Model for end-stage liver disease (MELD) exception for portopulmonary hypertension

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.

Regional Social Vulnerability is Associated With Geographic Disparity in Waitlist Outcomes for Patients With Non-Hepatocellular Carcinoma Model for End-stage Liver Disease Exceptions in the United States

OBJECTIVE

This study was undertaken to evaluate the role of regional social vulnerability in geographic disparity for patients listed for liver transplantation with non-hepatocellular carcinoma (HCC) model for end-stage liver disease (MELD) exceptions.

SUMMARY AND BACKGROUND

Prior work has demonstrated regional variability in the appropriateness of MELD exceptions for diagnoses other than HCC.

METHODS

Adults listed at a single center for first-time liver-only transplantation without HCC after June 18, 2013 in the Scientific Registry of Transplant Recipients database as of March 2021 were examined. Candidates were mapped to hospital referral regions (HRRs). Adjusted likelihood of mortality and liver transplantation were modeled. Advantaged HRRs were defined as those where exception patients were more likely to be transplanted, yet no more likely to die in adjusted analysis. The Centers for Disease Control's Social Vulnerability Index (SVI) was used as the measure for community health. Higher SVIs indicate poorer community health.

RESULTS

There were 49,494 candidates in the cohort, of whom 4337 (8.8%) had MELD exceptions. Among continental US HRRs, 27.3% (n = 78) were identified as advantaged. The mean SVI of advantaged HRRs was 0.42 versus 0.53 in nonadvantaged HRRs ( P = 0.002), indicating better community health in these areas. Only 25.3% of advantaged HRRs were in spatial clusters of high SVI versus 40.7% of nonadvantaged HRRs, whereas 44.6% of advantaged HRRs were in spatial clusters of low SVI versus 38.0% of nonadvantaged HRRs ( P = 0.037).

CONCLUSIONS

An advantage for non-HCC MELD exception patients is associated with lower social vulnerability on a population level. These findings suggest assigning similar waitlist priority to all non-HCC exception candidates without considering geographic differences in social determinants of health may actually exacerbate rather than ameliorate disparity.

Resolution of Severe Portopulmonary Hypertension With Inhaled Treprostinil and Liver Transplantation

Portopulmonary hypertension is a rare condition with a poor prognosis. Prompt management is essential for liver transplantation eligibility, a potentially curative option. This report presents a case of severe portopulmonary hypertension that resolved with a conservative therapeutic regimen of tadalafil, macitentan, and inhaled treprostinil, which ultimately enabled successful liver transplantation. There was no recurrence of pulmonary hypertension after transplantation, and the patient was weaned off most pulmonary arterial hypertension therapies. This case report is the first to provide evidence that inhaled treprostinil is a safe and effective alternative to continuous intravenous prostacyclins in portopulmonary hypertension.

When Pulmonary Arterial Hypertension may be Associated with Portal Hypertension: A Case Report of Two Different Hepatic Disorders in One Patient with Pulmonary Hypertension

BACKGROUND

pulmonary arterial hypertension (PAH) is a rare complication of hepatic diseases with portal hypertension that, however, has a significant influence on prognosis. We present a mini-review of how to diagnose and treat it based on a clinical case.

CASE PRESENTATION

in early childhood, a patient had portal hypertension associated with cavernous transformation of the portal vein. It was successfully treated by reno-splenic surgery. At the age of 20 years, this patient experienced increased dyspnea at minimal physical activity after the hepatic biopsy due to a hepatocellular adenoma. The examination in the specialized unit showed PAH, which was evaluated as associated with portal hypertension (PAH-PoH). The specific two-drug combination therapy was started with prominent improvement in patient's state. Successful surgical tumor treatment was provided some months later. The practical and clinical approaches to the diagnosis and treatment of PAH-PoH are discussed. It was emphasized that not all patients with portal hypertension have pulmonary hypertension, which needs to be treated. A lot of evidence gaps exist in management of these patients.

CONCLUSION

all patients, even with past history of portal hypertension, should be monitored closely and screened for PAH earlier, for better results of treatment.

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.

Multivisceral Transplant in a Patient With Portopulmonary Hypertension: A Case Report

Portopulmonary hypertension, a type of pulmonary arterial hypertension in the setting of cirrhotic or noncirrhotic portal hypertension, is associated with elevated morbidity and mortality during and after transplantation. Uncontrolled portopulmonary hypertension may prevent or delay listing for transplant candidates, and the prognosis without treatment and ultimately transplant is extremely poor. We present a 29-year-old White woman, who had a post-liver transplant at infancy due to biliary atresia. Later on, she developed extensive portal vein thrombosis and portopulmonary hypertension and underwent a multivisceral transplant (liver, stomach, pancreaticoduodenal complex, and small and large intestine). Preoperative mean pulmonary artery pressure was <30 mm Hg with a pulmonary vascular resistance of <300 dynes^.s/cm⁵ on oral sildenafil and intravenous epoprostenol. Intraoperatively, management required comprehensive transfusion protocols, a careful balance between correcting blood loss and preventing thrombosis. Intravenous epoprostenol, sildenafil, milrinone, and inhaled nitric oxide were used to reduce elevated mean pulmonary artery pressure and right ventricular strain associated with vascular clamping, reperfusion, and massive fluid shifts. Nitric oxide and epoprostenol use unleashed antiplatelet effects on a patient already susceptible to coagulopathy. A multimodal and multidisciplinary approach continued throughout the surgery and in the postoperative period, which led to a successful outcome.

Mending the Model for End-Stage Liver Disease: An in-depth review of the past, present, and future portopulmonary hypertension Model for End-Stage Liver Disease exception

Patients with portopulmonary hypertension (POPH) have an increased cardiovascular and overall mortality risk when undergoing liver transplantation (LT). However, such risk is not captured in their Model for End-Stage Liver Disease (MELD) laboratory score. POPH MELD exception criteria were established in 2006 with the aim of prioritizing these patients for LT prior to pulmonary hypertension (PH) progression and eventual right heart failure. The original criteria emphasized a posttreatment, pre-LT mean pulmonary arterial pressure (mPAP) of <35 mm Hg and pulmonary vascular resistance (PVR) <400 dynes-s-cm^-5 or <5 Wood units (WU). Since 2006, there have been important advances in the treatment of POPH with pulmonary arterial hypertension (PAH)-targeted therapies and newer evidence regarding LT outcomes and risk factors for perioperative mortality. Specifically, PVR rather than mPAP has been shown to be more strongly associated with outcomes, including mortality. In addition, among treated patients with POPH, mPAP may be persistently elevated related to an elevated cardiac output or other factors that do not necessarily reflect POPH disease severity. Thus, in February 2021, the Organ Procurement and Transplantation Network approved proposed modifications to POPH MELD exception criteria, now allowing either of the following posttreatment, pre-LT hemodynamic profiles: mPAP less than 35 mm Hg and posttreatment PVR less than 400 dynes-s-cm^-5 (or less than 5 WU) or mPAP greater than or equal to 35 mm Hg and less than 45 mm Hg and posttreatment PVR less than 240 dynes-s-cm^-5 (or less than 3 WU). This article reviews the history of the POPH MELD exception criteria, describes the recent modifications to the exception criteria and the evidence supporting them, and highlights unanswered questions and areas for future research.

Evaluation of pulmonary arterial stiffness and comparison with right ventricular functions in patients with cirrhosis preparing for liver transplantation

OBJECTIVE

Pulmonary complications are common in patients with liver cirrhosis. Devolopment of pulmonary hypertension (PH) is associated with a poor prognosis in these patients. Pulmonary arterial stiffness (PAS) is considered an early sign of pulmonary vascular remodeling. The aim of this study is to investigate PAS and compare it with right ventricular (RV) functions in patients with cirrhosis who are scheduled for liver transplantation.

METHODS

The study included 52 cirrhosis patients (mean age 51.01 ± 12.18 years, male gender 76.9%) who were prepared for liver transplantation and 59 age and sex matched (mean age 51.28 ± 13.63 years, male gender 62.7%) healthy individuals. Patients with left ventricular ejection fraction (LVEF) less than 55%, ischemic heart disease, more than mild valvular heart disease, chronic pulmonary disease, congenital heart disease, rheumatic disease, moderate to high echocardiographic PH probability, rhythm or conduction disorders on electrocardiography were excluded from the study. In addition to conventional echocardiographic parameters, PAS value, pulmonary vascular resistance (PVR) and RV ejection efficiency was calculated by the related formulas with transthoracic echocardiography (TTE).

RESULTS

Demographic characteristics and cardiovascular risk factors of the groups were similar. PAS, PVR, and sPAP values were found to be significantly higher in the patient group (20.52 ± 6.52 and 13.73 ± 2.05; 1.43 ± 0.15 and 1.27 ± 0.14; 27.69 ± 3.91 and 23.37 ± 3.81 p < 0.001, respectively). RV FAC and RV Ee were significantly lower and RV MPI was significantly higher in the patient group (45.31 ± 3.85 and 49.66 ± 3.62, p < 0.001; 1.69 ± 0.35 and 1.85 ± 0.23, p = 0.005; 0.39 ± 0.07 and 0.33 ± 0.09, p = 0.001, respectively). PAS was significantly correlated with RV FAC and MPI (r = -0.423, p < 0.001; r = 0.301, p = 0.001, respectively).

CONCLUSIONS

Increased PAS in cirrhosis patients may be associated with early pulmonary vascular involvement. Evaluation of RV functions is important to determine the prognosis in these patients. FAC, MPI, and RV Ee measurements instead of TAPSE or RV S' may be more useful in demonstrating subclinical dysfunction. The correlation of PAS with RV FAC and MPI may indicate that RV subclinical dysfunction is associated with early pulmonary vascular remodeling in patients with liver cirrhosis.

Predictors of survival in portopulmonary hypertension: a 20-year experience

BACKGROUND AND OBJECTIVES

Portopulmonary hypertension (PoPH) is a rare complication of portal hypertension associated with poor survival. Scarce data is available on predictors of survival in PoPH with conflicting results. We sought to characterize the outcomes and variables associated with survival in a large cohort of patients with PoPH in an American population of patients.

STUDY DESIGN AND METHODS

We identified PoPH patients from the Cleveland Clinic Pulmonary Hypertension Registry between 1998 and 2019. We collected prespecified data, particularly focusing on hepatic and cardiopulmonary assessments and tested their effect on long-term survival.

RESULTS

Eighty patients with PoPH with a mean ± SD age of 54 ± 10 years, (54% females) were included in the analysis. The median Model for End-Stage Liver Disease with sodium (MELD-Na) score was 13.0 (10.0-18.0) at PoPH diagnosis. World Health Association functional class III-IV was noted in 57%. Mean pulmonary arterial pressure was 47 ± 10 mmHg and pulmonary vascular resistance 6.0 ± 2.8 Woods units. A total of 63 (78.5%) patients were started on pulmonary arterial hypertension (PAH)-specific treatment during the first 6 months of diagnosis. Survival rates at 1-, 3- and 5-year were 77, 52 and 34%, respectively. Cardiopulmonary hemodynamics as well as PAH-specific treatment did not affect survival. In the multivariable model, MELD-Na, resting heart rate and the presence of hepatic encephalopathy were independent predictors of survival.

CONCLUSION

PoPH patients have poor 5-year survival which is strongly associated to the severity of underlying liver disease and not to the hemodynamic severity of PoPH; therefore efforts should be focused in facilitating liver transplantation for these 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.

Outcomes of Liver Transplantation in Treated Portopulmonary Hypertension Patients With a Mean Pulmonary Arterial Pressure ≥35 mm Hg

Portopulmonary hypertension (POPH), pulmonary arterial hypertension (PAH) that develops in the setting of portal hypertension, affects 5%–6% of patients with liver disease and is associated with significant morbidity and mortality. A mean pulmonary arterial pressure (mPAP) threshold of 35 mm Hg is used to stratify perioperative risk and liver transplant eligibility in treated POPH patients but does not take into account the specific factors that contribute to the pressure elevation.

Sex Differences in Portopulmonary Hypertension

BACKGROUND

Portopulmonary hypertension (POPH), pulmonary arterial hypertension that develops in the setting of portal hypertension, can lead to right-sided heart failure and death. Being female is a known risk factor for POPH, but little is known about the effect of sex on clinical manifestations, hemodynamics, treatment response, and survival.

RESEARCH QUESTION

We sought to characterize sex differences in clinical characteristics, pulmonary hemodynamics, treatment response, and survival in patients with POPH.

STUDY DESIGN AND METHODS

We performed a retrospective cohort study of adult candidates for liver transplant (LT) who had POPH within the Organ Procurement and Transplantation Network database. Females and males were compared. Multivariate regression was performed to assess the association between sex and pulmonary vascular resistance (PVR) and survival. Patients were also stratified by age (50 years) to determine how age modifies the relationship between sex and hemodynamics and survival.

RESULTS

We included 190 adults (103 male, 87 female). Compared with men, women had a lower model for end-stage liver disease (MELD) score (12.1± 4.2 vs 13.8 ± 4.9; P = .01) and were more likely to have autoimmune liver disease. Women had a higher baseline PVR (610.6 ± 366.6 vs 461.0 ± 185.3 dynes-s-cm^-5; P < .001) and posttreatment PVR (244.6 ± 119.5 vs 202.0 ± 87.7 dynes-s-cm^-5; P = .008) and a greater treatment response (ΔPVR) (-359.3 ± 381.9 vs -260.2 ± 177.3 dynes-s-cm^-5; P = .03). In multivariate analysis, female sex (or gender) remained associated with a higher baseline PVR (P = .008). Women and men had overall similar survival (P > .05). When patients were stratified by age, being female was independently associated with worse waiting list survival after adjusting for MELD and PVR in younger patients (HR, 6.61; 95% CI, 1.25-35.08; P = .03) but not in older patients.

INTERPRETATION

Compared with male candidates, female candidates for LT who had POPH had a higher PVR and lower MELD score and were more likely to have autoimmune liver disease. Women and men had similar overall survival, but female sex (or gender) was associated with worse survival in younger patients.

Pulmonary Complications of Portal Hypertension

The most common pulmonary complications of chronic liver disease are hepatic hydrothorax, hepatopulmonary syndrome, and portopulmonary hypertension. Hepatic hydrothorax is a transudative pleural effusion in a patient with cirrhosis and no evidence of underlying cardiopulmonary disease. Hepatic hydrothorax develops owing to the movement of ascitic fluid into the pleural space. Hepatopulmonary syndrome and portopulmonary hypertension are pathologically linked by the presence of portal hypertension; however, their pathophysiologic mechanisms are significantly different. Hepatopulmonary syndrome is characterized by low pulmonary vascular resistance secondary to intrapulmonary vascular dilatations and hypoxemia; portopulmonary hypertension features elevated pulmonary vascular resistance and constriction/obstruction within the pulmonary vasculature.

Predictors of Waitlist Mortality in Portopulmonary Hypertension

BACKGROUND

The current Organ Procurement Transplantation Network policy grants Model for End-Stage Liver Disease (MELD) exception points to patients with portopulmonary hypertension (POPH), but potentially important factors, such as severity of liver disease and pulmonary hypertension, are not included in the exception score, and may affect survival. The purpose of this study was to identify significant predictors of waitlist mortality in patients with POPH.

METHODS

We performed a retrospective cohort study of patients in the Organ Procurement and Transplantation Network database with hemodynamics consistent with POPH (defined as mean pulmonary arterial pressure >25 mm Hg and pulmonary vascular resistance [PVR] ≥240 dynes·s·cm) who were approved for a POPH MELD exception between 2006 and 2014. Using a Cox proportional hazards model, we identified predictors of waitlist mortality (or removal for clinical deterioration).

RESULTS

One hundred ninety adults were included. Age (hazard ratio [HR], 1.04; 95% confidence interval [CI], 1.00-1.08; P = 0.0499), initial native MELD score (HR, 1.11; 95% CI, 1.05-1.17; P < 0.001), and initial PVR (HR, 1.12 per 100 dynes·s·cm; 95% CI, 1.02-1.23; P = 0.02) were the only significant univariate predictors of waitlist mortality and remained significant predictors in a multivariate model, which had a c-statistic of 0.71. PVR and mean pulmonary arterial pressure were not significant predictors of posttransplant mortality.

CONCLUSIONS

Both the severity of liver disease and POPH (as assessed by MELD and PVR, respectively) were significantly associated with waitlist, but not posttransplant, mortality in patients with approved MELD exceptions for POPH. Both factors should potentially be included in the POPH MELD exception score to more accurately reflect waitlist mortality risk.

Respiratory Complication in Liver Disease

Cirrhosis, the twelfth leading cause of death, accounts for 1.1% of all deaths in the United States. Although there are multiple pulmonary complications associated with liver disease, the most important complications that cause significant morbidity and mortality are hepatopulmonary syndrome, hepatic hydrothorax, and portopulmonary hypertension. Patients with cirrhosis who complain of dyspnea should be evaluated for these complications. This article reviews these complications.

International Liver Transplant Society Practice Guidelines: Diagnosis and Management of Hepatopulmonary Syndrome and Portopulmonary Hypertension

Two distinct pulmonary vascular disorders, hepatopulmonary syndrome (HPS) and portopulmonary hypertension (POPH) may occur as a consequence of hepatic parenchymal or vascular abnormalities. HPS and POPH have major clinical implications for liver transplantation. A European Respiratory Society Task Force on Pulmonary-Hepatic Disorders convened in 2002 to standardize the diagnosis and guide management of these disorders. These International Liver Transplant Society diagnostic and management guidelines are based on that task force consensus and should continue to evolve as clinical experience dictates. Based on a review of over 1000 published HPS and POPH articles identified via a MEDLINE search (1985-2015), clinical guidelines were based on, selected single care reports, small series, registries, databases, and expert opinion. The paucity of randomized, controlled trials in either of these disorders was noted. Guidelines are presented in 5 parts; I. Definitions/Diagnostic criteria; II. Hepatopulmonary syndrome; III. Portopulmonary hypertension; IV. Implications for liver transplantation; and V. Suggestions for future clinical research.

Comparison of Post-Liver Transplantation Outcomes in Portopulmonary Hypertension and Pulmonary Venous Hypertension: A Single-Center Experience

BACKGROUND

In potential liver transplant candidates, pulmonary vascular diseases, including portopulmonary hypertension (PoPH) and pulmonary venous hypertension (PVH), can be associated with high morbidity and mortality. Although there are clear guidelines regarding management and transplant listing criteria for patients with PoPH, the listing criteria for PVH are not well defined.

OBJECTIVE

The aim of this study was to describe and compare the perioperative and postoperative morbidity and mortality associated with PoPH and PVH in patients undergoing liver transplantation.

METHODS

We conducted a retrospective observational study of all patients referred for liver transplantation to our center between 2005 and 2015 who underwent a right heart catheterization (RHC) for screening for pulmonary hypertension as suggested by initial echocardiography. Based on the RHC data, the patients were grouped into no pulmonary hypertension (No PH), PoPH, and PVH categories. In patients who underwent liver transplantation, we recorded vital status intraoperatively and at 30 days and 1-year post-transplant, and we recorded the incidence of postoperative cardiopulmonary and renal complications.

RESULTS

Of the 134 patients who underwent RHC as part of the initial transplant evaluation, 50 patients were successfully transplanted. There was 1 intraoperative death in the PoPH group. No significant difference in mortality was noted between the No PH, PoPH, and PVH groups intraoperatively and 30 days after liver transplantation. At 1 year, the survival rates were 100%, 69.2%, and 94.1% in the No PH, PoPH, and PVH groups, respectively. With respect to cardiopulmonary and renal complications, no statistically significant difference was noted among the groups, though there was a trend toward increased post-transplant reversible pulmonary complications in the PVH group.

CONCLUSION

Our findings suggest that the post-transplant outcomes of patients with PoPH and PVH are similar. In light of the growing recognition of diastolic dysfunction and cirrhotic cardiomyopathy in decompensated cirrhotic patients at the time of transplant, the issue of pulmonary hypertension related to PVH will gain increasing importance as we assess these patients for transplantation. Therefore, future studies are needed to define evidence based guidelines to determine candidacy for liver transplantation in the context of PVH.

Anesthesia for Patients with Concomitant Hepatic and Pulmonary Dysfunction

Hepatic function and pulmonary function are interrelated with failure of one organ system affecting the other. With improved therapies, patients with concomitant hepatic and pulmonary failure increasingly enjoy a good quality of life and life expectancy. Therefore, the prevalence of such patients is increasing with more presenting for both emergent and elective surgical procedures. Hypoxemia requires a thorough evaluation in patients with end-stage liver disease. The most common etiologies respond to appropriate therapy. Portopulmonary hypertension and hepatopulmonary syndrome are associated with increased perioperative morbidity and mortality. It is incumbent on the anesthesiologist to understand the physiology of liver failure and its early effect on pulmonary function to ensure a successful outcome.

Current Approach to the Diagnosis and Management of Portopulmonary Hypertension

Portopulmonary hypertension (POPH) is a form of pulmonary arterial hypertension occurring in the setting of portal hypertension with or without hepatic cirrhosis. The presence of both portal and pulmonary vascular disease contributes to complicated hemodynamics and therapeutic challenges, though the severities do not appear to correlate directly. Diagnosis of POPH, and distinction from the commonly observed hyperdynamic state of end-stage liver disease, is typically accomplished with an initial screening transthoracic echocardiogram, followed by right heart catheterization for confirmation of hemodynamic parameters. Though few studies have directly evaluated use in POPH, pulmonary artery-directed therapy is the cornerstone of management, along with consideration of liver transplantation. Perioperative and long-term outcomes are variable, but uniformly worse in the setting of uncontrolled pulmonary pressures. Risk stratification and optimal patient selection for these interventions are areas of ongoing investigation.

[Portopulmonary hypertension: Updated review]

Portopulmonary hypertension (PPH) is a rare condition worldwide, although epidemiological data are unknown in Mexico. However, chronic liver diseases are very prevalent in Mexico. PPH is the 4th subtype in frequency in the group of pulmonary arterial hypertension. Its diagnosis is made within 2 scenarios: patients with suspected pulmonary hypertension and candidates for orthotopic liver transplantation (OLT). Both echocardiogram and a right cardiac catheterisation are crucial for diagnosis in both cases. PPH is a challenge for OLT, since it can significantly increase perioperative mortality. The use of specific therapy is the cornerstone of this disease, as a measure to improve the outcome of those who become candidates for OLT with moderate to severe PPH. It is important to recognise that PPH can be a contraindication to OLT. The role of lung-liver transplantation or heart-lung-liver transplantation as a measure to heal pulmonary vascular disease in patients with PPH is still uncertain.

Portopulmonary hypertension

Portopulmonary hypertension (PoPH) refers to the condition that pulmonary arterial hypertension (PAH) occur in the stetting of portal hypertension. The development of PoPH is thought to be independent of the severity of portal hypertension or the etiology or severity of liver disease. PoPH results from excessive vasoconstriction, vascular remodeling, and proliferative and thrombotic events within the pulmonary circulation that lead to progressive right ventricular failure and ultimately to death. Untreated PoPH is associated with a poor prognosis. As PoPH is frequently asymptomatic or symptoms are generally non-specific, patients should be actively screened for the presence of PoPH. Two-dimensional transthoracic echocardiography is a useful non-invasive screening tool, but a definitive diagnosis requires invasive hemodynamic confirmation by right heart catheterization. Despite a dearth of randomized, prospective data, an ever-expanding clinical experience shows that patients with PoPH benefit from therapy with PAH-specific medications including with endothelin receptor antagonists, phosphodiesterase-5 inhibitors, and/or prostanoids. Due to high perioperative mortality, transplantation should be avoided in those patients who have severe PoPH that is refractory to medical therapy.

From Child-Pugh to Model for End-Stage Liver Disease: Deciding Who Needs a Liver Transplant

This article reviews the historical evolution of the liver transplant organ allocation policy and the indications/contraindications for liver transplant, and provides an overview of the liver transplant evaluation process. The article is intended to help internists determine whether and when referral to a liver transplant center is indicated, and to help internists to counsel patients whose initial evaluation at a transplant center is pending.

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.

"Porto-pulmonary hypertension: a comprehensive review"

Porto-pulmonary hypertension (PoPH) is a rare but threatening vasculopathy, defined by the presence of pulmonary arterial hypertension (PAH) in the setting of portal hypertension. Although most commonly observed in cirrhotic patients, those with non-cirrhotic portal hypertension are also at risk of developing it. Little is known about the mechanisms by which PAH develop in patients with portal hypertension, but genetic factors, pulmonary vascular wall shear stress, and a dysregulation of vasoactive, proliferative and inflammatory mediators might be involved. PoPH is estimated to occur in 3 to 10% of patients with end-stage liver disease, although its frequency is not related to the severity of liver dysfunction or the degree of portal hypertension. Moderate-to-severe PoPH portends an extremely poor prognosis. Presentation is highly variable, therefore a high index of suspicion is required to establish the diagnosis. PoPH should be screened by transthoracic echocardiography (TTE) in cirrhotic patients presenting with dyspnoea as well as in all patients being evaluated for liver transplantation (LT) regardless of their symptoms. If TTE shows elevated pulmonary pressures, patients should undergo right heart catheterisation, which is required for the definitive diagnosis of PoPH. Without LT, the overall 5-year mortality in PoPH patients is 70%, but it should not be considered an indication for LT. Moderate-to-severe PoPH contraindicates LT, since it is associated with a prohibitively increased intra and postoperative mortality. However, there is now evidence supporting the use of PAH-specific therapies pre-LT in order to improve pulmonary haemodynamic measurements, so the procedure can then be performed with significantly lower risks.

Portopulmonary hypertension: an update

Portopulmonary hypertension represents a serious lung vascular disorder, defined as the presence of pulmonary arterial hypertension that is associated with portal hypertension, with or without the presence of significant liver disease. Transthoracic echocardiography represents the single best initial tool for the diagnostic evaluation in portopulmonary hypertension, and right heart catheterization remains the gold standard for definitive diagnosis. Despite the lack of randomized controlled trials in portopulmonary hypertension, some therapies have demonstrated improvements in cardiopulmonary haemodynamics and right ventricular function as described in case reports and case series. Specialists should be able to recognize indications and contraindications for liver transplantation in the setting of portopulmonary hypertension, and this review focuses on the appropriate diagnostic approach and current advances in medical therapies. Recognition of patients eligible for liver transplantation is needed to improve quality of life and survival.

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

Background. Little is known about the effect of pulmonary arterial hypertension (PAH) specific therapy on pulmonary hemodynamics and exercise capacity in patients with portopulmonary hypertension (PoPH) because such patients are usually excluded from randomized clinical trials (RCT) of such therapy. Methods. We searched PUBMED using the terms “(Therapy/Broad (filter)) AND (portopulmonary hypertension).” We included studies that met the following criteria: ≥5 patients, AND PoPH confirmed by right heart catheterization (RHC), AND follow-up RHC data, AND/OR baseline and follow-up 6MWD available. Results. 12 studies met our inclusion criteria. None was a RCT. The baseline mPAP was 48.6 ± 4.4 mmHg, cardiac output (CO) 5.6 ± 0.9 L/min, and pulmonary vascular resistance (PVR) 668.6 ± 219.1 dynes.sec/cm⁵. The baseline 6MWD was 348.2 ± 35.6 meters. The use of PAH specific therapy improved mPAP by 7.54 mmHg (95% CI 10.2 to 4.9), CO by 1.77 L/min (95% CI 1.1 to 2.4), and PVR by 253 dynes.sec/cm⁵ (95% CI 291.4 to 214.6) (n = 135) and 6MWD by 61.8 meters (95% CI 47.5 to 76) (n = 122). Conclusions. The use of PAH specific therapy in PoPH results in significant improvement in both pulmonary hemodynamics and 6MWD.

MELD exceptions for portopulmonary hypertension: current policy and future implementation

Since 2006, waitlist candidates with portopulmonary hypertension (POPH) have been eligible for standardized Model for End-Stage Liver Disease (MELD) exception points. However, there are no data evaluating the current POPH exception policy and its implementation. We used Organ Procurement and Transplantation Network (OPTN) data to compare outcomes of patients with approved POPH MELD exceptions from 2006 to 2012 to all nonexception waitlist candidates during this period. Since 2006, 155 waitlist candidates had approved POPH MELD exceptions, with only 73 (47.1%) meeting the formal OPTN exception criteria. Furthermore, over one-third of those with approved POPH exceptions either did not fulfill hemodynamic criteria consistent with POPH or had missing data, with 80% of such patients receiving a transplant based on receiving exception points. In multivariable multistate survival models, waitlist candidates with POPH MELD exceptions had an increased risk of death compared to nonexception waitlist candidates, regardless of whether they did (hazard ratio [HR]: 2.46, 95% confidence interval [CI]: 1.73-3.52; n = 100) or did not (HR: 1.60, 95% CI: 1.04-2.47; n = 55) have hemodynamic criteria consistent with POPH. These data highlight the need for OPTN/UNOS to reconsider not only the policy for POPH MELD exceptions, but also the process by which such points are awarded.

Portopulmonary hypertension

Portopulmonary hypertension (POPH) is the presence of pulmonary arterial hypertension in patients with portal hypertension. Among liver transplant (LT) candidates, reported incidence rates of POPH range from 4.5% to 8.5%. In patients with LT, intraoperative death and immediate post-LT mortality are feared clinical events when transplantation is attempted in the setting of untreated, moderate to severe POPH; therefore, POPH precludes LT unless the mean pulmonary artery pressure can be reduced to a safe level and right ventricular function optimized. Specific pulmonary artery vasodilator medications seem effective in reducing pulmonary artery pressures and improving right ventricular function and survival.

Pulmonary complications in chronic liver disease

The association of chronic liver disease with respiratory symptoms and hypoxia is well recognized. Over the last century, three pulmonary complications specific to chronic liver disease have been characterized: hepatopulmonary syndrome (HPS), portopulmonary hypertension (POPH), and hepatic hydrothorax (HH). The development of portal hypertension is fundamental in the pathogenesis of each of these disorders. HPS is the most common condition, found in 5%-30% of cirrhosis patients, manifested by abnormal oxygenation due to the development of intrapulmonary vascular dilatations. The presence of HPS increases mortality and impairs quality of life, but is reversible with liver transplantation (LT). POPH is characterized by development of pulmonary arterial hypertension in the setting of portal hypertension, and is present in 5%-10% of cirrhosis patients evaluated for LT. Screening for POPH in cirrhosis patients eligible for LT is critical since severe POPH is a relative contraindication for LT. Patients with moderate POPH, who respond adequately to medical therapy, may benefit from LT, although sufficient controlled data are lacking. HH is a transudative pleural effusion seen in 5%-10% of cirrhosis patients, in the absence of cardiopulmonary disease. Diagnosis of HH should prompt consideration for LT, which is the ultimate treatment for HH. Conservative management includes salt restriction and diuretics, with thoracentesis and transjugular intrahepatic portosystemic shunt (TIPS) as second-line therapeutic options.

Management of portopulmonary hypertension: New perspectives

Portopulmonary hypertension (PPHTN) is a known complication of cirrhosis. Moderate-to-severe PPHTN implies an extremely poor prognosis. It occurs in 5%-10% of patients referred for liver transplantation (LT), and probably with an higher incidence in patients with large portosystemic shunts. Patients with moderate-to-severe pulmonary hypertension have been previously excluded from LT because of the extremely high surgical risk and since the post-transplant outcome reported was poor. Recently, new perspectives in the management of patients with portopulmonary hypertension are emerging. In fact, some pulmonary vasoactive drugs have become routine in the treatment of patients with idiopathic pulmonary hypertension. These drugs, particularly epoprostenol, have been recently introduced in the treatment of patients with PPHTN, and have been shown to be effective in reducing pulmonary artery pressure as well as pulmonary vascular resistances. Furthermore, recent studies seem to demonstrate that treatment with pulmonary vasoactive drugs could allow liver transplantation with acceptable surgical risks and excellent survival. Although there are not large series nor prospective studies addressing this topic, the clinical scenario of patients with PPHTN seems to be positively changing.

Pulmonary contraindications, indications and MELD exceptions for liver transplantation: a contemporary view and look forward

Pulmonary concerns in liver transplant candidates have intraoperative and outcome implications. Evolving MELD exception policies address transplant priority for problems such as hepatopulmonary syndrome, portopulmonary hypertension, and hemorrhagic hereditary telangiectasia. Other pulmonary issues such as refractory hepatic hydrothorax, advanced chronic obstructive lung disease (including alpha-1 antitrypsin deficiency) and indeterminate pulmonary nodules may affect liver transplant consideration. Herein, we discuss current pulmonary-related contraindications, indications and MELD exception policies for liver transplantation, suggesting future considerations.

Pulmonary vascular complications in portal hypertension and liver disease: a concise review

Chronic liver disease and/or portal hypertension may be associated with one of the two pulmonary vascular complications: portopulmonary hypertension and hepatopulmonary syndrome. These pulmonary vascular disorders are notoriously underdiagnosed; however, they have a substantial negative impact on survival and require special attention in order to understand their diagnostic approach and to select the best therapeutic options. Portopulmonary hypertension results from excessive vasoconstriction, vascular remodeling, and proliferative and thrombotic events within the pulmonary circulation that lead to progressive right ventricular failure and ultimately to death. On the other hand, abnormal intrapulmonary vascular dilations, profound hypoxemia, and a wide alveolar-arterial gradient are the hallmarks of the hepatopulmonary syndrome, resulting in difficult-to-treat hypoxemia. The aim of this review is to summarize the latest pathophysiologic concepts, diagnostic approach, therapy, and prognosis of portopulmonary hypertension and hepatopulmonary syndrome, as well as to discuss the role of liver transplantation as a definitive therapy in selected patients with these conditions.

Preoperative Assessment and Management of Liver Transplant Candidates With Portopulmonary Hypertension

Pulmonary artery hypertension (PAH) that occurs as a consequence of portal hypertension is termed portopulmonary hypertension (POPH) and is associated with significant morbidity and mortality. Among liver transplant (LT) candidates, reported incidence rates of POPH range from 4.5% to 8.5%. The severity of POPH is unrelated to the severity of portal hypertension or the liver disease. In LT patients, intraoperative death and immediate post-LT mortality are feared clinical events when transplantation is attempted in the setting of untreated, moderate to severe POPH. Specific pulmonary artery vasodilator medications (PAH-specific therapy) appear effective in reducing pulmonary artery pressures, improving right ventricular (RV) function and survival. Thus, screening for and accurately diagnosing POPH prior to LT has become a standard of care. The post-LT course of patients with moderate POPH is unpredictable, but most patients can be weaned from PAH-specific therapy over time. In this article, we present an overview of the preoperative assessment of POPH with an emphasis on risk assessment for transplant and the most recent medical treatment options.

Review article: liver transplantation for the pulmonary disorders of portal hypertension

BACKGROUND

Liver transplantation is potentially a life-saving therapeutic intervention for patients with portopulmonary hypertension and hepatopulmonary syndrome. However, due to limited data, listing criteria for patients with these conditions have not been clearly established. Indeed, this has led some to speculate that transplantation may not be appropriate in cases of moderate-to-severe portopulmonary hypertension and severe hepatopulmonary syndrome.

AIM

To critically discuss the utility of LT for the treatment of hepatopulmonary syndrome and portopulmonary hypertension.

METHODS

A literature search was conducted in 2012 on PubMed, Ovid Embase, Ovid Medline and Scopus using the following search terms: hepatopulmonary syndrome, portopulmonary hypertension, pulmonary arterial hypertension, liver transplantation. Relevant manuscripts were included in the review.

RESULTS

Liver transplantation has established itself as an effective treatment for selected patients with hepatopulmonary syndrome and portopulmonary hypertension. A multidisciplinary team approach incorporating focused strategies (both pre- and post-operatively) aimed at improving oxygenation in patients with hepatopulmonary syndrome has led to a dramatic improvement in patient outcomes. Additionally, careful patient selection and the use of targeted pulmonary vascular therapies are successfully being used to treat portopulmonary hypertension and 'bridge' patients to successful liver transplantation.

CONCLUSIONS

Liver transplantation is an effective therapy for patients with hepatopulmonary syndrome and portopulmonary hypertension. However, rigorous screening and early identification of these conditions allied with aggressive pre-operative optimisation of physiology and diligent post-operative care are imperative to ensuring a good outcome.

Pulmonary vascular complications of liver disease

Hepatopulmonary syndrome and portopulmonary hypertension are two pulmonary vascular complications of liver disease. The pathophysiology underlying each disorder is distinct, but patients with either condition may be limited by dyspnea. A careful evaluation of concomitant symptoms, the physical examination, pulmonary function testing and arterial blood gas analysis, and echocardiographic, imaging, and hemodynamic studies is crucial to establishing (and distinguishing) these diagnoses. Our understanding of the pathobiology, natural history, and treatment of these disorders has advanced considerably over the past decade; however, the presence of either still increases the risk of morbidity and mortality in patients with underlying liver disease. There is no effective medical treatment for hepatopulmonary syndrome. Although liver transplantation can resolve hepatopulmonary syndrome, there appears to be worse survival even with transplantation. Liver transplantation poses a very high risk of death in those with significant portopulmonary hypertension, where targeted medical therapies may improve functional status and allow successful transplantation in a small number of select patients.

Shortness of breath in the patient with chronic liver disease

Shortness of breath is a common complaint in those with chronic liver disease. The differential diagnosis for this complaint includes primary pulmonary disorders, systemic disorders that affect the liver and lungs, and extrahepatic manifestations of portal hypertension. Orthotopic liver transplant, when appropriate, is the most effective therapy for many patients with dyspnea and chronic liver disease, although therapies to treat the underlying complications of cirrhosis may provide relief. Shortness of breath in patients with cirrhosis often portends a poor prognosis, and these patients should be evaluated for orthotopic liver transplant because this therapy is most likely to provide long-lasting benefit.

Management of pulmonary complications in pretransplant patients

This article addresses the most common pulmonary issues that affect liver transplant candidates. Pretransplant diagnostic criteria of these pulmonary problems in liver transplant patients are reviewed. Successful pulmonary management schemes and caveats are described. Risks for liver transplant are emphasized.

Successful outcomes following living donor liver transplantation for portopulmonary hypertension

Pulmonary arterial hypertension (PAH) associated with portal hypertension [portopulmonary hypertension (PPHTN)] occurs in 2% to 10% of patients with advanced liver disease and carries a very poor prognosis without treatment. Most hepatic transplantation centers consider moderate to severe PPHTN to be a contraindication to liver transplantation because of the high rate of perioperative complications. We present 3 patients with PPHTN who were managed with intravenous prostacyclin therapy followed by living donor liver transplantation (LDLT). These individuals demonstrated subsequent resolution of their pulmonary hypertension and were weaned off all PAH-specific medical therapy. We present their demographics, clinical courses, and hemodynamics. We discuss the potential indications for LDLT and risks with respect to this patient population. Limitations of the Model for End-Stage Liver Disease scoring system and outcome data for this patient population are reviewed. Future studies should be directed toward better defining indications for LDLT in patients with PPHTN, improving medicosurgical management, and assessing long-term outcomes.

Portopulmonary hypertension and right heart failure in patients with cirrhosis

PURPOSE OF REVIEW

In 5-6% of patients with portal hypertension a pathological state exists in which changes in the pulmonary vasculature cause an increase in pulmonary vascular resistance. The resultant increased work of the right ventricle may cause right heart failure and liver congestion. Patients with cirrhosis are at increased risk of mortality and transplant graft failure. The present review examines the latest advances in diagnosis, treatment and management of portopulmonary hypertension.

RECENT FINDINGS

Portopulmonary hypertension may be screened with transthoracic echocardiography and following up with a right heart catheterization in patients in whom the right ventricular systolic pressure is calculated to be 50 mmHg or greater. Therapy with prostanoids, endothelin-1 inhibitors and phosphodiesterase-5 inhibitors, or a combination of therapies, may be very effective in moderating pulmonary artery hypertension and, in selected patients, allowing liver transplantation to proceed safely. The model for end-stage liver disease (MELD) score is being weighted to accelerate responders on the waiting list for a transplant.

SUMMARY

Advances in diagnosis and therapy of portopulmonary hypertension allow patients with cirrhosis who respond to vasodilators to undergo liver transplantation safely. Unfortunately liver transplantation does not always result in reversal of pulmonary hypertension. There are now reports of de-novo pulmonary hypertension after liver transplantation.