Impact of hepatopulmonary syndrome on quality of life and survival in liver transplant candidates

Modulating respiratory mechanics and inflammation in hepatopulmonary syndrome: Aerobic exercise as a therapeutic strategy

INTRODUCTION

Aerobic exercise training positively modulates the immune system and improves lung function; however, its effects on respiratory system's elastic, resistive properties and interleukin-10 (IL-10) concentration in hepatopulmonary syndrome (HPS) remains unexplored. This study aimed to assess whether moderate-intensity aerobic (AE) training altered exercise capacity, respiratory mechanics and lung inflammation.

MATERIAL AND METHODS

Wistar rats were randomly assigned to SHAM, HPS, HPS + AE4, and HPS + EA8 groups. The EA4 group represents AE training for 4 weeks starting 7 days after HPS induction, whereas EA8 accounts for AE training for 4 weeks before and after HPS induction, both protocols practiced 3 times weekly. Exercise capacity, respiratory mechanics, lung and systemic inflammation, and lung morphology were assessed.

RESULTS

Moderate aerobic exercise significantly increased the maximal running capacity of the HPS animals. The training decreased tissue elastance by 19 % (p = 0.01 compared to SHAM) and reduced frequency-dependent respiratory reactance at 0.5 Hz, 0.75 Hz, and 1.25 Hz frequencies compared to HPS animals (p < 0.05 for all). For the HPS + EA4 and HPS + EA8 groups IL-10 plasma concentration increased by 23 % and 31 % compared to SHAM (p < 0.001 both) and by 38 % and 47 % compared to HPS (p < 0.01 both). Nonetheless, AE did not alleviate lung tissue remodeling induced by HPS.

CONCLUSIONS

Moderate-intensity aerobic training improved maximum running capacity, reduced HPS-induced respiratory mechanics derangements at the lung regional level, and increased systemic IL-10 concentration, although it did not ameliorate lung tissue remodeling.

Disruption of Hepatic Sinusoidal Homeostasis Leads to Hepatopulmonary Syndrome

Hepatopulmonary syndrome (HPS) is a pulmonary vascular complication of liver disease and/or portal hypertension. HPS manifests as impaired gas exchange and hypoxemia due to intrapulmonary vascular dilatations and shunts. In response to primary liver disease, the abnormal adaptation of respiratory epithelial cells, pulmonary endothelial cells and immune cells leads to pulmonary microenvironment disequilibrium and HPS. In this review, we explore the pathophysiologic mechanisms of HPS, including vascular dilation, angiogenesis and alveolar dysfunction. The liver is the primary contributor to HPS, and liver transplantation is the only treatment that generally reverses HPS. We then discuss how disruption of hepatic sinusoidal homeostasis may impact the progression of HPS, mainly focusing on hepatocytes, cholangiocytes, LSECs and macrophages. As HPS occurs more commonly in advanced liver cirrhosis, we also discuss that normalisation of liver dysfunction and portal hypertension is crucial for the resolution of HPS. In conclusion, liver-targeted therapies may be effective in treating HPS.

Predictive models and clinical manifestations of intrapulmonary vascular dilatation and hepatopulmonary syndrome in patients with cirrhosis: Prospective comparative study

BACKGROUND

Patients with cirrhosis with hepatopulmonary syndrome (HPS) have a poorer prognosis. The disease has a subtle onset, symptoms are easily masked, clinical attention is insufficient, and misdiagnosis rates are high.

AIM

To compare the clinical characteristics of patients with cirrhosis, cirrhosis combined with intrapulmonary vascular dilatation (IPVD), and HPS, and to establish predictive models for IPVD and HPS.

METHODS

Patients with cirrhosis were prospectively screened at a liver-specialized university teaching hospital. Clinical information and blood samples were collected, and biomarker levels in blood samples were measured. Patients with cirrhosis were divided into three groups: Those with pure cirrhosis, those with combined IPVD, and those with HPS based on contrast-enhanced transthoracic echocardiography results and the pulmonary alveolar-arterial oxygen gradient values. Univariate logistic regression and Least Absolute Shrinkage and Selection Operator (LASSO) regression methods were utilized to identify risk factors for IPVD and HPS, and nomograms were constructed to predict IPVD and HPS.

RESULTS

A total of 320 patients were analyzed, with 101 diagnosed with IPVD, of whom 54 were diagnosed with HPS. There were statistically significant differences in clinical parameters among these three groups of patients. Among the tested biomarkers, sphingosine 1 phosphate, angiopoietin-2, and platelet-derived growth factor BB were significantly associated with IPVD and HPS in patients with cirrhosis. Following LASSO logistic regression screening, prediction models for IPVD and HPS were established. The area under the receiver operating characteristic curve for IPVD prediction was 0.792 (95% confidence interval [CI]: 0.737-0.847), and for HPS prediction was 0.891 (95%CI: 0.848-0.934).

CONCLUSION

This study systematically compared the clinical characteristics of patients with cirrhosis, IPVD, and HPS, and constructed predictive models for IPVD and HPS based on clinical parameters and laboratory indicators. These models showed good predictive value for IPVD and HPS in patients with cirrhosis. They can assist clinicians in the early prognosis assessment of patients with cirrhosis, ultimately benefiting the patients.

Placental growth factor modulates endothelial NO production and exacerbates experimental hepatopulmonary syndrome

Background & Aims

Hepatopulmonary syndrome (HPS) results from portal hypertension, with or without cirrhosis, and is marked by pulmonary vascular dilations leading to severe hypoxemia. Although placental growth factor (PlGF) is important for vascular growth and endothelial function, its role in HPS is unclear. This study investigated the involvement of PlGF in experimental models of HPS and in patients.

Methods

Circulating PlGF levels were measured in 64 controls and 137 patients with liver disease, with or without HPS. Two rat models, common bile duct ligation (CBDL) and long-term partial portal vein ligation (PPVL), were used. Plgf-knockout (Plgf -/-) rats were generated using CRISPR-Cas9. Lung RNA-sequencing analysis was performed in the CBDL model. The effects of PlGF on endothelial nitric oxide synthase (eNOS) activity in human pulmonary microvascular endothelial cells were also investigated.

Results

Circulating PlGF levels were significantly higher in patients with cirrhosis compared with healthy controls (29.4 ± 1.2 vs. 20.2 ± 0.8 pg/ml, p <0.0001), but no difference were found between patients with and without HPS. PlGF levels were not elevated in patients with extrahepatic portal hypertension. In Plgf -/- rats, there was a protective effect against CBDL-induced HPS, whereas PPVL-induced HPS severity remained unchanged. RNA sequencing coupled with ingenuity pathway analysis identified significant interactions between PlGF and pulmonary eNOS activity. Following CBDL, Plgf -/- rats showed decreased pulmonary eNOS activity and reduced circulating nitric oxide metabolites. In vitro, PlGF stimulation enhanced eNOS activity in human pulmonary microvascular endothelial cells, whereas PlGF knockdown led to a decrease.

Conclusions

These findings indicate that PlGF aggravates cirrhosis-induced HPS through modulation of pulmonary eNOS activity, and is not involved in HPS from extrahepatic portal hypertension.

Impact and implications

This study identified PlGF as a significant contributor to the exacerbation of HPS associated with cirrhosis, through its regulation of pulmonary nitric oxide production. Our findings demonstrated that PlGF deficiency mitigates the severity of both cirrhosis and HPS in the CBDL model, highlighting its potential as a therapeutic target in cirrhosis-induced HPS. Notably, this protective effect was absent in the PPVL model, which induces HPS associated with portal hypertension without cirrhosis. These results open avenues for novel pharmacological interventions aiming to improve outcomes for patients with cirrhosis-induced HPS.

Survival of patients with hepatopulmonary syndrome related to cirrhotic and non-cirrhotic (schistosomiasis) portal hypertension

BACKGROUND

The hepatosplenic schistosomiasis (HSS) with portal hypertension can cause vascular complications such as hepatopulmonary syndrome (HPS). HPS increases the risk of mortality in patients with cirrhosis; however, there is no data on the mortality of patients with HSS and HPS.

AIM

To perform a survival analysis of patients with HPS related to cirrhotic and non-cirrhotic (schistosomiasis) portal hypertension.

METHODS

From August 2023 to January 2024, medical records and the official mortality information service of 121 patients who participated in a cross-sectional study on HPS between 2010 and 2012 were analyzed. Survival curves were created using the Kaplan-Meier method, and comparisons were performed using the log-rank test. Cox regression models estimated the hazard ratios (HR).

RESULTS

Overall, data of 113 patients were analyzed; most (55.8%) had HSS and concomitant cirrhosis (HSS/cirrhosis). Meanwhile, HPS was present in 39 (34.5%) patients. Death occurred in 65 patients [57.5%; 95% confidence interval (CI): 48%-67%. The average time to death was lower in those with HPS when compared to those without HPS (3.37 years vs 5.65 years; P = 0.017). According to the cause of liver disease, patients with HSS/cirrhosis died earlier, and their risk of death was twice as high compared with patients with HSS without cirrhosis (HR: 2.17; 95%CI: 1.3-3.60; P = 0.003). Meanwhile, there were no differences when comparing the two groups with and without HPS (HR: 1.01; 95%CI: 0.59-1.73; P = 0.967).

CONCLUSION

Patients with HSS and concomitant cirrhosis had a lower survival rate, but there was no difference in survival regardless of the presence of HPS.

Disease trajectory and competing risks of patients with cirrhosis in the US

BACKGROUND

Cirrhosis is a dynamic disease process leading to liver-related death, which has increased by over 65% over the last decade. Unpredictable hepatic decompensation complications are a major source of morbidity and mortality. Thus, accurately characterizing disease progression through discrete stages of cirrhosis is critical towards implementing timely intervention and liver transplant (LT) waitlisting.

METHODS

A retrospective, longitudinal, population-cohort study of adult patients with cirrhosis from a US metropolitan area (2006-2012) was conducted. Clinical diagnoses were defined by ICD-9 and CPT codes. Cirrhosis stages were defined as: compensated without portal hypertension (Stage 1), compensated with portal hypertension (Stage 2), variceal bleeding (Stage 3), hepatic encephalopathy (Stage 4a), ascites (Stage 4b), and ≥2 different decompensating complications (Stage 5). Multivariate Fine-Gray competing risk survival analysis adjusted for clinicodemographic covariates.

RESULTS

Among 12,196 patients with cirrhosis, the mean (±SD) age was 56.8 (±11.7) years with a follow-up time of 2.35 (±1.81) years. A novel 5-stage disease progression framework was used. The 1-year mortality rates for each stage were 7.3% for Stage 1, 5.4% for Stage 2, 11.4% for Stage 3, 10.0% for Stage 4a, 20.2% for Stage 4b, and 43.8% for Stage 5. Compared to those in Stage 1, Stage 3 (sHR:1.83, 95% CI:1.36-2.48, P<0.001), Stage 4b (sHR:1.45, 95% CI:1.23-1.70, P<0.001), and Stage 5 (sHR:1.95, 95% CI:1.71-2.23, P<0.001) patients had higher risks of mortality. Additional disease progression rates were identified.

CONCLUSION

Even among patients with compensated cirrhosis, the 1-year mortality rate was as high as 7.3% and subsequently increases with each decompensation complication. This one-year mortality rate is higher than 5-years mortality rate reported in previously known non-US studies. The highest associated risk of death was observed among patients with ≥2 different decompensating complications (95.2%), variceal bleeding (83.2%) and ascites (44.9%). Overall, patients in advanced stages of cirrhosis were more likely to die than they were to receive a LT, suggesting that patients should be referred and waitlisted for LT earlier in the disease process.

New updates on hepatopulmonary syndrome: A comprehensive review

Hepatopulmonary syndrome (HPS) is a serious pulmonary vascular complication that causes arterial hypoxemia in the setting of liver disease. HPS has a progressive course and is associated with a two-fold increased risk of mortality relative to cirrhotic patients without HPS. It primarily affects patients with portal hypertension. The key pathological features of HPS include intrapulmonary angiogenesis and vascular dilations (IPVDs). The prevalence of HPS varies widely due to inconsistent diagnostic criteria and a lack of standardized protocols. Despite advances in understanding its pathophysiology, no effective curative treatments for HPS exist. Liver transplantation remains the only definitive treatment, improving survival and altering the disease natural course. This review explores the pathophysiology, clinical features, and therapeutic strategies for HPS, highlighting recent advances in the literature.

Cerebrovascular Accidents After Orthotopic Liver Transplantation in Patients with Hepatopulmonary Syndrome: A Case Series

Background: Hepatopulmonary syndrome (HPS), defined by the presence of pulmonary vascular dilatations that cause right-to-left transpulmonary shunting of venous blood with a consequential increase in the alveolar-arterial oxygen gradient, is a relatively frequent complication of chronic liver disease. While orthotopic liver transplantation (OLT) is indicated and often curative in HPS patients with end-stage liver disease (ESLD), little is known about the peri- and post-operative-period risks of CVA in OLT recipients with HPS. Case Presentation: We report a case series of five non-consecutive OLT recipients with HPS who developed ischemic and/or hemorrhagic CVAs during or shortly after OLT, raising concern that the risks of neurological complications remain increased even after OLT. Conclusions: Our case series hopes to highlight the importance of close vigilance in this subset of patients, at a time when there may be multiple issues to be addressed in facilitating post-operative recovery.

Health-related quality of life and frailty in liver cirrhosis

BACKGROUND AND OBJECTIVES

There is limited evidence concerning the predictive value of health-related quality of life (HRQoL) on the presence of frailty in the context of cirrhosis. We aimed to elucidate the relationship between HRQoL and multidimensional frailty and to determine which HRQoL dimension independently impacted frail phenotype in our established cohort.

METHODS

This was a prospective observational study by consecutively enrolling 355 patients with cirrhotic with decompensated signs in China. The HRQoL and frail phenotype were evaluated by the EuroQol-5D (EQ-5D) Questionnaire and Frailty Index, respectively. The relationship between EQ-5D utility index, as well as respective EQ-5D dimension, and Frailty Index was analysed according to the multiple linear regression analyses.

RESULTS

More than half of the patients (56.3%) reported problems in any dimension of the EQ-5D, suggestive of impaired HRQoL. Moreover, the proportion of patients experiencing some/extreme problems significantly increased across all five dimensions (all p<0.001) in correspondence to transition from the robust to frail phenotype. Multiple linear regression analyses demonstrated that age, ascites and hepatic encephalopathy were positively associated with Frailty Index, while EQ-5D utility index (standardised β coefficient= -0.442, p<0.001) negatively associated with Frailty Index. Notably, usual activities, self-care and mobility were the most influencing predictors associated with frailty.

CONCLUSIONS

Our results support a rapid HRQoL assessment via EQ-5D may assist in predicting multidimensional frailty, and usual activities, self-care and mobility tend to be remediable targets while taking their effect on frail phenotype into consideration among patients with cirrhosis.

Hepatopulmonary Syndrome and Liver Transplantation: Impact on Survival and Postoperative Complications

BACKGROUND Liver transplantation (LT) is the preferred treatment for patients with cirrhosis who have hepatopulmonary syndrome (HPS). However, the effect of HPS on LT remains controversial. We assessed the correlation between HPS severity and LT survival and compared the incidence of postoperative complications between patients with and without HPS undergoing LT. MATERIAL AND METHODS We retrospectively reviewed the recipients who received living-donor LT in our institute between January 2016 and July 2019. Patients with HPS (HPS group) and patients without HPS (non-HPS group) were included in our study. HPS is defined as a defect in arterial oxygenation caused by the presence of intrapulmonary vascular dilatations, which is found by transthoracic echocardiography with pre-existing liver cirrhosis. HPS severity was graded according to the value of partial pressure of arterial oxygen. The demographic characteristics and clinical outcomes between the HPS and non-HPS groups were compared. RESULTS A total of 181 patients were enrolled. Among them, 104 patients (57.5%) had HPS. The mean overall survival of HPS and non-HPS groups was 69.82±3.1 vs 63.36±3.8 months, with no significant difference (P=0.332). The overall survival between different degrees of HPS was also compared, and showed no significant difference (P=0.466). The HPS group had a higher incidence of delayed extubation (22.1% vs 10.4%, P=0.028) and chest pigtail catheter insertion (16.3% vs 10.4%, P=0.012). Nevertheless, it did not lead to a longer Intensive Care Unit/hospital stay or higher risk of short-term mortality. CONCLUSIONS Patients with HPS tend to have more post-LT pulmonary complications, but the overall survival is not adversely influenced, regardless of the severity of HPS.

Hepatopulmonary syndrome in biliary atresia children increased postoperative complications after liver transplantation

BACKGROUND

Hepatopulmonary syndrome (HPS) is a complication in biliary atresia (BA) children following hepatoportoenterostomy. Liver transplantation (LT) was the definitive treatment of HPS. However, little was known about the risk factors between HPS and mortalities. We aimed to evaluate the role of HPS and the predictors of complications after LT in BA children.

METHODS

One hundred and twenty (54 males and 66 females) children with BA receiving LT were retrospectively enrolled. The primary outcome was postoperative biliary/vascular complication rates and the secondary outcome was post-LT mortality rates.

RESULTS

Among 120 BA children receiving LT, six (5%) children were diagnosed with HPS before LT. The overall survival rate of LT in BA children was 80% and the overall survival rate of LT in BA children with and without HPS was 17% and 83%, respectively. Vascular complications and HPS were predictors for poor overall survival rates both in univariate logistic regression analyses (hazard ratio [HR], 11.63 and 5.96; P < 0.0001 and P = 0.001, respectively) and multivariate logistic regression analyses (HR, 10.02 and 4.16; P < 0.0001 and P = 0.007, respectively). Kaplan-Meier analysis indicated the predictive role of HPS on poor overall survival rates (P < 0.0001), higher risks of biliary complications (P < 0.0001), and higher risks of jaundice (P < 0.01) post-LT.

CONCLUSION

The present study comprising children over long-term follow-up revealed that the development of pre-LT HPS had a poor impact on overall survival rates and higher risks of biliary complications in BA children receiving LT.

Pulmonary vascular complications of cirrhosis: hepatopulmonary syndrome and portopulmonary hypertension

Hepatopulmonary syndrome (HPS) and portopulmonary hypertension (POPH) are two distinct pulmonary vascular complications seen in patients with liver disease and/or portal hypertension. HPS is characterized by disturbed gas exchange and hypoxemia because of intrapulmonary vascular dilatations. POPH is defined by pulmonary arterial hypertension, which might lead to right heart failure. HPS affects up to 30% of patients with end-stage liver disease requiring liver transplantation. POPH is rarer and affects 1-5% of this patient population. If not recognized and left untreated, these disorders result in significant mortality. This review provides an update on HPS and POPH and discusses their clinical characteristics, screening and diagnostic modalities, and management, including the place of liver transplantation.

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 unveiled: Exploring pathogenesis, diagnostic approaches, and therapeutic strategies

Hepatopulmonary syndrome (HPS) is a pulmonary complication of liver cirrhosis that causes an oxygenation defect. Many patients are asymptomatic at diagnosis or may have non-specific symptoms such as dyspnea. Since the diagnostic criteria for HPS have been established, its prevalence has been better estimated. HPS is an important prognostic indicator for patients undergoing evaluation for liver transplant. The implementation of the Model for End-stage Liver Disease exception policy has improved the outcomes of HPS; however, the mortality remains high. Here, we discuss the pathophysiology, diagnostic criteria, and recent experimental studies in HPS.

Hepatic BMAL1 and HIF1α regulate a time-dependent hypoxic response and prevent hepatopulmonary-like syndrome

The transcriptional response to hypoxia is temporally regulated, yet the molecular underpinnings and physiological implications are unknown. We examined the roles of hepatic Bmal1 and Hif1α in the circadian response to hypoxia in mice. We found that the majority of the transcriptional response to hypoxia is dependent on either Bmal1 or Hif1α, through shared and distinct roles that are daytime determined. We further show that hypoxia-inducible factor (HIF)1α accumulation upon hypoxia is temporally regulated and Bmal1 dependent. Unexpectedly, mice lacking both hepatic Bmal1 and Hif1α are hypoxemic and exhibit increased mortality upon hypoxic exposure in a daytime-dependent manner. These mice display mild liver dysfunction with pulmonary vasodilation likely due to extracellular signaling regulated kinase (ERK) activation, endothelial nitric oxide synthase, and nitric oxide accumulation in lungs, suggestive of hepatopulmonary syndrome. Our findings indicate that hepatic BMAL1 and HIF1α are key time-dependent regulators of the hypoxic response and can provide molecular insights into the pathophysiology of hepatopulmonary syndrome.

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.

High Prevalence and Clinical Relevance of Intrapulmonary Vascular Dilatations in Patients Undergoing TIPS Implantation

BACKGROUND & AIMS

Considerate patient selection is vital to ensure the best possible outcomes after transjugular intrahepatic portosystemic shunt (TIPS) insertion. However, data regarding the impact of intrapulmonary vascular dilatations (IPVDs) or hepatopulmonary syndrome (HPS) on the clinical course after TIPS implantation is lacking. Hence, this study aimed to investigate the relevance of IPVD and HPS in patients undergoing TIPS implantation.

METHODS

Contrast enhanced echocardiography and blood gas analysis were utilized to determine presence of IPVD and HPS. Multivariable competing risk analyses were performed to evaluate cardiac decompensation (CD), hepatic decompensation (HD), and liver transplant (LTx)-free survival within 1 year of follow-up.

RESULTS

Overall, 265 patients were included, of whom 136 had IPVD and 71 fulfilled the HPS criteria. Patients with IPVD had lower Freiburg index of post-TIPS survival (FIPS) scores, lower creatinine, and more often received TIPS because of variceal bleeding. Presence of IPVD was associated with a significantly higher incidence of CD (hazard ratio [HR], 1.756; 95% confidence interval [CI], 1.011-3.048; P = .046) and HD (HR, 1.841; 95% CI, 1.255-2.701; P = .002). However, LTx-free survival was comparable between patients with and without IPVD (HR, 1.081; 95% CI, 0.630-1.855; P = .780). Patients with HPS displayed a trend towards more CD (HR, 1.708; 95% CI, 0.935-3.122; P = .082) and HD (HR, 1.458; 95% CI, 0.934-2.275; P = .097) that failed to reach statistical significance. LTx-free survival did not differ in those with HPS compared with patients without HPS, respectively (HR, 1.052; 95% CI, 0.577-1.921; P = .870).

CONCLUSION

Screening for IPVD before TIPS implantation could help to further identify patients at higher risk of CD and HD.

Disrupted BMP-9 Signaling Impairs Pulmonary Vascular Integrity in Hepatopulmonary Syndrome

Rationale: Hepatopulmonary syndrome (HPS) is a severe complication of liver diseases characterized by abnormal dilation of pulmonary vessels, resulting in impaired oxygenation. Recent research highlights the pivotal role of liver-produced BMP-9 (bone morphogenetic protein-9) in maintaining pulmonary vascular integrity. Objectives: This study aimed to investigate the involvement of BMP-9 in human and experimental HPS. Methods: Circulating BMP-9 levels were measured in 63 healthy control subjects and 203 patients with cirrhosis with or without HPS. Two animal models of portal hypertension were employed: common bile duct ligation with cirrhosis and long-term partial portal vein ligation without cirrhosis. Additionally, the therapeutic effect of low-dose BMP activator FK506 was investigated, and the pulmonary vascular phenotype of BMP-9-knockout rats was analyzed. Measurements and Main Results: Patients with HPS related to compensated cirrhosis exhibited lower levels of circulating BMP-9 compared with patients without HPS. Patients with severe cirrhosis exhibited consistently low levels of BMP-9. HPS characteristics were observed in animal models, including intrapulmonary vascular dilations and an increase in the alveolar-arterial gradient. HPS development in both rat models correlated with reduced intrahepatic BMP-9 expression, decreased circulating BMP-9 level and activity, and impaired pulmonary BMP-9 endothelial pathway. Daily treatment with FK506 for 2 weeks restored the BMP pathway in the lungs, alleviating intrapulmonary vascular dilations and improving gas exchange impairment. Furthermore, BMP-9-knockout rats displayed a pulmonary HPS phenotype, supporting its role in disease progression. Conclusions: The study findings suggest that portal hypertension-induced loss of BMP-9 signaling contributes to HPS development.

Pulmonary Complications of Portal Hypertension

Portopulmonary hypertension (POPH), hepatopulmonary syndrome, and hepatic hydrothorax constitute significant complications of portal hypertension, with important implications for management and liver transplantation (LT) candidacy. POPH is characterized by obstruction and remodeling of the pulmonary resistance arterial bed. Hepatopulmonary syndrome is the most common pulmonary vascular disorder, characterized by intrapulmonary vascular dilatations causing impaired gas exchange. LT may improve prognosis in select patients with POPH. LT is the only effective treatment of hepatopulmonary syndrome. Hepatic hydrothorax is defined as transudative pleural fluid accumulation that is not explained by primary cardiopulmonary or pleural disease. LT is the definitive cure for hepatic hydrothorax.

Liver cirrhosis: current status and treatment options using western or traditional Chinese medicine

Liver cirrhosis arises from liver fibrosis and necroinflammation caused by various mechanisms of hepatic injury. It is a prevalent condition in clinical practice characterized by hepatocellular dysfunction, portal hypertension, and associated complications. Despite its common occurrence, the etiology and pathogenesis of liver cirrhosis remain incompletely understood, posing a significant health threat. Effective prevention of its onset and progression is paramount in medical research. Symptoms often include discomfort in the liver area, while complications such as sarcopenia, hepatic encephalopathy, ascites, upper gastrointestinal bleeding, and infection can arise. While the efficacy of Western medicine in treating liver cirrhosis is uncertain, Chinese medicine offers distinct advantages. This review explores advancements in liver cirrhosis treatment encompassing non-pharmacological and pharmacological modalities. Chinese medicine interventions, including Chinese medicine decoctions, Chinese patent medicines, and acupuncture, exhibit notable efficacy in cirrhosis reversal and offer improved prognoses. Nowadays, the combination of Chinese and Western medicine in the treatment of liver cirrhosis also has considerable advantages, which is worthy of further research and clinical promotion. Standardized treatment protocols based on these findings hold significant clinical implications.

Hepatopulmonary Syndrome: A Comprehensive Review

Hepatopulmonary syndrome (HPS) is defined by abnormally dilated blood vessels and shunts within the lungs, leading to impaired oxygen exchange. This condition results from intricate interactions between the liver, the gastrointestinal system, and the lungs. This complex system primarily affects pulmonary endothelial, immunomodulatory, and respiratory epithelial cells. Consequently, this contributes to pathological pulmonary changes characteristic of HPS. A classification system based on the severity of oxygen deficiency has been proposed for grading the physiological dysfunction of HPS. Contrast-enhanced echocardiography is considered the primary radiological evaluation for identifying abnormal blood vessel dilations within the lungs, which, combined with an elevated alveolar-arterial gradient, is essential for making the diagnosis. Liver transplantation is the sole effective definitive treatment that can reverse the course of the condition. Despite often being symptomless, HPS carries a significant risk of mortality before transplantation, regardless of the severity of liver disease. Meanwhile, there is varying data regarding survival rates following liver transplantation. The adoption of the model for end-stage liver disease (MELD) standard exception policy has notably improved the results for individuals with HPS compared to the period before MELD was introduced. This review offers a summary of the present understanding, highlighting recent advancements in the diagnosis and treatment of HPS. Furthermore, it aims to augment comprehension of the condition's fundamental mechanisms through insights derived from experimental models and translational research.

Physiologic changes in the hepatopulmonary syndrome before and after liver transplant: A longitudinal and predictor analysis

BACKGROUND AND AIMS

Hepatopulmonary syndrome (HPS) is a common complication of liver disease defined by abnormal oxygenation and intrapulmonary vascular dilatation, treated with liver transplantation. Little is known about changes in HPS physiological parameters over time. We sought to describe baseline clinical and physiological characteristics in HPS and their relationships, temporal changes in physiological parameters before and after transplant, and predictors of changes in oxygenation.

APPROACH AND RESULTS

This was a retrospective cohort study in the Canadian HPS Program (n = 132). Rates of change after diagnosis were: -3.7 (-6.4, -0.96) mm Hg/year for partial pressure of arterial oxygen (PaO 2 ); -26 (-96, 44) m/year for 6-minute walk distance, and 3.3% (-6.6, -0.011) predicted/year for diffusion capacity. Noninvasive shunt of ≥ 20% predicted a slower PaO 2 decline by 0.88 (0.36, 1.4) mm Hg/month. We identified 2 PaO 2 deterioration classes-"very severe disease, slow decliners" (PaO 2 45.0 mm Hg; -1.0 mm Hg/year); and "moderate disease, steady decliners" (PaO 2 65.5 mm Hg; -2.5 mm Hg/year). PaO 2 increased by 6.5 (5.3, 7.7) mm Hg/month in the first year after transplant. The median time to normalization was 149 (116, 184) days. Posttransplant improvement in PaO 2 was 2.5 (0.1, 4.9) mm Hg/month faster for every 10 mm Hg greater pretransplant orthodeoxia.

CONCLUSIONS

We present a large and long longitudinal data analysis in HPS. In addition to rates of physiological decline and improvement before and after liver transplantation, we present novel predictors of PaO 2 decline and improvement rates. Our findings enhance our understanding of the natural history of HPS and provide pathophysiologic clues. Importantly, they may assist providers in prognostication and prioritization before and after transplant.

[Hepatopulmonary syndrome]

The hepatopulmonary syndrome (HPS) is one of the lung diseases associated with cirrhosis and portal hypertension. It should be discussed for any dyspnea in cirrhotic patients. HPS is a pulmonary vascular disease characterized by intrapulmonary vascular dilatations (IPVD). The pathogenesis is complex and seems to rely on communications between the portal and pulmonary circulations. The diagnosis is based on a triad of liver disease and portal hypertension, evidence of IPVDs, and impaired gas exchange (alveolar-arterial oxygen difference [A-aO2]≥15mmHg). HPS impairs prognosis (23% survival at 5years) and patients' quality of life. Liver transplantation (LT) allows regression of IPDVD in almost 100% of cases, normalization of gas exchange and improves survival with a 5-year post-LT survival between 76 and 87%. It is the only curative treatment, indicated in patients with severe HPS, defined by an arterial partial pressure of oxygen (PaO2) below 60mmHg. When LT is not indicated or feasible, long-term oxygen therapy may be proposed as a palliative treatment. A better understanding of the pathophysiological mechanisms is needed to improve the therapeutic possibilities in a near future.

Cholangiocyte-derived exosomal long noncoding RNA PICALM-AU1 promotes pulmonary endothelial cell endothelial-mesenchymal transition in hepatopulmonary syndrome

Hepatopulmonary syndrome (HPS) is a severe lung injury caused by chronic liver disease, with limited understanding of the disease pathology. Exosomes are important mediators of intercellular communication that modulates various cellular functions by transferring a variety of intracellular components to target cells. Our recent studies have indicated that a new long noncoding RNA (lncRNA), PICALM-AU1, is mainly expressed in cholangiocytes, and is dramatically induced in the liver during HPS. However, the mechanism by which cholangiocyte-derived PICALM-AU1 regulates Endothelial-mesenchymal transition (EndMT) in HPS remains unclear. Here, we observed that PICALM-AU1 was synthesized in the cholangiocytes of the liver and then, secreted as exosomes into the serum; serum exosomal PICALM-AU1 levels were positively correlated with the severity of HPS in a rat model and in human patients. PICALM-AU1 carrying serum exosomes induced the EndMT of pulmonary microvascular endothelial cells (PMVECs) and promoted lung injury in vivo and in vitro. Furthermore, PICALM-AU1 acted as a molecular sponge for microRNA 144-3p (miR144-3p), resulting in the up-regulation of Zinc Finger E-Box Binding Homeobox 1 (ZEB1), a known target of EndMT and enhancement of EndMT, proliferation and migration of PMVECs. Taken together, our findings indicate that the cholangiocyte-derived exosomal lncRNA PICALM-AU1 plays a critical role in the EndMT in HPS lungs. Thus, it represents a potential therapeutic target for the treatment of HPS.

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.

[Pulmonary Complications in Patients with Liver Cirrhosis]

Portal hypertension is a clinical syndrome defined by an increased portal venous pressure. The most frequent cause of portal hypertension is liver cirrhosis, and many of the complications of cirrhosis, such as ascites and gastroesophageal variceal bleeding, are related to portal hypertension. Portal hypertension is a pathological condition caused by the accumulation of blood flow in the portal system. This blood flow retention reduces the effective circulation volume. To compensate for these changes, neurotransmitter hormone changes and metabolic abnormalities occur, which cause complications in organs other than the liver. A hepatic hydrothorax is fluid accumulation in the pleural space resulting from increased portal pressure. Hepatopulmonary syndrome and portopulmonary hypertension are the pulmonary complications in cirrhosis by deforming the vascular structure. Symptoms, such as dyspnea and hypoxia, affect the survival and the quality of life of patients. These lung complications are usually underestimated in the management of cirrhosis. This review briefly introduces the type of lung complications of cirrhosis.

Serum Soluble Vascular Endothelial Growth Factor Receptor 1 as a Potential Biomarker of Hepatopulmonary Syndrome

Background and Aims

The results of basic research implicate the vascular endothelial growth factor (VEGF) family as a potential target of hepatopulmonary syndrome (HPS). However, the negative results of anti-angiogenetic therapy in clinical studies have highlighted the need for markers for HPS. Therefore, we aimed to determine whether VEGF family members and their receptors can be potential biomarkers for HPS through clinical and experimental studies.

Methods

Clinically, patients with chronic liver disease from two medical centers were enrolled and examined for HPS. Patients were divided into HPS, intrapulmonary vascular dilation [positive contrast-enhanced echocardiography (CEE) and normal oxygenation] and CEE-negative groups. Baseline information and perioperative clinical data were compared between HPS and non-HPS patients. Serum levels of VEGF family members and their receptors were measured. In parallel, HPS rats were established by common bile duct ligation. Liver, lung and serum samples were collected for the evaluation of pathophysiologic changes, as well as the expression levels of the above factors.

Results

In HPS rats, all VEGF family members and their receptors underwent significant changes; however, only soluble VEGFR1 (sFlt-1) and the sFlt-1/ placental growth factor (PLGF) ratio were changed in almost the same manner as those in HPS patients. Furthermore, through feature selection and internal and external validation, sFlt-1 and the sFlt-1/PLGF ratio were identified as the most important variables to distinguish HPS from non-HPS patients.

Conclusions

Our results from animal and human studies indicate that sFlt-1 and the sFlt-1/PLGF ratio in serum are potential markers for HPS.

Role of Quantitation of Saline Bubble Studies in Patients with Liver Cirrhosis

OBJECTIVE

Microbubble contrast echocardiography with a late positive signal enables the detection of intrapulmonary vascular dilation, including hepatopulmonary syndrome, in patients with end-stage liver disease. We assessed the relationship between the severity of bubble study and clinical outcome.

METHODS

We retrospectively analyzed 163 consecutive patients with liver cirrhosis who underwent an echocardiogram with bubble study from 2018 to 2021. Patients who were diagnosed with a late positive signal were divided into three groups: grade 1 (1-9 bubbles), grade 2 (10-30 bubbles) and grade 3 (>30 bubbles).

RESULTS

Fifty-six percent of the patients had a late positive bubble study (grade 1: 31%, grade 2: 23%, grade 3: 46%). Patients with grade 3 had a significantly higher international normalized ratio, model for end-stage liver disease score and Child-Pugh score and a lower peripheral oxygen saturation compared with patients with a negative study. In patients undergoing liver transplant (LT), survival rates were similar among the groups (3-mo: >87%, 1-y: >87%, 2-y: >83%). However, survival rate was lower in grade 3 patients without LT (3-mo: 81%, 1-y: 64%, 2-y: 39%).

CONCLUSION

Patients with grade 3 had much worse mortality without LT compared with other groups. However, after LT, all grades had equal survival. Therefore, patients with grade 3 may be considered as higher priority for LT.

Cardiac index and hepatopulmonary syndrome in liver transplantation candidates: The pulmonary vascular complications of liver disease study

BACKGROUND AND AIMS

Hepatopulmonary syndrome (HPS) and a hyperdynamic circulation are common complications of advanced liver disease, but the relationship between HPS and cardiac index (CI) is poorly understood. We sought to compare CI in patients with and without HPS and to assess the relationship between CI and symptoms, quality of life, gas exchange, and exercise capacity among liver transplantation (LT) candidates. We performed a cross-sectional analysis within the Pulmonary Vascular Complications of Liver Disease 2 study, a multicenter prospective cohort study of patients being evaluated for LT. We excluded patients with obstructive or restrictive lung disease, intracardiac shunting, and portopulmonary hypertension. We included 214 patients (81 with HPS and 133 controls without HPS). Compared with controls, patients with HPS had a higher CI (least square mean 3.2 L/min/m 2 , 95% CI 3.1-3.4 vs. 2.8 L/min/m 2 , 95% CI 2.7-3.0, p < 0.001) after adjustment for age, sex, Model for End-stage Liver Disease-Sodium (MELD-Na) score and beta-blocker use, and a lower systemic vascular resistance. Among all LT candidates, CI was correlated with oxygenation (Alveolar-arterial oxygen gradient r =0.27, p < 0.001), intrapulmonary vasodilatation severity ( p < 0.001), and biomarkers of angiogenesis. Higher CI was independently associated with dyspnea and worse functional class and physical quality of life after adjusting for age, sex, MELD-Na, beta-blocker use, and HPS status. HPS was associated with a higher CI among LT candidates. Independent of HPS, higher CI was associated with increased dyspnea and worse functional class, quality of life, and arterial oxygenation.

LTSI Consensus Guidelines: Preoperative Pulmonary Evaluation in Adult Liver Transplant Recipients

The relationship between chronic liver disease and respiratory symptoms and hypoxia is well recognized. Over the last century, three pulmonary complications specific to chronic liver disease (CLD) have been characterized: hepatopulmonary syndrome, portopulmonary hypertension, and hepatic hydrothorax. Apart from that coexisting pulmonary disease like chronic obstructive lung disease and interstitial lung disease also complicate the outcomes after liver transplantation (LT). Assessment for evaluation of underlying pulmonary disorders is essential to improve outcomes in patients with CLD, posted for LT. This consensus guideline of the Liver Transplant Society of India (LTSI) provides a comprehensive review of pulmonary issues in CLD, related and unrelated to underlying liver disease and gives recommendations for pulmonary screening in specific clinical scenarios in adults with chronic liver disease planned for LT. This document also aims to standardize the strategies for preoperative evaluation of these pulmonary issues in this subset of patients. Proposed recommendations were based on selected single case reports, small series, registries, databases, and expert opinion. The paucity of randomized, controlled trials in either of these disorders was noted. Additionally, this review will highlight the lacunae in our current evaluation strategy, challenges faced, and will provide direction to potentially useful futuristic preoperative evaluation strategies.

Model for End-Stage Liver Disease/Pediatric End-Stage Liver Disease exception policy and outcomes in pediatric patients with hepatopulmonary syndrome requiring liver transplantation

Hepatopulmonary syndrome (HPS) is associated with increased waitlist mortality in liver transplantation (LT) candidates. Children with HPS are granted Model for End-Stage Liver Disease (MELD)/Pediatric End-Stage Liver Disease (PELD) exception points for waitlist prioritization in the United States based on criterion developed for adults. In this study, the impact of this MELD/PELD exception policy on post-LT survival in children was examined. A retrospective cohort of patients aged younger than 18 years with a MELD/PELD exception request who underwent LT between 2007 and 2018 were identified in the Scientific Registry of Transplant Recipients. Patients were stratified by waitlist partial pressure of arterial oxygen (PaO 2 ) to assess risk factors for waitlist mortality and post-LT survival. Among 3082 pediatric LT recipients included in the study, 124 patients (4%) received MELD/PELD exception points for HPS. Patients with HPS were a median age of 9 years (interquartile range: 6, 12 years), 54.8% were girls, and 54% were White. Most patients (87.9%) were listed with laboratory MELD/PELD scores <15. Waitlist mortality for patients with HPS exception points was rare and not different from patients without HPS. When stratified by pre-LT PaO 2 , hypoxemia severity was not associated with differences in 1-, 3-, or 5-year survival rates after LT ( p = 0.13). However, patients with HPS showed a slightly lower survival rate at 5 years compared with patients without HPS (88.7% vs. 93.4%; p = 0.04). MELD/PELD exceptions for children with HPS mitigated waitlist mortality, and recipients with HPS experienced excellent 5-year survival after LT, although slightly lower than in patients without HPS. Unlike adults with HPS, the severity of pre-LT hypoxemia in children does not impact post-LT survival. These data suggest that adult criteria for granting MELD/PELD exception points may not appropriately capture HPS severity in pediatric patients. Further prospective multicenter studies to examine the risk factors predicting negative survival outcomes in children with HPS are warranted.

MiR26-5p inhibits pathological pulmonary microvascular angiogenesis via down-regulating WNT5A

Objectives

Pathological micro angiogenesis is a key pathogenic factor in pulmonary diseases such as pulmonary hypertension and hepatopulmonary syndrome. More and more pieces of evidence show that excessive proliferation of pulmonary microvascular endothelial cells is the key event of pathological micro angiogenesis. The purpose of this research is to reveal the mechanism of miR26-5p regulating pulmonary microvascular hyperproliferation.

Materials and Methods

Hepatopulmonary syndrome rat model was made by common bile duct ligation. HE and IHC staining were used for analysis of the pathology of the rat. CCK8, transwell, and wound healing assay were used to assess miR26-5p or target gene WNT5A functioned toward PMVECs. microRNA specific mimics and inhibitors were used for up/down-regulated miR26-5p expression in PMVECs. Recombinant lentivirus was used for overexpression/knockdown WNT5A expression in PMVECs. And the regulation relationship of miR26-5p and WNT5A was analyzed by dual-luciferase reporter assay.

Results

qPCR showed that miR26-5p was significantly down-regulated in the course of HPS disease. Bioinformatics data showed that WNT5A was one of the potential key target genes of miR26-5p. Immunohistochemistry and qPCR analysis showed that WNT5A was largely expressed in pulmonary microvascular endothelial cells, in addition, this molecule was significantly up-regulated with the progression of the disease. Furthermore, dual luciferase reporter assay showed that miR26-5p could bind to WNT5A 3 'UTR region to inhibit WNT5A synthesis.

Conclusion

The results suggested MiR26-5p negatively regulated PMVECs proliferation and migration by WNT5A expression. Overexpression of miR26-5p may be a potentially beneficial strategy for HPS therapy.

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.

Shortness of breath due to portopulmonary hypertension and hepatopulmonary syndrome: diagnostic challenges and complex management approach in frail patients

A 60-year-old woman with a background of frailty, non-alcoholic fatty liver disease (NAFLD), cirrhosis and type 2 diabetes mellitus (T2DM), presented with worsening shortness of breath and a drop in oxygen saturation on sitting and standing up. Her chest X-ray demonstrated evidence of upper lobe venous diversion. Given the hypoxia, she had a computed tomography pulmonary angiography (CTPA) to rule out a pulmonary embolism. The only finding from the CTPA was pulmonary hypertension in the absence of any clots in the lungs. An ultrasound of the abdomen confirmed portal hypertension with splenomegaly and a cirrhotic liver, therefore, an initial diagnosis of portopulmonary hypertension and hepatopulmonary syndrome was made. The patient declined an agitated saline contrast echocardiography. Based on frailty she was not deemed to be a suitable candidate for a liver transplant and was discharged with a package of care alongside home oxygen therapy with periodic review in the gastroenterology clinic. She was assessed as stable with no new concerns while on home oxygen and diuretics. This case highlights challenges in diagnosing and managing patients with cirrhosis, portopulmonary hypertension and hepatopulmonary syndrome with a background of complex comorbidities and frailty.

Impact of hepatopulmonary syndrome in liver transplantation candidates and the role of angiogenesis

BACKGROUND

Hepatopulmonary syndrome affects 10-30% of patients with cirrhosis and portal hypertension. We evaluated the serum angiogenic profile of hepatopulmonary syndrome and assessed the clinical impact of hepatopulmonary syndrome in patients evaluated for liver transplantation.

METHODS

The Pulmonary Vascular Complications of Liver Disease 2 study was a multicentre, prospective cohort study of adults undergoing their first liver transplantation evaluation. Hepatopulmonary syndrome was defined as an alveolar-arterial oxygen gradient ≥15 mmHg (≥20 mmHg if age >64 years), positive contrast-enhanced transthoracic echocardiography and absence of lung disease.

RESULTS

We included 85 patients with hepatopulmonary syndrome and 146 patients without hepatopulmonary syndrome. Patients with hepatopulmonary syndrome had more complications of portal hypertension and slightly higher Model for End-Stage Liver Disease-Na score compared to those without hepatopulmonary syndrome (median (interquartile range) 15 (12-19) versus 14 (10-17), p=0.006). Hepatopulmonary syndrome patients had significantly lower 6-min walk distance and worse functional class. Hepatopulmonary syndrome patients had higher circulating angiopoietin 2, Tie2, tenascin C, tyrosine protein kinase Kit (c-Kit), vascular cell adhesion molecule 1 and von Willebrand factor levels, and lower E-selectin levels. Patients with hepatopulmonary syndrome had an increased risk of death (hazard ratio 1.80, 95% CI 1.03-3.16, p=0.04), which persisted despite adjustment for covariates (hazard ratio 1.79, 95% CI 1.02-3.15, p=0.04). This association did not vary based on levels of oxygenation, reflecting the severity of hepatopulmonary syndrome.

CONCLUSION

Hepatopulmonary syndrome was associated with a profile of abnormal systemic angiogenesis, worse exercise and functional capacity, and an overall increased risk of death.

The Edge of Unknown: Postoperative Critical Care in Liver Transplantation

Perioperative care of patients undergoing liver transplantation (LT) is very complex. Metabolic derangements, hypothermia, coagulopathy and thromboses, severe infections, and graft dysfunction can affect outcomes. In this manuscript, we discuss several perioperative problems that can be encountered in LT recipients. The authors present the most up-to-date information regarding predicting and treating hemodynamic instability, coagulation monitoring and management, postoperative ventilation strategies and early extubation, management of infections, and ESLD-related pulmonary complications. In addition, early post-transplant allograft dysfunction will be discussed.

Hepatopulmonary syndrome

Hepatopulmonary syndrome (HPS) is a pulmonary vascular complication of liver disease, which adversely affects prognosis. The disease is characterised by intrapulmonary vascular dilatations and shunts, resulting in impaired gas exchange. A complex interaction between the liver, the gut and the lungs, predominately impacting pulmonary endothelial cells, immune cells and respiratory epithelial cells, is responsible for the development of typical pulmonary alterations seen in HPS. Liver transplantation is the only therapeutic option and generally reverses HPS. Since the implementation of the model for end-stage liver disease (MELD) standard exception policy, outcomes in patients with HPS have been significantly better than they were in the pre-MELD era. This review summarises current knowledge and highlights what’s new regarding the diagnosis and management of HPS, and our understanding of pathogenesis based on experimental models and translational studies.

Pulmonary complications of portal hypertension: The overlooked decompensation

The systemic nature of cirrhosis and portal hypertension has long been recognized, and the amount of data characterizing the interplay between each system is becoming ever so complex. Lung involvement was among the first described associated entities in cirrhosis, with reports dating back to the late nineteenth century. However, it appears that throughout the years, interest in the pulmonary complications of portal hypertension has generally faded, especially in contrast to other decompensating events, as expertise in this field has primarily been concentrated in highly experienced tertiary care facilities and liver transplantation centers. Despite affecting up to 10%-15% of patients with advanced liver disease and having a proven prognostic impact, hepato-pulmonary syndrome, porto-pulmonary hypertension, and hepatic hydrothorax are frequently misdiagnosed, mistreated, or misinterpreted. This lack of precision might adversely impact patient care, referral to expert centers, and, ultimately, liver disease-related mortality and successful transplantation odds. The present minireview aims to increase awareness of the pulmonary complications of chronic liver disease by providing a brief overview of each of the three entities. The paper focuses on the essential theoretical aspects, addressing the most critical knowledge gaps on the one hand and, on the other hand, critically discussing one key issue for each complication.

A Retransplant Case for Hepatopulmonary Syndrome Without Liver Cirrhosis or Portosystemic Shunt After Living-Donor Liver Transplantation: A Case Report

Hepatopulmonary syndrome (HPS) is a disease of gas exchange caused by intrapulmonary shunting secondary to liver disease-associated intrapulmonary vascular dilation. HPS is characterized by the triad of cirrhosis, chronic liver disease, or portosystemic shunting (PSS); arterial hypoxemia; and intrapulmonary arteriovenous shunting in the absence of a primary cardiopulmonary anomaly. We encountered a rare case of HPS without liver disease or PSS. The patient was an 8-year-old girl who underwent living donor liver transplantation (LDLT) shortly after developing fulminant hepatitis at 11 months of her age. Eight years after LDLT, hypoxemia and shortness of breath developed. The shunt ratio on ^99mTc-macroaggregated albumin (MAA) lung perfusion scintigraphy (^99mTc-MAA lung scan) was 32%. The patient had no cardiopulmonary disease, so we diagnosed her illness as HPS. We did not find cirrhosis, chronic liver disease, or PSS as a cause of HPS. We thought the graft was the cause of HPS. A second transplantation was planned. One year after the diagnosis of HPS, the shunt ratio on ^99mTc-MAA lung scan worsened to 42%, digital clubbing appeared, and hypoxemia was worsening. Thus, we performed a second LDLT. After LDLT the shunt ratio on ^99mTc-MAA lung scan normalized (6%) and cyanosis resolved. We determined that the graft was the cause of HPS; the typical causes of HPS were not clearly revealed in the histologic examination of the second liver explant. Acute rejection occurred twice after LDLT, so we speculated that HPS occurred because the graft became stressed over the long term.

Hepatopulmonary syndrome delays postoperative recovery and increases pulmonary complications after hepatectomy

BACKGROUND

This study attempted to investigate the impact of hepatopulmonary syndrome (HPS) on postoperative outcomes in hepatitis B virus-induced hepatocellular carcinoma (HBV-HCC) patients.

METHODS

HBV-HCC patients undergoing primary curative hepatectomy for HCC in our hospital were diagnosed with HPS by contrast-enhanced echocardiography (CEE) and arterial blood gas analysis. Patients were divided into HPS, intrapulmonary vascular dilation (IPVD) (patients with positive CEE results and normal oxygenation) and control (patients with negative CEE results) groups. Baseline information, perioperative clinical data and postoperative pulmonary complications (PPCs) were compared among all groups. Cytokines in patient serums from each group (n = 8) were also assessed.

RESULTS

Eighty-seven patients undergoing hepatectomy from October 2019 to January 2020 were analyzed. The average time in the postanaesthesia care unit (112.10 ± 38.57 min) and oxygen absorption after extubation [34.0 (14.5-54.5) min] in the HPS group was longer than in IPVD [81.81 ± 26.18 min and 16.0 (12.3-24.0) min] and control [93.70 ± 34.06 min and 20.5 (13.8-37.0) min] groups. There were no significant differences in oxygen absorption time after extubation between HPS and control groups. The incidence of PPCs, especially bi-lateral pleural effusions in the HPS group (61.9%), was higher than in IPVD (12.5%) and control (30.0%) groups. Increased serum levels of the growth-regulated oncogene, monocyte chemoattractant protein, soluble CD40 ligand and interleukin 8 might be related to delayed recovery in HPS patients.

CONCLUSIONS

HPS patients with HBV-HCC suffer delayed postoperative recovery and are at higher risk for PPCs, especially bi-lateral pleural effusions, which might be associated with changes in certain cytokines.

Predictors of outcomes following liver transplant in hepatopulmonary syndrome: An OPTN database analysis

Hepatopulmonary syndrome (HPS) is a type of pulmonary vascular disease occurring exclusively in those with underlying liver disease, associated with significant mortality in patients awaiting liver transplantation (LT). LT is curative in HPS, and these patients are granted Model for End Stage Liver Disease (MELD) exception points to expedite LT. The purpose of this study is to use multivariable competing risk Accelerated Failure Time models and propensity matching to examine the relationship between pre-LT hypoxemia and post-LT outcomes in HPS. We performed a retrospective cohort study of UNOS/OPTN database of all adult patients undergoing LT between January 1, 2006 and January 12, 2020. Pre-LT PaO₂ was significantly associated with post-LT mortality in HPS, with each 1 mmHg increase in PaO₂ significantly decreasing the risk of post-LT mortality (coefficient 0.039, HR = 0.95, p = 0.001). HPS patients with a pre-LT PaO₂ < 54 mmHg demonstrated increased mortality following LT as compared to matched non-HPS cirrhotic patients. We conclude that HPS patients with a PaO₂, 54 mmHg are at increased risk of post-LT mortality and may identify high-risk patients who would benefit from additional resources during LT, and that the effects of HPS MELD exception points to optimize post-LT outcomes should be continuously re-evaluated.

M2 macrophage accumulation contributes to pulmonary fibrosis, vascular dilatation, and hypoxemia in rat hepatopulmonary syndrome

Hepatopulmonary syndrome (HPS) markedly increases the mortality of patients. However, its pathogenesis remains incompletely understood. Rat HPS develops in common bile duct ligation (CBDL)-induced, but not thioacetamide (TAA)-induced cirrhosis. We investigated the mechanisms of HPS by comparing these two models. Pulmonary histology, blood gas exchange, and the related signals regulating macrophage accumulation were assessed in CBDL and TAA rats. Anti-polymorphonuclear leukocyte (antiPMN) and anti-granulocyte-macrophage colony stimulating factor (antiGM-CSF) antibodies, clodronate liposomes (CL), and monocyte chemoattractant protein 1 (MCP1) inhibitor (bindarit) were administrated in CBDL rats, GM-CSF, and MCP1 were administrated in bone marrow-derived macrophages (BMDMs). Pulmonary inflammatory cell recruitment, vascular dilatation, and hypoxemia were progressively developed by 1 week after CBDL, but only occurred at 4 week after TAA. Neutrophils were the primary inflammatory cells within 3 weeks after CBDL and at 4 week after TAA. M2 macrophages were the primary inflammatory cells, meantime, pulmonary fibrosis, GM-CSFR, and CCR2 were specifically increased from 4 week after CBDL. AntiPMN antibody treatment decreased neutrophil and macrophage accumulation, CL or the combination of antiGM-CSF antibody and bindarit treatment decreased macrophage recruitment, resulting in pulmonary fibrosis, vascular dilatation, and hypoxemia in CBDL rats alleviated. The combination treatment of GM-CSF and MCP1 promoted cell migration, M2 macrophage differentiation, and transforming growth factor-β1 (TGF-β1) production in BMDMs. Conclusively, our results highlight neutrophil recruitment mediates pulmonary vascular dilatation and hypoxemia in the early stage of rat HPS. Further, M2 macrophage accumulation induced by GM-CSF/GM-CSFR and MCP1/CCR2 leads to pulmonary fibrosis and promotes vascular dilatation and hypoxemia, as a result, HPS develops.

Diagnosis of Hepatopulmonary Syndrome in a Large Integrated Health System

BACKGROUND & AIMS

Data on the accuracy of the diagnosis of hepatopulmonary syndrome (HPS) in cirrhosis is limited. We evaluated the clinical characteristics of patients with International Classification of Diseases (ICD) codes for hepatopulmonary syndrome (HPS) in a large integrated health system.

METHODS

A retrospective review of encounters was performed of all patients with ICD-9-CM and/or ICD-10-CM diagnosis of cirrhosis and HPS from 2014-2019 in a multi-state health system. Demographics and cardiopulmonary testing closest to the time of HPS diagnosis were recorded. HPS was defined using standard criteria.

RESULTS

A total of 42,749 unique individuals with cirrhosis were identified. An ICD diagnosis of HPS was found in 194 patients (0.45%), of which 182 had clinically confirmed cirrhosis. 143 (78.5%) underwent contrast-enhanced transthoracic echocardiography, and 98 (54%) had delayed shunting. Among them, 61 patients had a documented arterial blood gas, with 53 showing abnormal oxygenation (A-a gradient of >15 mm Hg). 12 were excluded due to significant pulmonary function test abnormalities and abnormal oxygenation from other cardiopulmonary diseases. Ultimately, 41 (22.5%) fulfilled the criteria for HPS. When stratifying those with an ICD code diagnosis of HPS into HPS, no HPS and indeterminate HPS groups, based on standard diagnostic criteria for HPS, we found that the confirmed HPS patients had similar complications except for less portopulmonary hypertension, worse gas exchange, less cardiopulmonary disease and were more often diagnosed in transplant centers.

CONCLUSIONS

The diagnosis of HPS by ICD code is made in an extremely small subset of a sizeable cirrhotic cohort. When made, only a minority of these patients meet diagnostic criteria. Our findings highlight the need for improved education and more effective screening algorithms.

A Simple and Quick Screening Method for Intrapulmonary Vascular Dilation in Cirrhotic Patients Based on Machine Learning

Background and Aims

Screening for hepatopulmonary syndrome in cirrhotic patients is limited due to the need to perform contrast enhanced echocardiography (CEE) and arterial blood gas (ABG) analysis. We aimed to develop a simple and quick method to screen for the presence of intrapulmonary vascular dilation (IPVD) using noninvasive and easily available variables with machine learning (ML) algorithms.

Methods

Cirrhotic patients were enrolled from our hospital. All eligible patients underwent CEE, ABG analysis and physical examination. We developed a two-step model based on three ML algorithms, namely, adaptive boosting (termed AdaBoost), gradient boosting decision tree (termed GBDT) and eXtreme gradient boosting (termed Xgboost). Noninvasive variables were input in the first step (the NI model), and for the second step (the NIBG model), a combination of noninvasive variables and ABG results were used. Model performance was determined by the area under the curve of receiver operating characteristics (AUCROCs), precision, recall, F1-score and accuracy.

Results

A total of 193 cirrhotic patients were ultimately analyzed. The AUCROCs of the NI and NIBG models were 0.850 (0.738–0.962) and 0.867 (0.760–0.973), respectively, and both had an accuracy of 87.2%. For both negative and positive cases, the recall values of the NI and NIBG models were both 0.867 (0.760–0.973) and 0.875 (0.771–0.979), respectively, and the precisions were 0.813 (0.690–0.935) and 0.913 (0.825–1.000), respectively.

Conclusions

We developed a two-step model based on ML using noninvasive variables and ABG results to screen for the presence of IPVD in cirrhotic patients. This model may partly solve the problem of limited access to CEE and ABG by a large numbers of cirrhotic patients.

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.