Outcomes of liver transplantation in patients with hepatopulmonary syndrome in the pre and post-MELD eras: A systematic review

Deadly intersection: Schistosomiasis, hepatopulmonary syndrome, and cirrhosis

In this editorial, we comment on the article by Rolim et al in World Journal of Hepatology, which highlights the impacts of hepatopulmonary syndrome (HPS) related to schistosomiasis in patients with and without cirrhosis. Schistosomiasis, a parasitic disease affecting millions worldwide, frequently leads to portal hypertension. Its outcomes are more devastating in cirrhosis than in non-cirrhotic portal hypertension, due to the complex interplay between cirrhosis and HPS, a severe pulmonary vascular complication. Cirrhosis distorts hepatic architecture, impairs portal blood flow, and triggers systemic vascular changes. Schistosomiasis exacerbates portal hypertension and inflammation, further injuring the liver. In non-cirrhotic portal hypertension, significant vascular resistance occurs, but preserved liver function mitigates systemic effects. In contrast, cirrhosis amplifies hypoxia, worsens pulmonary shunting, and predisposes patients to respiratory failure, infection, and death. In a retrospective study of 113 patients, Rolim et al found that cirrhosis had an impact on mortality, yet the presence of HPS did not significantly affect survival. While cirrhosis worsening outcomes are anticipated, HPS should theoretically worsen survival by impairing oxygenation. Early diagnosis, parasite control, and managing cirrhosis-related complications are critical for schistosomiasis-related liver disease. Understanding these differences underscores the importance of integrating liver health into global schistosomiasis management strategies.

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.

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.

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.

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.

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.

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.

Abdominal Organ Transplantation: Noteworthy Literature in 2021

This review highlights noteworthy literature pertinent to anesthesiologists and critical care physicians caring for patients undergoing abdominal organ transplantation. In 2021, we identified noteworthy papers from over 1,200 peer-reviewed publications on pancreatic transplantation, over 1,400 on intestinal transplantation, and over 9,000 on kidney transplantation. The liver transplantation section focuses on clinical trials and systematic reviews and meta-analyses published in 2021 and features 20 selected papers. COVID-19 and abdominal organ transplantation are featured in an independent section.