elements form the revised diagnostic criteria for HPS, which can be summarized in the triad of chronic liver disease, gas exchange abnormalities, and evidence of intrapulmonary vasodilatation [1] (Table 1).…”

“…More specifically, patients with a mean PAP of 35-45 mmHg and a PVR >240 dyn·sec·cm -5 should receive vasodilator therapy before transplantation and patients with mean PAP >45 mmHg should receive vasodilator therapy only. Those patients with a good clinical response to treatment achieving a mean PAP <35 mmHg should undergo LT [5]. Moreover, LT should be considered when mean PAP cannot be reduced below 35 mmHg but there is normalization of PVR (<240 dyn·sec·cm -5 ) [5].…”

“…Those patients with a good clinical response to treatment achieving a mean PAP <35 mmHg should undergo LT [5]. Moreover, LT should be considered when mean PAP cannot be reduced below 35 mmHg but there is normalization of PVR (<240 dyn·sec·cm -5 ) [5]. Note that a mean PAP greater than 50 mmHg constitutes an absolute contraindication for LT, regardless of therapy.…”

Pulmonary Complications in Candidates for Liver Transplantation

“…Hepatopulmonary syndrome (HPS) is defined by portal hypertension with or without concomitant liver cirrhosis, pulmonary gas exchange abnormalities, and arterial hypoxemia caused by intrapulmonary vascular dilatations. [30][31][32][33][34] (Figure 1). Approximately, 4-47% of patients with documented liver cirrhosis and 4-32% of candidates for LT are diagnosed with HPS.…”