Effect of PAH specific therapy on pulmonary hemodynamics and six-minute walk distance in portopulmonary hypertension: a systematic review and meta-analysis

Pulmonary Assessment of the Liver Transplant Recipient

Respiratory symptoms and hypoxemia can complicate chronic liver disease and portal hypertension. Various pulmonary disorders affecting the pleura, lung parenchyma, and pulmonary vasculature are seen in end-stage liver disease, complicating liver transplantation (LT). Approximately 8% of cirrhotic patients in an intensive care unit develop severe pulmonary problems. These disorders affect waiting list mortality and posttransplant outcomes. A thorough history, physical examination, and appropriate laboratory tests help diagnose and assess the severity to risk stratify pulmonary diseases before LT. Hepatopulmonary syndrome (HPS), portopulmonary hypertension (POPH), and hepatic hydrothorax (HH) are respiratory consequences specific to cirrhosis and portal hypertension. HPS is seen in 5-30% of cirrhosis cases and is characterized by impaired oxygenation due to intrapulmonary vascular dilatations and arteriovenous shunts. Severe HPS is an indication of LT. The majority of patients with HPS resolve their hypoxemia after LT. When pulmonary arterial hypertension occurs in patients with portal hypertension, it is called POPH. All other causes of pulmonary arterial hypertension should be ruled out before labeling as POPH. Since severe POPH (mean pulmonary artery pressure [mPAP] >50 mm Hg) is a relative contraindication for LT, it is crucial to screen for POPH before LT. Those with moderate POPH (mPAP >35 mm Hg), who improve with medical therapy, will benefit from LT. A transudative pleural effusion called hepatic hydrothorax (HH) is seen in 5-10% of people with cirrhosis. Refractory cases of HH benefit from LT. In recent years, increasing clinical expertise and advances in the medical field have resulted in better outcomes in patients with moderate to severe pulmonary disorders, who undergo LT.

Portopulmonary Hypertension

PoPH is a well-recognized complication of portal hypertension with or without cirrhosis and is classified as a subset of PAH. Identification of PoPH is crucial as it has a major impact on prognosis and liver transplant candidacy. Echocardiogram is the initial screening tool of choice and the patient should proceed to RHC for confirmation. PAH-directed therapy is the treatment of choice, allowing the patient to achieve a hemodynamic threshold to undergo a liver transplant safely.

Portopulmonary Hypertension: Management and Liver Transplantation Evaluation

Portopulmonary hypertension (POPH) affects 5% to 6% of patients with advanced liver disease and accounts for 5% to 15% of pulmonary arterial hypertension (PAH) cases. Compared with idiopathic PAH, POPH is associated with significantly worse survival. Recent studies have improved our understanding of the role of both PAH therapy and liver transplantation (LT) in the management of POPH and their impact on overall prognosis. We performed a review of the published literature to summarize the available evidence and guidelines regarding the diagnosis and management of POPH. POPH is defined by the presence of precapillary PH in the context of portal hypertension. POPH is associated with increased perioperative risk at the time of LT, which can be stratified by mean pulmonary arterial pressure and pulmonary vascular resistance. Screening with echocardiography is recommended in all LT candidates to facilitate detection and treatment of POPH. Despite a paucity of evidence, POPH is treated similarly to idiopathic PAH with PAH therapy. These therapies are associated with improved pulmonary hemodynamics and facilitation of safe LT. LT can result in improvement or resolution of POPH in half of patients and has been associated with improved survival in highly selected patients. The prognosis in POPH is poor and is impacted by the severity of both PH and liver disease. Management with a combination of PAH therapy and LT in selected patients has been associated with improved pulmonary hemodynamics and survival.

Pulmonary hypertension due to high cardiac output

Pulmonary hypertension (PH) is usually associated with a normal or decreased cardiac output (CO). Less commonly, PH can occur in the context of a hyperdynamic circulation, characterized by high CO (>8 L/min) and/or cardiac index ≥4 L/min/m² in the setting of a decreased systemic vascular resistance. PH due to high CO can occur due to multiple conditions and in general remains understudied. In this review article we describe the pathophysiology, etiology, diagnosis, hemodynamic characteristics, and management of PH in the setting of high CO. It is important to recognize this distinct entity as PH tends to improve with treatment of the underlying etiology and PH specific therapies may worsen the hemodynamic state.

Temporal Trends in Portopulmonary Hypertension Model for End-stage Liver Disease Exceptions and Outcomes

Model for end-stage liver disease (MELD) exception criteria for portopulmonary hypertension (POPH) were created to prioritize patients for liver transplant before POPH progression. Little is known about trends in POPH exception frequency, disease severity, pulmonary hypertension treatment patterns, or outcomes since the POPH MELD exception began.

Portopulmonary Hypertension: A Review of the Current Literature

Portopulmonary hypertension is defined as the development of pulmonary arterial hypertension in the setting of portal hypertension with or without liver cirrhosis. Portal hypertension-associated haemodynamic changes, including hyperdynamic state, portosystemic shunts and splanchnic vasodilation, induce significant alterations in pulmonary vascular bed and play a pivotal role in the pathogenesis of the disease. If left untreated, portopulmonary hypertension results in progressive right heart failure, with a poor prognosis. Although Doppler echocardiography is the best initial screening tool for symptomatic patients and liver transplantation candidates, right heart catheterisation remains the gold standard for the diagnosis of the disease. Severe portopulmonary hypertension exerts a prohibitive risk to liver transplantation by conferring an elevated perioperative mortality risk. It is important for haemodynamic parameters to correspond with non-severe portopulmonary hypertension before patients can proceed with the liver transplantation. Small uncontrolled studies and a recent randomised controlled trial have reported promising results with vasodilatory therapies in clinical and haemodynamic improvement of patients, allowing a proportion of patients to undergo liver transplantation. In this review, the epidemiology, pathogenesis, diagnostic approach and management of portopulmonary hypertension are discussed. We also highlight fields of ongoing investigation pertinent to risk stratification and optimal patient selection to maximise long-term benefit from currently available treatments.

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.

Portopulmonary hypertension: prognosis and management in the current treatment era - results from the REHAP registry

BACKGROUND

Portopulmonary hypertension (PoPH) is a rare condition with poorer survival compared to idiopathic/familial pulmonary arterial hypertension (IPAH/FPAH).

AIMS

To compare the characteristics, survival, prognostic factors and management of PoPH and IPAH/FPAH patients and to assess the impact of treatment on survival of PoPH patients.

METHODS

Analysis of data of prevalent and incident PoPH patients enrolled in the Spanish registry of PAH (REHAP) from January 1998 to December 2017 and comparison with IPAH/FPAH patients. Variables analysed: patient and disease (PAH and liver) characteristics, first-line PAH-targeted therapy, causes of death, prognostic factors and survival (according to aetiology and treatment in PoPH patients).

RESULTS

Compared to IPAH/FPAH patients (n = 678), patients with PoPH (n = 237) were predominantly men, older and had better functional class and higher prevalence of ascites. Haemodynamics were better. Biomarkers for heart failure were worse. Age- and sex-adjusted 5-year survival rate from diagnosis was 49.3% for PoPH patients and 68.7% for IPAH patients (P < 0.001). Treated PoPH had better survival than non-treated. PAH- and liver-related causes accounted for 30.2% and 24.7% of deaths in PoPH patients. PoPH patients were less likely to receive first-line PAH-targeted therapy and this was associated with greater mortality. Increasing age, worse exercise capacity and ascites were independent prognostic factors of poorer survival; first-line oral monotherapy was associated with improved survival. Eight (3.4%) PoPH patients underwent liver transplantation.

CONCLUSIONS

PoPH patients are undertreated and show poorer survival than IPAH/FPAH patients. First-line treatment with PAH-targeted therapy was associated with better survival. Presence of ascites was a predictor of mortality.

Epigenetic Regulation of Pulmonary Arterial Hypertension-Induced Vascular and Right Ventricular Remodeling: New Opportunities?

Pulmonary artery hypertension (PAH) is a rare chronic disease with high impact on patients’ quality of life and currently no available cure. PAH is characterized by constant remodeling of the pulmonary artery by increased proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs), fibroblasts (FBs) and endothelial cells (ECs). This remodeling eventually leads to increased pressure in the right ventricle (RV) and subsequent right ventricle hypertrophy (RVH) which, when left untreated, progresses into right ventricle failure (RVF). PAH can not only originate from heritable mutations, but also develop as a consequence of congenital heart disease, exposure to drugs or toxins, HIV, connective tissue disease or be idiopathic. While much attention was drawn into investigating and developing therapies related to the most well understood signaling pathways in PAH, in the last decade, a shift towards understanding the epigenetic mechanisms driving the disease occurred. In this review, we reflect on the different epigenetic regulatory factors that are associated with the pathology of RV remodeling, and on their relevance towards a better understanding of the disease and subsequently, the development of new and more efficient therapeutic strategies.

Hepatopulmonary Syndrome and Portopulmonary Hypertension: Management in Liver Transplantation in the Horizon 2020

Hepatopulmonary syndrome (HPS) is characterized by intrapulmonary microvasculature dilatation that causes intrapulmonary shunting and leads to a gas exchange abnormality in the presence of liver diseases, which is the most common cause of respiratory insufficiency in these patients. HPS doubles the risk of death, and liver transplantation (LT) is the only curative therapeutic option so it should be considered in patients with severe HPS, with excellent survival rates post-LT. However, pretransplant Pao₂ <45 mm Hg has been associated with an increase in post-transplant morbidity and mortality, but it does not imply a contraindication for LT. The resolution of HPS usually occurs within 6 months post-LT, but it can take 1 year. Portopulmonary hypertension (PoPH) is defined as pulmonary arterial hypertension (PAH) that develops in the setting of portal hypertension with or without liver disease in the absence of other causes of PAH. The prevalence of PoPH is 5% to 10% among liver transplant (LT) candidates. The impact of LT on PoPH is unpredictable. Therefore, despite conferring a high morbidity and mortality, PoPH itself is not an indication for liver transplantation. It may be considered a contraindication for LT in severe cases.

Pulmonary manifestations of chronic liver disease: a comprehensive review

Hepatopulmonary syndrome (HPS) and porto-pulmonary hypertension (PoPH) represent relatively common pulmonary vascular complications of advanced liver disease. Despite distinct differences in their pathogenetic background, both clinical states are characterized by impaired arterial oxygenation and limited functional status, and are associated with increased pre-transplantation mortality. Accumulation of ascitic fluid in the pleural cavity, known as hepatic hydrothorax (HH), is another frequent manifestation of decompensated cirrhosis, which may cause severe respiratory dysfunction, depending on the volume of the effusion, the rapidity of its development and its resistance to therapeutic measures. Orthotopic liver transplantation constitutes the only effective treatment able to resolve the pulmonary complications of liver disease. A prioritization policy for liver transplantation has evolved over the past years regarding advanced stages of HPS, yielding favorable outcomes regarding post-transplantation survival and HPS resolution. In contrast, severe PoPH is associated with poor post-transplantation survival. Hence, liver transplantation is recommended only for patients with PoPH and an acceptable reduction in pulmonary pressure values, after receiving PoPH-targeted vasodilating therapy. This review focuses on basic pathogenetic and diagnostic principles and discusses the current therapeutic approaches regarding HPS, PoPH, and HH.

Liver transplantation and cardiac illness: Current evidences and future directions

Contraindications to liver transplantation are gradually narrowing. Cardiac illness and chronic liver disease may manifest independently or may be superimposed on each other due to shared pathophysiology. Cardiac surgery involving the cardiopulmonary bypass in patients with Child-Pugh Class C liver disease is associated with a high risk of perioperative morbidity and mortality. Liver transplantation involves hemodynamic perturbations, volume shifts, coagulation abnormalities, electrolyte disturbances, and hypothermia, which may prove fatal in patients with cardiac illness depending upon the severity. Additionally, cardiovascular complications are the major cause of adverse postoperative outcomes after liver transplantation even in the absence of cardiac pathologies. Clinical decision-making has remained an unsettled issue in these clinical scenarios. The absence of randomized clinical studies has further crippled our endeavours for a consensus on the management of patients with end-stage liver disease with cardiac illness. This review seeks to address this complex clinical setting by gathering information from published literature. The management algorithm in this review may facilitate clinical decision making and augur future research.

Treatment Barriers in Portopulmonary Hypertension

Portopulmonary hypertension (PoPH) is a form of pulmonary arterial hypertension (PAH) that can develop as a complication of portal hypertension. Treatment of PoPH includes PAH-specific therapies, and in certain cases, such therapies are necessary to facilitate a successful liver transplantation. A significant number of barriers may limit the adequate treatment of patients with PoPH and explain the poorer survival of these patients when compared to patients with other types of PAH. Until recently, only one randomized controlled trial has included PoPH patients, and the majority of treatment data have been derived from relatively small observational studies. In the present article, we review some of the barriers in the treatment of patients with PoPH and implications for liver transplantation.

Survival in portopulmonary hypertension: Outcomes of the United Kingdom National Pulmonary Arterial Hypertension Registry

BACKGROUND

Portopulmonary hypertension (PoPH) is a rare condition associated with poor survival, and the effect of modern therapies that target pulmonary arterial hypertension (PAH) on long-term outcome is unknown. This study investigated the baseline characteristics and survival in the cohort of patients diagnosed with PoPH in the United Kingdom National Pulmonary Hypertension Service.

METHODS

A retrospective review was conducted of all incident treatment-naïve patients with PoPH within the United Kingdom national registry diagnosed between January 2001 and December 2010.

RESULTS

Patients with PoPH (n = 110) had survival rates of 85%, 60%, and 35% at 1, 3, and 5 years. The prevalence of PoPH was 0.85 cases/1 million. Mean age at diagnosis was 53 ± 12 years, with a balanced distribution in gender. Alcohol (n = 57) and hepatitis C (n = 10) were the most common causes of portal hypertension. Phosphodiesterase V inhibitors were the most frequently used targeted therapy, in 63.6% (n = 70) of patients, endothelin receptor antagonists were used in 10% (n = 11) and prostacyclin analogs in 12.7% (n = 14). Univariate and multivariate analysis of baseline characteristics did not demonstrate a significant influence of severity of portal hypertension or liver cirrhosis, World Health Organization Functional Class, cardiopulmonary hemodynamics, or year of diagnosis on survival.

CONCLUSIONS

Survival of patients with PoPH remains poor despite targeted therapy and worse than patients with idiopathic PAH. The benefit of PAH therapies in PoPH on long-term morbidity and mortality outcomes needs further consideration and study.

What's new in the treatment of portopulmonary hypertension?

Portopulmonary hypertension (POPH) is a complication of portal hypertension characterized by pulmonary vasoconstriction and vascular remodeling that can lead to right heart failure and death. Differentiation of POPH from other causes of pulmonary hypertension, such as volume overload or a hyperdynamic high flow state, is critical because a diagnosis of POPH has significant implications for liver transplant risk stratification, Model for End Stage Liver Disease exception points, and the use of pulmonary arterial hypertension-(PAH) specific therapy. Currently, there are 12 approved medications for the treatment of PAH in the US, and three of these were approved in 2013. This review will discuss the diagnosis, evaluation and management of POPH and the role of recently approved PAH therapies in the treatment of POPH.

[Hepatocardiac disorders : Interactions between two organ systems]

Interactions between the hepatic portal and cardiovascular systems are frequently found in patients with liver disease. Cirrhotic cardiomyopathy (CCMP) is defined as reduced cardiac function in patients with liver cirrhosis in the absence of other known causes of cardiac disease. The typical hyperdynamic circulatory state by means of increased cardiac output and reduced systemic vascular resistance may mask left ventricular failure. Portopulmonary hypertension (POPH) is defined as increased pulmonary arterial pressure and the presence of portal hypertension, and is associated with increased mortality. Targeted medical therapies include vasodilators such as prostanoids, endothelin receptor antagonists and phosphodiesterase-5 inhibitors. Hypoxic or ischaemic hepatitis (HH) is defined by a sharp increase of serum aminotransferase levels due to liver cell necrosis as result of cardiac, circulatory or respiratory failure. An overview of these diseases is provided in this article.