Technetium-99m-labeled macroaggregated albumin lung perfusion scan for diagnosis of hepatopulmonary syndrome: A prospective study comparing brain uptake and whole-body uptake

HEPATOPULMONARY SYNDROME IN PEDIATRIC PATIENTS WITH PORTAL HYPERTENSION - AN INTEGRATIVE REVIEW

BACKGROUND

Hepatopulmonary syndrome (HPS) is characterized by the triad of abnormal arterial oxygenation caused by intrapulmonary vascular dilatations (IPVD) in the setting of advanced liver disease or portal hypertension, impacting the patient's quality of life and survival. There are still many gaps in the literature on this topic, especially in pediatrics, with practices frequently based on extrapolation of data obtained from adults.

OBJECTIVE

Provide a synthesis of the current knowledge about HPS in children.

METHODS

The research was carried out through narrative review. The databases used for the search include Medline, Embase, Elsevier, Lilacs and Scielo. The keywords used were "hepatopulmonary syndrome" AND child, children, infant, preschool, pediatric.

RESULTS

In cirrhotic children, the prevalence of HPS can reach up to 42.5%, and it is even more common in those whose underlying condition is biliary atresia, reaching up to 63%. Screening with pulse oximetry (O2 saturation <96%), unlike in adults, has low sensitivity in the pediatric age group. Management involves supportive care with oxygen therapy; liver transplantation is the only definitive treatment to reverse the condition and HPS is considered an exceptional criterion for waitlist. The waitlist mortality is similar among children listed by HPS as a special criterion when compared to those listed for other reasons. The reported rates of complete resolution of hypo-xemia after liver transplantation are close to 100% in children. The post-liver transplantation survival is similar or slightly lower in children with HPS when compared to those without HPS. Contrary to findings from adults, no differences were found in post- liver transplantation mortality between children of different hypoxemia ranges, although longer mechanical ventilation time and hospital stay were observed in children with PaO2 <50 mmHg.

CONCLUSION

HPS is not an uncommon complication of cirrhosis in children and adolescents, particularly when biliary atresia is the underlying condition. There are still many gaps to be filled regarding the condition, and this article demonstrates that not all data obtained in studies with adults reflects the disease's behavior in pediatrics, especially concerning prognosis.

Hepatopulmonary syndrome: diagnosis and treatment

Hepatopulmonary syndrome (HPS) is one of the lung diseases associated with liver cirrhosis and portal hypertension. The diagnosis is based on the triad: liver disease and portal hypertension, evidence of intrapulmonary vascular dilatation and impaired gas exchange. HPS impairs prognosis (23 % survival after 5 years) and patients’ quality of life, so early diagnosis and timely treatment are of great importance. Liver transplantation allows for regression of intrapulmonary vascular dilatation in almost 100 % of cases, normalization of gas exchange and improves a 5-year survival after transplantation from 76 to 87 %. This is the only treatment method indicated for patients with severe HPS, defined by an arterial partial pressure of oxygen (PaO2) below 60 mm Hg. However, in the face of a global shortage of transplants, it is necessary to develop medical therapies to delay or even defer liver transplantation. This goal seems possible due to the growing understanding of the HPS pathophysiology and the development of therapies targeting key mechanisms, mainly inflammatory and angiogenic. This article provides an overview of the clinical manifestations, diagnosis and treatment of HPS based on literature sources from the MEDLINE database on the PubMed platform.

Imaging in hepatopulmonary syndrome-case report. A multicenter approach during the coronavirus pandemic

A 60-year-old lady with alcoholic liver disease developed central cyanosis and orthodeoxia. A technetium-99m macro-aggregated albumin lung perfusion scan and contrast echocardiogram were performed. A 13% right to left shunt was calculated from the macro-aggregated albumin scan. There were more bubbles in the left heart than the right at the end of the contrast echocardiogram. Hepatopulmonary syndrome was therefore diagnosed. The patient had a liver transplant five days after these investigations. Further discussion about hepatopulmonary syndrome will be provided. Normally, macro-aggregated albumin scans are performed in few centers, however as this was at the height of the coronavirus pandemic, the scan needed to be performed locally to reduce the chance of the patient getting coronavirus. Local radiographers were remotely instructed on conducting the macro-aggregated albumin scan by a larger center to provide a timely and important investigation in a logistically difficult scenario.

Prevalence and prognostic impact of hepatopulmonary syndrome in patients with unresectable hepatocellular carcinoma undergoing transarterial chemoembolization: a prospective cohort study

BACKGROUND

To determine the prevalence and prognostic impact of hepatopulmonary syndrome (HPS) in patients with unresectable hepatocellular carcinoma (HCC) undergoing transarterial chemoembolization (TACE).

METHODS

Fifty-four patients with unresectable HCC undergoing TACE between December 2014 and December 2015 were prospectively screened for HPS and were followed up for a maximum of 2 years or until the end of this prospective study.

RESULTS

Nineteen of the 54 (35.2%) patients were considered to have HPS, including one (5.3%) with severe HPS, nine (47.4%) with moderate HPS, and nine (47.4%) with mild HPS. The median overall survival (OS) was 10.1 (95% confidence interval [CI], 3.9-16.3) months for patients with HPS and 15.1 (95% CI, 7.3-22.9) months for patients without HPS, which is not a significant difference ( P  = 0.100). The median progression-free survival was also not significantly different between patients with and without HPS (5.2 [95% CI, 0-12.8] vs. 8.4 [95% CI, 3.6-13.1] months; P  = 0.537). In the multivariable Cox regression analyses, carbon monoxide diffusing capacity (hazard ratio [HR] = 1.033 [95% CI, 1.003-1.064]; P  = 0.028) and Child-Pugh class (HR = 1.815 [95% CI, 1.011-3.260]; P  = 0.046) were identified to be the independent prognostic factors of OS.

CONCLUSION

Mild or moderate HPS is common in patients with unresectable HCC undergoing TACE, but it does not seem to have a significant prognostic impact.

Evaluation of Hepatopulmonary Syndrome with Technetium-99m Macroaggregated Albumin Scintigraphy

Hepatopulmonary syndrome (HPS) is characterized by intrapulmonary vascular dilatation causing hypoxemia in patients with liver disease. Technetium-99m macroaggregated albumin (99mTc-MAA) scintigraphy have diagnostic value in suspected HPS by detecting clinically significant right to left shunt. In presence of cirrhosis, MAA scan with extra-pulmonary organs visualization is specific of intrapulmonary shunting. MAA scintigraphy also provides added value of quantification of the shunt.

Advances in Diagnostic Imaging of Hepatopulmonary Syndrome

Hepatopulmonary syndrome (HPS) is a serious pulmonary complication of progressive liver disease that leads to a poor clinical prognosis. Patients with HPS may develop acute respiratory failure, which requires intensive care and therapy. At present, the only effective treatment is liver transplantation; therefore, early diagnosis and timely treatment are of considerable significance. The three main features of HPS are liver disease, oxygenation disorder, and intrapulmonary vascular dilatation (IPVD). Diagnosing HPS is challenging due to the difficulty in detecting the presence or absence of IPVD. As such, imaging examination is very important for detecting IPVD. This paper reviews the imaging methods for diagnosing HPS such as ultrasound, dynamic pulmonary perfusion imaging, pulmonary angiography, and computed tomography.

Hepatopulmonary Syndrome and Portopulmonary Hypertension: Pulmonary Vascular Complications of Liver Disease

Pulmonary vascular disease is a frequent complication of chronic liver disease and portal hypertension, affecting up to 30% of patients. There are two distinct pulmonary vascular complications of liver disease: hepatopulmonary syndrome (HPS) and portopulmonary hypertension (POPH). HPS affects 25% of patients with chronic liver disease and is characterized by intrapulmonary vasodilatation and abnormal arterial oxygenation. HPS negatively impacts quality of life and is associated with a 2-fold increased risk of death compared to controls with liver disease without HPS. Angiogenesis, endothelin-1 mediated endothelial dysfunction, monocyte influx, and alveolar type 2 cell dysfunction seem to play important roles in disease pathogenesis but there are currently no effective medical therapies. Fortunately, HPS resolves following liver transplant (LT) with improvements in hypoxemia. POPH is a subtype of pulmonary arterial hypertension (PAH) characterized by an elevated mean pulmonary arterial pressure and pulmonary vascular resistance in the setting of normal left-sided filling pressures. POPH affects 5% to 6% of patients with chronic liver disease. Although the pathogenesis has not been fully elucidated, endothelial dysfunction, inflammation, and estrogen signaling have been identified as key pathways involved in disease pathogenesis. POPH is typically treated with PAH targeted therapy and may also improve with liver transplantation in selected patients. This article highlights what is currently known regarding the diagnosis, management, pathobiology, and outcomes of HPS and POPH. Ongoing research is needed to improve understanding of the pathophysiology and outcomes of these distinct and often misunderstood pulmonary vascular complications of liver disease. © 2021 American Physiological Society. Compr Physiol 11:1-22, 2021.

Analogies and differences between cirrhotic cardiomyopathy and hepatopulmonary syndrome

Cirrhotic cardiomyopathy and hepatopulmonary syndrome are two quite frequent clinical entities that may complicate the course of liver cirrhosis. The common pathophysiological origin and the same clinical presentation make them difficult to compare. Cirrhotic cardiomyopathy and hepatopulmonary syndrome may start with dyspnea and breathlessness but the former is characterized by a chronic cardiac dysfunction and the latter by a defect of oxygenation due to pulmonary shunts formation. The focus is to differentiate them as soon as possible since the treatment is different until the patient undergoes liver transplant that is the real unique cure for them.