Hepatopulmonary syndrome: An update

An Update on IL-22 Therapies in Alcohol-Associated Liver Disease and Beyond

Excessive alcohol consumption drives the development of alcohol-associated liver disease (ALD), including steatohepatitis, cirrhosis, and hepatocellular carcinoma, and its associated complications, such as hepatorenal syndrome. Hepatocyte death, inflammation, and impaired liver regeneration are key processes implicated in the pathogenesis and progression of ALD. Despite extensive research, therapeutic options for ALD remain limited. IL-22 has emerged as a promising therapeutic target because of its hepatoprotective properties mediated through the activation of the STAT3 signaling pathway. IL-22 enhances hepatocyte survival by mitigating apoptosis, oxidative stress, and inflammation while simultaneously promoting liver regeneration through the proliferation of hepatocytes and hepatic progenitor cells and the up-regulation of growth factors. Additionally, IL-22 exerts protective effects on epithelial cells in various organs affected by ALD and its associated complications. Studies from preclinical models and early-phase clinical trials of IL-22 agonists, such as F-652 and UTTR1147A, have shown favorable safety profiles, good tolerability, and encouraging efficacy in reducing liver injury and promoting regeneration. However, the heterogeneity and multifactorial nature of ALD present ongoing challenges. Further research is needed to optimize IL-22-based therapies and clarify their roles within a comprehensive approach to ALD management. This review summarizes the current understanding of IL-22 biology and its role in ALD pathophysiology and ALD-associated complications along with therapeutic application of IL-22, potential benefits, and limitations.

High-Flow Oxygen Therapy to Support Inpatient Pulmonary Rehabilitation During Very Severe Hepatopulmonary Syndrome Recovery Post Liver Transplant: A Case Report

This case study reports the novel use of inpatient pulmonary rehabilitation (PR) with near-maximal high-flow oxygen therapy in a patient recovering from very severe hepatopulmonary syndrome (HPS) following liver transplantation. HPS is a rare condition where advanced liver disease alters lung microvasculature through intrapulmonary vascular dilatation (IPVD) and angiogenesis. Platypnoea-orthodeoxia (postural dyspnoea with concurrent blood oxygen desaturation) is characteristic of HPS due to redirection of blood flow to the basal lung where IPVDs are more prominent, secondary to gravity. Currently, the only definitive treatment is liver transplantation, which allows normalization of oxygenation over an extended period, typically within 1 year. Pulmonary rehabilitation is an effective intervention for improving dyspnoea, health-related quality of life (HRQoL), and exercise capacity in people with chronic respiratory disease. Despite this, little is known of the effect PR has on individuals recovering from HPS post liver transplant. The aim is to describe an inpatient PR program for a patient recovering from HPS. This case study describes a 27-year-old male with "very severe" HPS who undertook inpatient PR 5 months posttransplant. The patient completed an 8-week program of twice-weekly PR supported by high-flow oxygen therapy (fraction of inspired oxygen of 90%). He performed aerobic and resistance exercises for the upper and lower limbs in recumbent, seated, and standing positions. The patient improved in exercise capacity on the 1-min sit-to-stand test (+4 repetitions), lower limb strength on the 5-repetition sit-to-stand test (-3.4 s) and in HRQoL outcomes assessed. Following rehabilitation, the patient still had a high burden of respiratory symptoms and required continuous high-flow oxygen therapy. This case study demonstrates that inpatient PR, modified for HPS-associated platypnoea-orthodeoxia and supported by high-flow oxygen therapy, is safe and effective and therefore feasible for other HPS patients.

Timing and Indications for Liver Transplantation for Children with Chronic Liver Disease

Chronic liver disease (CLD) in children poses significant challenges, necessitating timely management to mitigate morbidity and mortality. Liver transplantation (LT) has emerged as a transformative intervention, offering improved long-term survival for paediatric patients with CLD. This review explores the evolving landscape of liver transplantation, focusing on indications and timing considerations. The aetiology of CLD is diverse, encompassing intrahepatic, extrahepatic cholestatic conditions, metabolic diseases, malignancy, and drug-induced liver injury. LT is indicated when children exhibit signs of hepatic decompensation, necessitating a comprehensive evaluation to assess transplant suitability. Indications for LT include biliary atresia, inborn errors of metabolism, hepatocellular carcinoma, and emerging indications such as mitochondrial hepatopathies and acute on chronic liver failure. The timing of transplantation is critical, emphasizing the need for early recognition of decompensation signs to optimise outcomes. Advancements in LT techniques and immunosuppressive therapies have enhanced patient and graft survival rates. Various transplant modalities, including reduced-size LT and living-related LT, offer tailored solutions to address the unique needs of paediatric patients. While LT represents a cornerstone in the management of paediatric CLD, careful patient selection, multidisciplinary collaboration, and ongoing refinements in transplant protocols are imperative for optimizing outcomes and addressing the evolving landscape of paediatric liver disease management.

Echocardiographic evaluation in patient candidate for liver transplant: from pathophysiology to hemodynamic optimization

Cardiovascular complications are common in patients with severe liver disease and are an important cause of peri-operative and post-transplant morbidity and mortality. Cirrhotic cardiomyopathy (CCM), often found in advanced liver disease, is characterized by diastolic dysfunction, systolic dysfunction, and electrophysiological abnormalities. While CCM may not cause symptoms at rest, it can become evident during stressful activities, such as surgery. Liver transplantation, while being the definitive treatment for end-stage liver disease (ESLD), carries significant cardiovascular risks. Preoperative cardiac evaluation is essential for assessing these risks and planning appropriate management. Cardiac imaging, particularly echocardiography, plays a crucial role in evaluating liver transplant candidates, helping to identify conditions such as CCM, pulmonary hypertension, hepatopulmonary syndrome, and others. Currently, liver transplant anesthetists must acquire echocardiographic knowledge and skills to evaluate the cardiocirculatory conditions of the transplanted patient, especially in the pre-operative phase, but also intra-operatively and post-operatively.

Hepatopulmonary syndrome secondary to metabolic associated fatty liver disease in childhood - novel treatment with growth hormone replacement therapy: a case report and systematic review of literature

Objective

Hepatopulmonary syndrome (HPS) is a rare complication of metabolic associated fatty liver disease (MAFLD) occurring subsequent to hypopituitarism, often developing after resection of hypothalamic or pituitary tumors. The aim of this study is to report an illustrative case of an HPS patient who was successfully treated with growth hormone replacement therapy, without liver transplantation which is conventionally regarded as the only treatment option. Additionally, we conducted a comprehensive review of published case reports of HPS in the pediatric population.

Methods

We systematically searched literature databases to identify case reports and case series of HPS associated with hypopituitarism diagnosed in childhood. The search included MEDLINE/PubMed, Scopus, Embase, and Google Scholar from 1990 to 2023. The review process adhered to the PRISMA checklist for comprehensive reporting and methodological transparency.

Results

An 18-year-old female, who had been followed up for MAFLD after craniopharyngioma resection, presented with cyanosis and progressive dyspnea. She was diagnosed with severe degree of HPS. The patient began treatment with recombinant human growth hormone, leading to a significant improvement in respiratory symptoms within 3 months, and normalization of lung shunt ratio after 6 months of therapy. In our systematic review, nine patients from nine studies across six countries were identified. The median age at diagnosis of hypopituitarism was 10.5 years (range 1-16 years), and HPS was diagnosed at a median interval of 7 years later (range 0-26 years). Half of the patients had not received growth hormone therapy after being diagnosed with hypopituitarism, which subsequently led to the diagnosis of HPS. Three patients underwent liver transplantation, but non-alcoholic steatohepatitis recurred in all cases. Six patients were successfully treated with growth hormone replacement therapy without undergoing liver transplantation.

Conclusions

HPS can occur in pediatric patients with MAFLD who have undergone resection of the tumor in the hypothalamus or pituitary gland. Our findings suggest that growth hormone replacement therapy can be a possible alternative to liver transplantation for HPS patients. However, further investigations need to be performed to validate the efficacy of growth hormone treatment in different causes of HPS cases.

Effects of Transjugular Intrahepatic Portosystemic Shunt on Renal and Pulmonary Function in Hepatic Decompensation with and without Hepatorenal and Hepatopulmonary Syndromes: A Review

Cirrhosis is often characterized by decreased liver function, ranging from a compensated, typically asymptomatic phase to a decompensated phase characterized by the appearance of ascites or variceal bleeding, and ultimately hepatorenal syndrome (HRS) or hepatopulmonary syndrome (HPS). The latter two complications are associated with a poor prognosis and limited treatment efficacy. In cases of ascites or variceal bleeding resistant to medical therapy, transjugular intrahepatic portosystemic shunt (TIPS) is effective and safe. Shunting blood by TIPS diverts portal blood to the systemic circulation, potentially increasing systemic blood volume and benefiting renal function. However, TIPS could also divert nitric oxide to the systemic circulation, potentially worsening systemic hypotension and perfusion, which could be detrimental to renal function. Available evidence indicates that TIPS often improves renal function in patients with portal hypertension, with or without HRS. No studies have shown persistently decreased renal function after TIPS. However, these data are insufficient to support a recommendation for the use of TIPS specifically for HRS. In patients without pre-existing HPS, TIPS does not appear to significantly affect pulmonary gas exchange. Results of TIPS in HPS have been inconsistent; some studies have shown improvement, but effects were transient. No studies have shown a persistent decline in pulmonary function after TIPS. The evidence supports the need for large randomized controlled trials to investigate the beneficial effects of TIPS for HRS. Similar pulmonary function data are less clear regarding TIPS for HPS. The aim of the current report was to review the literature regarding the effects of TIPS on renal and pulmonary function in hepatic decompensation, with or without the development of HRS or HPS.

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.

Spleen derived monocytes regulate pulmonary vascular permeability in Hepatopulmonary syndrome through the OSM-FGF/FGFR1 signaling

Hepatopulmonary syndrome (HPS) is a serious pulmonary complication in the advanced stage of liver disease. The occurrence of pulmonary edema in HPS patients is life-threatening. Increased pulmonary vascular permeability is an important mechanism leading to pulmonary edema, and endothelial glycocalyx (EG) is a barrier that maintains stable vascular permeability. However, in HPS, whether the pulmonary vascular EG changes and its regulatory mechanism are still unclear. Spleen derived monocytes are involved in the pathogenesis of HPS. However, whether they regulate the pulmonary vascular permeability in HPS patients or rats and what is the mechanism is still unclear. Healthy volunteers and HPS patients with splenectomy or not were enrolled in this study. We found that the respiration of HPS patients was significantly improved in response to splenectomy, while the EG degradation and pulmonary edema were aggravated. In addition, HPS patients expressed higher levels of oncostatin M (OSM) and fibroblast growth factor (FGF). Subsequently, the co-culture system of monocytes and human umbilical vein endothelial cells (HUVECs) was constructed. It was found that monocytes secreted OSM and activated the FGF/FGFR1 signaling pathway in HUVECs. Then, an HPS rat model was constructed by common bile duct ligation (CBDL) for in vivo verification. HPS rats were intravenously injected with OSM recombinant protein and/or TNF-α into the rats via tail vein 30 min before CBDL. The results showed that the respiration of HPS rats was improved after splenectomy, while the degradation of EG in pulmonary vessels and vascular permeability were increased, and pulmonary edema was aggravated. Moreover, the expression of OSM and FGF was upregulated in HPS rats, while both were downregulated after splenectomy. Intravenous injection of exogenous OSM eliminated the effect of splenectomy on FGF and improved EG degradation. It can be seen that during HPS, spleen-derived monocytes secrete OSM to promote pulmonary vascular EG remodeling by activating the FGF/FGFR1 pathway, thereby maintaining stable vascular permeability, and diminishing pulmonary edema. This study provides a promising therapeutic target for the treatment of HPS.

Diagnostic Potential of 99mTc-macroaggregated Albumin Scintigraphy in the Diagnosis of Hepatopulmonary Syndrome: Insights from Two Case Studies and Critical Review of Literature

Hepatopulmonary syndrome (HPS) is a rare pulmonary vascular complication of chronic liver disease characterized by dilatation of pulmonary capillaries leading to vascular shunting and systemic hypoxemia. Diagnosis of HPS requires documentation of intrapulmonary vasodilation (IPVD), the two most common imaging studies performed for the detection of IPVD include transthoracic contrast echocardiography (TTCE) and 99m-Tc-macroaggregated albumin scintigraphy (99mTc-MAA scan). TTCE has high sensitivity and thus, is the preferred initial investigation, while 99mTc-MAA scan is highly specific and plays an adjuvant role in diagnosis. 99mTc-MAA scan can, however, identify some cases of HPS not apparent on TTCE and can also quantify the shunt fraction. The current study describes the utility of 99mTc-MAA scan in the detection of IPVD in two suspected cases of HPS.

Planned Venovenous-Extracorporeal Membrane Oxygenation as a Bridge to Orthotopic Liver Transplant Performed for Very Severe Hepatopulmonary Syndrome: A Case Report

Concerns related to poor oxygenation in patients with severe hepatopulmonary syndrome (HPS) may be prohibitive when considering their candidacy for liver transplantation. Extracorporeal membrane oxygenation (ECMO) has been utilized in only a few case reports as a bridge to liver transplant in patients with severe respiratory failure. We report a case of a 66-year-old man with cirrhosis and very severe (arterial oxygen pressure (PaO2) < 50 mmHg) hepatopulmonary syndrome who underwent an orthotopic liver transplant with the planned use of venovenous-ECMO. Pre-transplant echocardiography demonstrated a small-trivial patent foramen ovale (PFO) but following the resolution of hepatopulmonary shunting after liver transplantation, the PFO size enlarged and contributed to a thromboembolic stroke. We conclude that well-selected patients with HPS could benefit from the use of planned venovenous-ECMO and that a small-trivial PFO seen in a patient with HPS may warrant intervention prior to transplantation.

Pathophysiological basis of hepatopulmonary syndrome

Circulatory changes with increased blood flow and vasodilatation/vasoconstriction imbalance are an integral consequence of liver cirrhosis and portal hypertension and can affect the pulmonary circulation with the development of vascular disorders, with hepatopulmonary syndrome (HPS) being the most common. HPS is a serious pulmonary complication of progressive liver disease, resulting in a poor clinical prognosis. Vascular tone decrease, monocytic infiltration of pulmonary vessels, formation of intrapulmonary arteriovenous shunts, dysfunction of alveolar type II cells, destruction of the endothelial glycocalyx are important in the pathogenesis of HPS. Abnormalities of pulmonary capillaries lead to hypoxemia caused by a violation of the ventilation/perfusion ratio, diffusion disorders, and the development of arteriovenous anastomoses. Infiltration of the pulmonary vessels by monocytes is one of the key factors of HPS. This migration is facilitated by the intestinal microbiota translocation into the portal bloodstream with increased expression of proinflammatory cytokines (tumor necrosis factor α, interleu­kins 1, 6), leading to the activation of monocytes. Monocytes located in the pulmonary circulation promote the vasodilation through the activation of inducible nitric oxide (NO) synthase and thus NO production. This is also associated with endothelial dysfunction due to a decreased hepatic secretion of bone morphogenetic protein 9 and increased endothelin 1, endothelial overexpression of endothelin B receptors, and increased endothelial NO production. Proangiogenic factors such as vascular endothelial growth factor, platelet-derived growth factor, and placental growth factor play an important role in the proliferation of pulmonary capillaries. Circulation of tumor necrosis factor α, bile acids and monocyte infiltration in the pulmonary circulation lead to increased apoptosis of alveolar type II cells and decreased surfactant synthesis. Chronic inflammation in HPS disrupts the continuity of the endothelial glycocalyx layer. This article provides an overview of the current knowledge on the pathogenesis of HPS, summarizes many features of the disease based on the literature research in MEDLINE database on the PubMed platform.

Hepatopulmonary Syndrome Diagnosis in the ICU: The Relevance of Bedside Contrast Saline Echocardiography

Hepatopulmonary syndrome (HPS) is an underdiagnosed complication of chronic liver disease (CLD) characterised by the presence of hypoxaemia due to intrapulmonary vascular dilatations. We present two cases of HPS diagnosed during their stay in the ICU. Both patients had a medical history of alcoholic CLD with portal hypertension (PH). The first patient was transferred to the ICU for acute hypoxic respiratory failure (AHRF) due to decompensated cirrhosis with large-volume hydrothorax and diagnosis of acute-on-chronic liver failure (ACLF) grade 2. The presence of orthodeoxia, an alveolar-arterial oxygen gradient (O2 A-a grad) of 27 mmHg and positive contrast saline echocardiography confirmed the HPS diagnosis. The second patient was transferred to our general ICU from the surgical ward where he was initially admitted with mild AHRF due to polytrauma conditioning left side rib fractures and a small contusion in the left inferior lobe. Upon ICU admission, he was diagnosed with septic shock (nosocomial pneumonia as the primary site of infection) and required invasive mechanical ventilation. During the initial period of his ICU stay, although an improvement in multiple organ dysfunction was observed, severe AHRF persisted. Moreover, O2 A-a grad of 30 mmHg and positive bedside contrast saline echocardiography confirmed the HPS diagnosis. In this study, we discuss the diagnostic approach of HPS and the increasing relevance of contrast saline echocardiography at the bedside, particularly in critically ill patients. The performance of this technique by trained intensivists at the bedside in the ICU minimises critical moments, such as the time required for intra-hospital transport of patients for complementary examinations, considering they have severe ventilatory compromise, thereby allowing HPS diagnosis with high sensitivity.

Hepatopulmonary Syndrome in a Patient With Autoimmune Hepatitis and Chronic Hepatitis C: A Case Report Highlighting Typical Echo Findings

Hepatopulmonary syndrome (HPS) is a rare complication of liver disease characterized by intrapulmonary vascular dilatations leading to arterial hypoxemia. We present the case of a 59-year-old female with a past medical history of bilateral breast cancer status post mastectomy who presented with progressive dyspnea on exertion and fatigue. A comprehensive diagnostic workup was conducted to exclude other cardiac, pulmonary, and systemic etiologies. She was diagnosed with autoimmune hepatitis along with chronic hepatitis C. Echocardiography revealed characteristic findings of intrapulmonary shunting characteristic of HPS. The patient showed improvement in pulmonary symptoms and oxygenation status following the initiation of steroid therapy. Although corticosteroids are not the definitive treatment for HPS, they were considered a supportive measure in this case. However, it is important to note that liver transplantation remains the definitive treatment for HPS. This case underscores the importance of echocardiography and the potential role of supportive measures, like corticosteroids, in managing HPS-related symptoms, particularly in patients with autoimmune hepatitis, as a bridging therapy while awaiting liver transplantation.