Accuracy of Doppler echocardiography in the assessment of pulmonary hypertension in liver transplant candidates

[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.

[Diagnostic Algorithm and Screening of Pulmonary Hypertension]

The new guidelines for the diagnosis and treatment of pulmonary hypertension include a new diagnostic algorithm and provide specific recommendations for the required diagnostic procedures, including screening methods. These recommendations are commented on by national experts under the auspices of the DACH. These comments provide additional decision support and background information, serving as a further guide for the complex diagnosis of pulmonary hypertension.

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.

Evaluation of liver transplant candidates with non-alcoholic steatohepatitis

Non-alcoholic steatohepatitis (NASH) is anticipated to become the leading indication for liver transplantation (LT) in the United States in the near future. LT is indicated in patients with NASH-related cirrhosis who have medically refractory hepatic decompensation, synthetic dysfunction, and hepatocellular carcinoma (HCC) meeting certain criteria. The objective of LT evaluation is to determine which patient will derive the most benefit from LT with the least risk, thus maximizing the societal benefits of a limited resource. LT evaluation is a multidisciplinary undertaking involving several specialists, assessment tools, and diagnostic testing. Although the steps involved in LT evaluation are relatively similar across different liver diseases, patients with NASH-related cirrhosis have unique demographic and clinical features that affect transplant outcomes and influence their LT evaluation. LT candidates with NASH should be assessed for metabolic syndrome and obesity, malnutrition and sarcopenia, frailty, and cardiovascular disease. Interventions that treat cardiometabolic co-morbidities and improve patients' nutrition and functionality should be considered in order to improve patient outcomes in the waitlist and after LT.

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.

Doppler trans-thoracic echocardiography for detection of pulmonary hypertension in adults

BACKGROUND

Pulmonary hypertension (PH) is an important cause of morbidity and mortality, which leads to a substantial loss of exercise capacity. PH ultimately leads to right ventricular overload and subsequent heart failure and early death. Although early detection and treatment of PH are recommended, due to the limited responsiveness to therapy at late disease stages, many patients are diagnosed at a later stage of the disease because symptoms and signs of PH are nonspecific at earlier stages. While direct pressure measurement with right-heart catheterisation is the clinical reference standard for PH, it is not routinely used due to its invasiveness and complications. Trans-thoracic Doppler echocardiography is less invasive, less expensive, and widely available compared to right-heart catheterisation; it is therefore recommended that echocardiography be used as an initial diagnosis method in guidelines. However, several studies have questioned the accuracy of noninvasively measured pulmonary artery pressure. There is substantial uncertainty about the diagnostic accuracy of echocardiography for the diagnosis of PH.

OBJECTIVES

To determine the diagnostic accuracy of trans-thoracic Doppler echocardiography for detecting PH.

SEARCH METHODS

We searched MEDLINE, Embase, Web of Science Core Collection, ClinicalTrials.gov, World Health Organization International Clinical Trials Registry Platform from database inception to August 2021, reference lists of articles, and contacted study authors. We applied no restrictions on language or type of publication.

SELECTION CRITERIA

We included studies that evaluated the diagnostic accuracy of trans-thoracic Doppler echocardiography for detecting PH, where right-heart catheterisation was the reference standard. We excluded diagnostic case-control studies (two-gate design), studies where right-heart catheterisation was not the reference standard, and those in which the reference standard threshold differed from 25 mmHg. We also excluded studies that did not provide sufficient diagnostic test accuracy data (true-positive [TP], false-positive [FP], true-negative [TN], and false-negative [FN] values, based on the reference standard). We included studies that provided data from which we could extract TP, FP, TN, and FN values, based on the reference standard. Two authors independently screened and assessed the eligibility based on the titles and abstracts of records identified by the search. After the title and abstract screening, the full-text reports of all potentially eligible studies were obtained, and two authors independently assessed the eligibility of the full-text reports.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the risk of bias and extracted data from each of the included studies. We contacted the authors of the included studies to obtain missing data. We assessed the methodological quality of studies using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. We estimated a summary receiver operating characteristic (SROC) curve by fitting a hierarchical summary ROC (HSROC) non-linear mixed model. We explored sources of heterogeneity regarding types of PH, methods to estimate the right atrial pressure, and threshold of index test to diagnose PH. All analyses were performed using the Review Manager 5, SAS and STATA statistical software.

MAIN RESULTS

We included 17 studies (comprising 3656 adult patients) assessing the diagnostic accuracy of Doppler trans-thoracic echocardiography for the diagnosis of PH. The included studies were heterogeneous in terms of patient distribution of age, sex, WHO classification, setting, country, positivity threshold, and year of publication. The prevalence of PH reported in the included studies varied widely (from 6% to 88%). The threshold of index test for PH diagnosis varied widely (from 30 mmHg to 47 mmHg) and was not always prespecified. No study was assigned low risk of bias or low concern in each QUADAS-2 domain assessed. Poor reporting, especially in the index test and reference standard domains, hampered conclusive judgement about the risk of bias. There was little consistency in the thresholds used in the included studies; therefore, common thresholds contained very sparse data, which prevented us from calculating summary points of accuracy estimates. With a fixed specificity of 86% (the median specificity), the estimated sensitivity derived from the median value of specificity using HSROC model was 87% (95% confidence interval [CI]: 78% to 96%). Using a prevalence of PH of 68%, which was the median among the included studies conducted mainly in tertiary hospitals, diagnosing a cohort of 1000 adult patients under suspicion of PH would result in 88 patients being undiagnosed with PH (false negatives) and 275 patients would avoid unnecessary referral for a right-heart catheterisation (true negatives). In addition, 592 of 1000 patients would receive an appropriate and timely referral for a right-heart catheterisation (true positives), while 45 patients would be wrongly considered to have PH (false positives). Conversely, when we assumed low prevalence of PH (10%), as in the case of preoperative examinations for liver transplantation, the number of false negatives and false positives would be 13 and 126, respectively.

AUTHORS' CONCLUSIONS

Our evidence assessment of echocardiography for the diagnosis of PH in adult patients revealed several limitations. We were unable to determine the average sensitivity and specificity at any particular index test threshold and to explain the observed variability in results. The high heterogeneity of the collected data and the poor methodological quality would constrain the implementation of this result into clinical practice. Further studies relative to the accuracy of Doppler trans-thoracic echocardiography for the diagnosis of PH in adults, that apply a rigorous methodology for conducting diagnostic test accuracy studies, are needed.

Cardiovascular manifestation of end-stage liver disease and perioperative echocardiography for liver transplantation: anesthesiologist’s view

Liver transplantation (LT) is the curative therapy for decompensated cirrhosis. However, anesthesiologists can find it challenging to manage patients undergoing LT due to the underlying pathologic conditions of patients with end-stage liver disease and the high invasiveness of the procedure, which is frequently accompanied by massive blood loss. Echocardiography is a non-invasive or semi-invasive imaging tool that provides real-time information about the structural and functional status of the heart and is considered to be able to improve outcomes by enabling accurate and detailed assessments. This article reviews the pathophysiologic changes of the heart accompanied by cirrhosis that mainly affect hemodynamics. We also present a comparative review of the diagnostic criteria for cirrhotic cardiomyopathy published by the World Congress of Gastroenterology in 2005 and the Cirrhotic Cardiomyopathy Consortium in 2019. This article discusses the conditions that could affect hemodynamic stability and postoperative outcomes, such as coronary artery disease, left ventricular outflow tract obstruction, portopulmonary hypertension, hepatopulmonary syndrome, pericardial effusion, cardiac tamponade, patent foramen ovale, and ascites. Finally, we cover a number of intraoperative factors that should be considered, including intraoperative blood loss, rapid reaccumulation of ascites, manipulation of the inferior vena cava, post-reperfusion syndrome, and adverse effects of excessive fluid infusion and transfusion. This article aimed to summarize the cardiovascular manifestations of cirrhosis that can affect hemodynamics and can be evaluated using perioperative echocardiography. We hope that this article will provide information about the hemodynamic characteristics of LT recipients and stimulate more active use of perioperative echocardiography.

Preoperative 2D-echocardiographic assessment of pulmonary arterial pressure in subgroups of liver transplantation recipients

BACKGROUND

The clinical efficacy of preoperative 2D-echocardiographic assessment of pulmonary arterial pressure (PAP) has not been evaluated fully in liver transplantation (LT) recipients.

METHODS

From October 2010 to February 2017, a total of 344 LT recipients who underwent preoperative 2D-echocardiography and intraoperative right heart catheterization (RHC) was enrolled and stratified according to etiology, disease progression, and clinical setting. The correlation of right ventricular systolic pressure (RVSP) on preoperative 2D-echocardiography with mean and systolic PAP on intraoperative RHC was evaluated, and the predictive value of RVSP > 50 mmHg to identify mean PAP > 35 mmHg was estimated.

RESULTS

In the overall population, significant but weak correlations were observed (R = 0.27; P < 0.001 for systolic PAP, R = 0.24; P < 0.001 for mean PAP). The positive and negative predictive values of RVSP > 50 mmHg identifying mean PAP > 35 mmHg were 37.5% and 49.9%, respectively. In the subgroup analyses, correlations were not significant in recipients of deceased donor type LT (R = 0.129; P = 0.224 for systolic PAP, R = 0.163; P = 0.126 for mean PAP) or in recipients with poorly controlled ascites (R = 0.215; P = 0.072 for systolic PAP, R = 0.21; P = 0.079 for mean PAP).

CONCLUSIONS

In LT recipients, the correlation between RVSP on preoperative 2D-echocardiography and PAP on intraoperative RHC was weak; thus, preoperative 2D-echocardiography might not be the optimal tool for predicting intraoperative PAP. In LT candidates at risk of pulmonary hypertension, RHC should be considered.

Ultrasonography in the diagnosis of complications in patients with portal hypertension

This review focuses on ultrasonography (US) to diagnose patients with complications in portal hypertension. Clinicians first use US to evaluate patients with suspected portal hypertension, because US is quick, simple, and radiation free. US is necessary for grading and performing paracentesis for ascites. Doppler US-based detection of reverse splanchnic vein flow or the presence of a spontaneous portosystemic shunt is highly specific in patients with cirrhosis. Since it is important to estimate spleen size in patients with portal hypertension, spleen size is usually measured by US. Spleen volume can be more accurately measured with 3D-US. Estimation of viable residual splenic volume after partial splenic embolization should be limited to cases with total splenic volume less than 1000 ml. Portal vein thrombosis is often detected during the US examination performed when symptoms first appear or during the follow-up. Two-dimensional transthoracic echocardiography is an excellent noninvasive screening test in patients with pulmonary portal hypertension who can undergo it. By measuring the maximum and minimum diastolic blood flow velocities in the renal arteries using renal color Doppler US, the pulsatility index (PI) and resistive index (RI) can be calculated. The PI and RI in cirrhotic patients were significantly higher than those in healthy subjects and patients with chronic hepatitis, and showed a significant positive correlation with the Child-Pugh Score. In conclusion, US is an essential tool for the diagnosis and treatment of patients with portal hypertension.

Clinical impact of mild to moderate pulmonary hypertension in living-donor liver transplantation

Severe pulmonary hypertension (PHT) is a contraindication to liver transplantation (LT); however, the prognostic implication of mild to moderate PHT in living-donor LT (LDLT) is unknown. The study cohort retrospectively included 1307 patients with liver cirrhosis who underwent LDLT. PHT was defined as a mean pulmonary artery pressure (PAP) of ≥25 mmHg, measured intraoperatively just before surgery. The primary endpoint was graft failure within 1 year after LDLT, including retransplantation or death from any cause. The secondary endpoints were in-hospital adverse events. In the overall cohort, the median Model for End-stage Liver Disease-Sodium (MELD-Na) score was 19, and 100 patients (7.7%) showed PHT. During 1-year follow-up, graft failure occurred in 94 patients (7.2%). Patients with PHT had lower 1-year graft survival (86% vs. 93.4%, P = 0.005) and survival rates (87% vs. 93.6%, P = 0.011). Mean PAP was associated with a high risk of in-hospital adverse events and 1-year graft failure. Adding the mean PAP to the clinical risk model improved the risk prediction. In conclusion, mild to moderate PHT was associated with higher risks of 1-year graft failure and in-hospital events, including mortality after LDLT in patients with liver cirrhosis. Intraoperative mean PAP can help predict the early clinical outcomes after LDLT.

Accuracy of echocardiographically estimated pulmonary artery pressure in dogs with myxomatous mitral valve disease

INTRODUCTION

Echocardiographically identified pulmonary hypertension is an independent predictor of poor outcome in dogs affected by myxomatous valvular degeneration (MMVD). Systolic pulmonary arterial pressure is routinely estimated based on its relationship with the Doppler-determined velocity of tricuspid regurgitation as defined by the simplified Bernoulli equation (sPAP_D). Experimental studies suggest that the method is imperfect, but its accuracy in dogs with MMVD is not known.

ANIMALS

Twenty dogs affected by MMVD that had cardiac remodeling and measurable tricuspid regurgitation.

METHODS

A flow-directed thermodilution monitoring catheter was percutaneously placed in the right external jugular vein and advanced to the main pulmonary artery. Pulmonary arterial systolic pressure was recorded (systolic pulmonary arterial pressure obtained by right heart catheterization [sPAP_C]). A second operator contemporaneously acquired tricuspid regurgitant velocity spectra to calculate sPAP_D. Each operator was blinded to the result of the other techniques.

RESULTS

Technical difficulties prevented the analysis of catheterization data in two dogs. Eighteen measurement pairs were therefore used for comparison of sPAP_C and sPAP_D through correlation and Bland-Altman analysis. A statistically significant bias between sPAP_C and sPAP_D (mean difference = 0.5 mmHg; confidence interval = -6.5 mmHg, +7.5 mmHg) was not detected. The interval of agreement between the techniques was wide (-27.3 mmHg, +28.2 mmHg). A significant linear association between the two techniques was not identified (r = 0.11, p=0.17).

CONCLUSION

Echocardiographically estimated pulmonary artery pressure poorly agrees with sPAP_C measurement in dogs affected by MMVD and cardiac remodeling with or without previously diagnosed congestive heart failure. In these dogs, sPAP_D could under- or over-estimate sPAP_C by more than 20 mmHg, and therefore caution should be used when interpreting sPAP_D.

Pulmonary Complications in Candidates for Liver Transplantation

The liver plays a pivotal role in maintaining the homeostasis of various organ systems. Also, end-stage liver disease and its complications are major causes of morbidity and mortality among adults. Individuals who develop a chronic liver disease are at increased risk of progression to multi-organ dysfunction, including the pulmonary system. The clinical complications of pulmonary problems related to the presence of liver disease range from mild (such as hypoxemia) to life-threatening diseases (such as portopulmonary hypertension and hepatopulmonary syndrome). Herein, the major pulmonary complications related to liver cirrhosis and considerations for performing liver transplantation are reviewed.

Clinical Outcomes after Liver Transplantation in Patients with Portopulmonary Hypertension

BACKGROUND

Portopulmonary hypertension (POPH) is the presence of pulmonary arterial (PA) hypertension in patients with portal hypertension and is associated with significant morbidity and mortality. In a cohort of POPH patients, we describe the clinical outcomes of POPH patients who underwent liver transplantation (LT).

METHODS

Retrospectively collected data from a prospectively assembled cohort of all consecutive POPH adults evaluated in three transplant centers from 1996 to 2019.

RESULTS

From a cohort of 228 POPH patients, 50 patients underwent LT. Significant hemodynamic improvement after PA-targeted therapy was observed, with 58% receiving only monotherapy pre-transplant. After LT, 21 (42%) patients were able to discontinue and remained off PA-targeted therapy. The 1, 3, and 5 year unadjusted survival rates after LT were 72%, 63% and 60%, respectively. An elevated pulmonary vascular resistance (PVR) before LT was associated with worse survival rate (HR 1.91, 95% CI 1.07-3.74, p=0.04). No survival difference was observed in those granted MELD exception or transplants performed before or after the year 2010.

CONCLUSION

Significant number of POPH patients discontinued PA-targeted therapy after LT. Higher PVR before LT was associated with worse survival, as was monotherapy use. Despite effective PA-targeted therapies, POPH survival outcomes after LT in our cohort were modest and may reflect the need for more aggressive therapy.

Performance of echocardiography for detection of portopulmonary hypertension among liver transplant candidates: Meta-analysis

BACKGROUND

Evaluation of pulmonary arterial pressure is crucial among cirrhotic patients, considering that moderate portopulmonary hypertension (POPH) is a contraindication for liver transplantation. Although right heart catheterization (RHC) is the most accurate method to diagnose POPH, it is invasive.

OBJECTIVE

The aim of the study is to evaluate the performance of echocardiography in detecting POPH in liver transplant candidates.

METHODS

A Literature search was performed, and pooled sensitivity, specificity, positive likelihood ratio (LR), negative LR, and area under the summary receiver operating curve (AUC) were calculated. Subgroup analyses were performed based on different cutoff values for echocardiography and diagnostic criteria of RHC.

RESULTS

Sensitivity, specificity, positive LR, negative LR, and AUC of echocardiography for detection of POPH were 0.86 (0.74, 0.94), 0.87 (0.84, 0.90), 7.17 (3.59, 14.31), 0.22 (0.13, 0.38), and 0.807 while they were 0.82 (0.74, 0.89), 0.81 (0.78, 0.84), 117.75 (16.03, 865.08), 0.28 (0.16, 0.50), and 0.876for detection of moderate POPH, respectively. Performance of echocardiography was not significantly different in the subgroup analyses of stringency of POPH criteria and pulmonary arterial systolic pressure (ePASP) cutoffs.

CONCLUSIONS

Our meta-analysis supports utilization of echocardiography for screening of POPH. However, RHC remains essential in highly suspicious cases. Echocardiographic data other than ePASP should be evaluated in future studies.

Pulmonary Complications in Patients with Liver Cirrhosis

Patients with advanced chronic liver diseases, particularly with decompensated liver cirrhosis, can develop specific pulmonary complications independently of any pre-existing lung disease. Especially when dyspnea occurs in combination with liver cirrhosis, patients should be evaluated for hepato-pulmonary syndrome (HPS), porto-pulmonary hypertension (PPHT), hepatic hydrothorax and spontaneous bacterial empyema, which represent the clinically most relevant pulmonary complications of liver cirrhosis. Importantly, the pathophysiology, clinical features, diagnosis and the corresponding therapeutic options differ between these entities, highlighting the role of specific diagnostics in patients with liver cirrhosis who present with dyspnea. Liver transplantation may offer a curative therapy, including selected cases of HPS and PPHT. In this review article, we summarize the pathogenesis, clinical features, diagnostic algorithms and treatment options of the 4 specific pulmonary complications in patients with liver cirrhosis.

Hepatopulmonary Syndrome and Portopulmonary Hypertension: Current Status and Implications for Liver Transplantation

PURPOSE OF REVIEW

Hepatopulmonary syndrome (HPS) and portopulmonary hypertension (PoPH) are both pulmonary vascular complications of advanced liver disease; however, these syndromes have distinct pathophysiology, clinical implications, and management.

RECENT FINDINGS

While both conditions are associated with portal hypertension, HPS results from diffuse pulmonary capillary vasodilation and PoPH results from vasoconstriction and vascular remodeling of pulmonary arteries. In HPS, no medical therapies clearly improve outcomes; however, patients have excellent post-LT outcomes with near uniform reversal of hypoxemia. In PoPH, several medical therapies used in idiopathic pulmonary hypertension have been shown improve pulmonary hemodynamics, symptoms, and potentially LT outcomes; however, further study is needed to determine best treatment regimens, long-term outcomes on medical therapy, and role of LT.

SUMMARY

While HPS results in severe hypoxemia that is usually reversible by LT, PoPH patients develop progressive pulmonary hypertension that may improve with medical therapy.

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.

Diagnostic accuracy of transthoracic echocardiography for pulmonary hypertension: a systematic review and meta-analysis

OBJECTIVE

To evaluate the diagnostic accuracy of transthoracic echocardiography (TTE) in patients with pulmonary hypertension (PH).

DESIGN

Systematic review and meta-analysis.

DATA SOURCES AND ELIGIBILITY CRITERIA

Embase, Cochrane Library for clinical trials, PubMed and Web of Science were used to search studies from inception to 19 June, 2019. Studies using both TTE and right heart catheterisation (RHC) to diagnose PH were included.

MAIN RESULTS

A total of 27 studies involving 4386 subjects were considered as eligible for analysis. TTE had a pooled sensitivity of 85%, a pooled specificity of 74%, a pooled positive likelihood ratio of 3.2, a pooled negative likelihood ratio of 0.20, a pooled diagnostic OR of 16 and finally an area under the summary receiver operating characteristic curve of 0.88. The subgroup with the shortest time interval between TTE and RHC had the best diagnostic effect, with sensitivity, specificity and area under the curve (AUC) of 88%, 90% and 0.94, respectively. TTE had lower sensitivity (81%), specificity (61%) and AUC (0.73) in the subgroup of patients with definite lung diseases. Subgroup analysis also showed that different thresholds of TTE resulted in a different diagnostic performance in the diagnosis of PH.

CONCLUSION

TTE has a clinical value in diagnosing PH, although it cannot yet replace RHC considered as the gold standard. The accuracy of TTE may be improved by shortening the time interval between TTE and RHC and by developing an appropriate threshold. TTE may not be suitable to assess pulmonary arterial pressure in patients with pulmonary diseases.

PROSPERO REGISTRATION NUMBER

PROSPERO CRD42019123289.

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.

The efficacy of serum brain natriuretic peptide for the early detection of portopulmonary hypertension in biliary atresia patients before liver transplantation

Severe portopulmonary hypertension (POPH) is a contraindication for liver transplantation (LT) because of the high risk of postoperative heart failure. The early detection of POPH is important for patients with biliary atresia (BA). Brain natriuretic peptide (BNP) is known to be correlated with liver fibrosis in patients with liver cirrhosis. The aim of this study was to elucidate the efficacy of BNP measurement for the follow-up of patients with BA. Thirty-two patients with BA were identified from September 2011 to December 2016. As indices of liver fibrosis/cirrhosis, APRI (P < .0001), FIB-4 (P < .0001), Child-Pugh score (P < .0001), IV collagen (P = .0005), and hyaluronic acid (P = .0291) had high or moderate correlations with BNP. Patients with splenomegaly, esophageal varices, liver fibrosis, and collateral veins had significantly higher BNP levels than those without. Patients diagnosed with POPH had significantly higher BNP levels in comparison with those patients without (P = .0068). In contrast, PELD/MELD scores showed an almost negligible correlation with the BNP level. LT was successful in 3 asymptomatic BA patients with POPH who had high BNP levels despite the low PELD/MELD scores. In conclusion, routine serum BNP surveillance can be easy to predict asymptomatic POPH. This may help to identify POPH before it reaches a stage that would contraindicate LT.

Correlation between Echocardiographic Pulmonary Artery Pressure Estimates and Right Heart Catheterization Measurement in Liver Transplant Candidates

BACKGROUND

Patients undergoing liver transplant have worse outcomes in the presence of pulmonary hypertension. Correlation between echocardiography and catheterization derived pressures in this population is not well studied. Our study's aim is to show the relationship between pulmonary artery systolic pressure derived from transthoracic echo (ePASP) with pulmonary artery systolic pressure measured during right heart catheterization (cPASP).

METHODS

Single center retrospective study, patients being evaluated for liver transplant (n = 31) who had an interpretable Doppler signal for ePASP and had right heart catheterization (RHC) measurements within 3 months constituted the study group. Control group (n = 49) consisted of patients who did not have liver disease.

RESULTS

There was modest correlation between ePASP and cPASP (R = 0.58, p < 0.001) in LT candidates (n = 31) compared with the control group (R = 0.74, p < 0.001, n = 49). The 95% limits of agreement by Bland-Altman analysis ranged from +33.6 mmHg to -21.7 mmHg. Using receiver operating characteristic analysis, ePASP cut-off > 47 mmHg was 59% sensitive and 78% specific to diagnose pulmonary artery (PA) hypertension (mean PA pressure > 25 mmHg) in the LT candidates, while a similar cutoff performed well in the control group (cutoff > 43 mmHg, n = 47, 91% sensitive, 100% specific).

CONCLUSIONS

Compared with other disease states, ePASP correlates modestly with cPASP in patients with advanced liver disease. A higher ePASP cutoff should be used to screen for pulmonary hypertension. A multi-center prospective study with simultaneous transthoracic echocardiography and RHC measurements is required to determine the best cut-off in this population.

Perioperative Care of the Liver Transplant Patient

With the evolution of surgical and anesthetic techniques, liver transplantation has become "routine," allowing for modifications of practice to decrease perioperative complications and costs. There is debate over the necessity for intensive care unit admission for patients with satisfactory preoperative status and a smooth intraoperative course. Postoperative care is made easier when the liver graft performs optimally. Assessment of graft function, vigilance for complications after the major surgical insult, and optimization of multiple systems affected by liver disease are essential aspects of postoperative care. The intensivist plays a vital role in an integrated multidisciplinary transplant team.

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.

Pulmonary hypertension in patients with hepatic cirrhosis and portal hypertension. An echographic study

Aim of the study

The aim of the study is to determine the frequency of pulmonary hypertension in patients with hepatic cirrhosis and portal hypertension, to determine the possibility of an accurate ultrasound diagnosis of the characteristics of this complication.

Method

347 patients with liver cirrhosis consecutively hospitalized at Coltea Clinical Hospital were screened. 61 were excluded because of other possible causes of portal or pulmonary hypertension. All patients were investigated clinically and by abdominal and cardiac ultrasonography.

Results

Of the remaining 286 patients, 116 had portal hypertension, 27 of them (23%) having pulmonary hypertension. In this group we found a higher cardiac index and right atrial volume, higher pressures in the right atrium, suggesting a hyperdynamic state. Porto-pulmonary hypertension was found in only one patient.

Conclusion

Echocardiography permits characterization of patients with cirrhosis and portal hypertension

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.

Pulmonary Hypertension Improves After Orthotopic Liver Transplant in Patients With Chronic Liver Disease

OBJECTIVES

Pulmonary hypertension is a common finding in chronic liver disease patients that has prognostic significance. In this study, we aimed to evaluate the prevalence and severity of pulmonary hypertension in patients undergoing orthotopic liver transplant. We also evaluated pulmonary artery pressure changes after transplant surgery.

MATERIALS AND METHODS

The records of adult patients with chronic liver disease who underwent orthotopic liver transplant at our center between 2004 and 2015 were retrospectively evaluated. Clinical and demographic variables and laboratory data were noted. Transthoracic Doppler echocardiographic examination reports were obtained. Using continuous-wave Doppler examination, systolic pulmonary artery pressure values were calculated. Pulmonary hypertension was defined as systolic pulmonary artery pressure ≥ 30 mm Hg. Among 208 adult patients who underwent orthotopic liver transplant, 203 who had Doppler echocardiographic examination were enrolled.

RESULTS

The mean age of patients was 42.1 ± 14.1 years (range, 16-67 y), and 143 (70.4%) were men. During preoperative assessment, pulmonary hypertension was identified in 47 patients (23.2%), of whom 10 displayed systolic pulmonary artery pressure > 50 mm Hg. Compared with preoperative values of systolic pulmonary artery pressure (46.8 ± 8.4 mm Hg), a significant reduction in mean values (to 39.3 ± 13.3 mm Hg) was observed postoperatively (P = .007).

CONCLUSIONS

The findings of this study indicate that pulmonary hypertension is a common finding in adult chronic liver disease patients undergoing orthotopic liver transplant. A significant improvement occurs in systolic pulmonary artery pressure values following transplant surgery. Regarding the prevalence and prognostic significance of pulmonary hypertension, all patients with chronic liver disease should be evaluated with transthoracic Doppler echocardiography before transplant.

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.

Portopulmonary hypertension in liver transplant candidates

Pulmonary vascular disorders including portopulmonary hypertension (PoPHT) are among the common complications of liver disease and are prognostically significant. Survival is very low without medical treatment and liver transplantation. With advances in medical therapy for elevated pulmonary artery pressure (PAP) and liver transplant surgery, survival of patients with PoPHT and advanced liver disease is significantly improved. Because of the prognostic significance of PoPHT and the limited donor pool, a comprehensive preoperative cardio-pulmonary assessment is of great importance in cirrhotic patients prior to transplant surgery. Therefore, a detailed transthoracic Doppler echocardiographic examination must be an essential component of this evaluation. Patients with mild PoPHT can safely undergo liver transplant surgery. In cases of moderate to severe PoPHT, right heart catheterization (RHC) should be performed. In patients with moderate to severe PoPHT on RHC (mean PAP 35-45 mmHg), vasodilator therapy should be attempted. Liver transplantation should be encouraged in cases that demonstrate a positive response. Bridging therapy with specific pulmonary arterial hypertension treatment agents should be considered until the transplant surgery and should be continued during the peri- and post-operative periods as needed.

Intrapulmonary vascular dilatations are common in portopulmonary hypertension and may be associated with decreased survival

Hepatopulmonary syndrome (HPS) and portopulmonary hypertension (POPH) are pulmonary vascular complications of portal hypertension with divergent clinicopathologic features and management. The presence of intrapulmonary vascular dilatations (IPVDs), detected by agitated saline contrast-enhanced transthoracic echocardiography (cTTE), is an essential feature of HPS but is not typically characteristic of POPH. Although IPVDs have been reported rarely in POPH, the prevalence and significance of this finding have not been systematically studied. We conducted a retrospective chart review of 80 consecutive patients diagnosed with POPH from January 1, 2002 to June 30, 2014 with documentation of cTTE findings, pulmonary hemodynamics, oxygenation, and survival. A total of 34 of the 80 patients (42%) underwent cTTE during initial diagnosis of POPH. IPVDs were detected in 20/34 patients (59%); intracardiac shunting was detected in 9/34 patients (26%; 4 also had IPVDs); and 9 patients (26%) had negative cTTE with no evidence of IPVD or intracardiac shunting. Patients with IPVD had decreased survival as compared to those without IPVD (P = 0.003), a trend that persisted after exclusion of liver transplant recipients (P =  0.07). The IPVD group had a trend toward higher Model for End-Stage Liver Disease score with and without incorporating sodium (MELD or MELD-Na; P = 0.05 for both). The right ventricular index of myocardial performance (RIMP) was lower in the IPVD group (median, 0.4 versus 0.6; P = 0.006). Patients with moderate or large IPVDs (n = 6) had worse oxygenation parameters (partial pressure of arterial oxygen, diffusing capacity of the lung for carbon monoxide, and alveolar-arterial oxygen gradient) as compared to the rest of the cohort. Unexpectedly, IPVDs were frequently documented in POPH and associated with decreased survival. To further understand this observation, we recommend screening for IVPD in all patients with POPH.

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.

Correlation between Pulmonary Artery Pressure Measured by Echocardiography and Right Heart Catheterization in Patients with Rheumatic Mitral Valve Stenosis (A Prospective Study)

INTRODUCTION

Right heart catheterization (RHC) remains the gold standard for hemodynamic assessment of the right heart and pulmonary artery. However, this is an invasive tool, and noninvasive alternatives such as transthoracic echocardiography (TTE) are preferable. Nonetheless, the correlation between measurements by TTE and RHC are debated. In this study, we prospectively examined the correlation between systolic and mean pulmonary artery pressures (sPAP and mPAP) measured by RHC and TTE in patients with hemodynamically significant rheumatic mitral stenosis (MS).

MATERIAL AND METHODS

Three hundred patients with hemodynamically significant MS undergoing TTE who were scheduled to undergo RHC within 24 hours were analyzed. PAP measurements were taken for all patients by RHC (sPAP(RHC), mPAP(RHC)). Maximum velocity of tricuspid regurgitation (TR) jet obtained by continuous-wave Doppler with adding right atrial (RA) pressure was used for measuring sPAP by TTE (sPAP(TRVmax)). Mean PAP was measured using either pulmonary artery acceleration time (mPAP(PAAT)) method or by adding RA pressure to velocity-time integral of TR jet (mPAP(TRVTI)).

RESULTS

A good correlation between sPAP(RHC) and sPAP(TRVmax) (r = 0.89, P < 0.001), between mPAP(RHC) and mPAP(PAAT) (r = 0.9, P < 0.001), and between mPAP(RHC) and mPAP(TRVTI) (r = 0.92, P < 0.001) was found. Sensitivity and specificity of sPAP(TRV) max in detecting pulmonary hypertension (PH) were 92.8% and 86.6% and of mPAP(PAAT) were 94.1% and 73.3%, respectively.

CONCLUSION

The noninvasive assessment of sPAP and mPAP by TTE correlates well with invasive measurements and has an acceptable specificity and sensitivity in detecting PH in patients with hemodynamically significant MS.

Hepatopulmonary syndrome and portopulmonary hypertension: recent knowledge in pathogenesis and overview of clinical assessment

Hepatopulmonary syndrome and portopulmonary hypertension are cardiopulmonary complications, which are not infrequently seen in patients with liver disease and/or portal hypertension. These entities are both clinically and pathophysiologically different: the hepatopulmonary syndrome is characterized by abnormal pulmonary vasodilation and right-to-left shunting resulting in gas exchange abnormalities, whereas portopulmonary hypertension is caused by pulmonary artery vasoconstriction leading to hemodynamic failure. As both hepatopulmonary syndrome and portopulmonary hypertension are associated with significantly increased morbidity and mortality, and as these patients are commonly asymptomatic, all liver transplantation candidates should be actively screened for the presence of these two complications. The aim of is this review is to provide an overview on the hepatopulmonary syndrome and portopulmonary hypertension with primary focus on diagnosis and recent knowledge regarding pathogenesis and therapeutic targets.

"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.

Thrombocytopenia is an independent predictor of mortality in pulmonary hypertension

BACKGROUND

Established prognostic factors for pulmonary hypertension (PH) include brain natriuretic peptide, troponins and hemodynamic measures such as central venous pressure and cardiac output. The prognostic role of thrombocytopenia, however, has yet to be determined in patients with PH. The aim of this study was to evaluate effect of thrombocytopenia on mortality in patients with PH.

METHODS

521 patients with severe PH, defined by a pulmonary artery systolic pressure >60 mm Hg on transthoracic echocardiography and a platelet count measured within one month after diagnosis were enrolled from three hospitals of Montefiore Medical Center. The cohort was divided into two groups: mild thrombocytopenia to a normal platelet count (platelet count 100,000-450,000 per uL); and moderate to severe thrombocytopenia (platelet count <100,000 per uL). Inpatient and social security death records were used to determine 1-year all-cause mortality.

RESULTS

Mean age was 70.3 ± 15.6 with 40% of patients being male. Overall mortality at 1 year was 30.7%, with increased mortality in PH patients with mild thrombocytopenia compared to those with moderate to severe thrombocytopenia (46.5% vs. 27.0%, p < 0.001). In multivariate analysis, moderate to severe thrombocytopenia remained an independent predictor of mortality (HR 1.798, 95% CI 1.240-2.607, p = 0.002).

CONCLUSIONS

Moderate to severe thrombocytopenia is an independent predictor of higher mortality in patients with severe PH. These findings may support the use of thrombocytopenia as a useful prognostic indicator in patients with severe PH.

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.

Recumbent deoxygenation in mild/moderate liver cirrhosis: the "clinodeoxia". The ortho-clino paradigm

BACKGROUND

While the effects of postural change on arterial oxygenation have been well documented in normal subjects, and attributed to the relationship of closing volume (CV) to the tidal volume, in liver cirrhosis such postural changes have been evaluated mainly in a rare, peculiar clinical end-stage condition which is characterized by increased dyspnea shifting from supine to upright position ("platypnea"). The latter is associated with worsening of PaO2 ("orthodeoxia"). We evaluated the effects of postural changes on arterial oxygenation in patients affected by mild/moderate liver cirrhosis.

METHODS

We performed pulmonary function tests and arterial blood gas evaluation in sitting and supine positions in 22 patients with mild/moderate liver cirrhosis, biopsy-proved, and 22 matched non-smokers control subjects.

RESULTS

Recumbency elicited a decrease of PaO2 (Δ(sup-sit)PaO2) in 19 out of 22 controls and in all but one cirrhotics. The magnitude of this postural change was significantly (p = 0.04) greater in cirrhotics (9.6 ± 5.3%) compared to controls (6.7 ± 3.7%). In the subset of cirrhotics younger than 60 yrs and with PaO2 greater than 80 mmHg in sitting position, the Δ(sup-sit)PaO2 in recumbency further increased to 12 ± 5.8%, significantly (p = 0.014) greater than in same subgroup of controls (7.1 ± 3.8%).

CONCLUSIONS

In mild/moderate liver cirrhosis the postural variations in PaO2 follow the normal trends, but are of greater magnitude probably as a consequence of hypoventilated units of lung for postural and disease-linked tidal airway closure, resulting in more pronounced recumbent hypoxemia ("clinodeoxia").

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.

Limitations and strengths of doppler/echo pulmonary artery systolic pressure-right heart catheterization correlations: a systematic literature review

AIMS

Because many recent studies have questioned the accuracy of Doppler echocardiography (D) in determining pulmonary artery systolic pressure (PASP), we performed a detailed literature analysis attempting add clarity.

METHODS AND RESULTS

Studies through 2011 comparing D and right heart catheterization (RHC) PASP, with at least 25 studied patients and reporting correlation coefficients (r) were identified. Patient demographics, study characteristics, the percent of patients studied for left or right heart pathologies, and study biases were determined. After adjusting for differing study sizes, each study's r value was used as a single datapoint and dichotomized above or below the entire cohort's mean values. From 32 studies 2604 D-RHC parings were reported. Their overall weighted r was 0.68 ± 0.19. Poorer correlations were found for right heart pathologies compared to left heart pathologies (r = 0.58 vs. 0.84, P < 0.001) and for normal PASP patients in a study compared to abnormal PASP patients (r = 0.55 vs. 0.82, P < 0.001). Studies with predominately right heart pathology had a significantly greater D-RHC time difference, fewer successful D determinations, a greater percentage of normal PASPs on RHC, and more between-method differences >10 mmHg. Metaregression analyses indicated that both right heart pathology predominance and a greater percent of normal PASPs on RHC remained associated with poorer correlations.

CONCLUSIONS

D PASP-RHC correlations were high and between-method differences less in patients with left heart pathology but were poorer for right heart diseases and studies with proportionately more normal PASPs on RHC for which further study is needed.

Role of pretransplant echocardiographic evaluation in predicting outcomes following liver transplantation

Maintenance of cardiac function is critical to the survival of patients with end-stage liver disease after liver transplantation (LT). We sought to determine whether pre-LT echocardiographic indices of right heart structure and function were independently predictive of morbidity and mortality post-LT. We retrospectively studied 216 consecutive patients who underwent pre-LT 2-dimensional/Doppler echocardiography with subsequent LT from 2007 to 2010. A blinded reader analyzed multiple echocardiographic parameters, including right ventricular structure and function, pulmonary artery systolic pressure (PASP) and the presence and severity of tricuspid regurgitation (TR). On univariate analysis, Model of End-Stage Liver Disease (MELD) score, PASP, presence of ≥mild TR, post-operative renal replacement therapy (RRT) and spontaneous bacterial peritonitis were found to be significant predictors of adverse outcomes. On multivariate analysis, only ≥mild TR was found to predict both patient mortality (p = 0.0024, HR = 3.91, 95% CI: 1.62-9.44) and graft failure (p = 0.0010, HR = 3.70, 95% CI: 1.70-8.06). PASP and MELD correlated with post-LT intensive care unit length of stay (LOS) and, along with hemodialysis, were associated with hospital LOS and time on ventilator. In conclusion, pre-LT echocardiographic assessments of the right heart may be useful in predicting post-LT morbidity and mortality and guiding the selection of appropriate LT candidates.

Hepatopulmonary syndrome and portopulmonary hypertension

Hepatopulmonary syndrome and portopulmonary hypertension are 2 of many diseases that affect the lungs in patients with liver disease. The 2 vascular conditions are often confused. We review both hepatopulmonary syndrome and portopulmonary hypertension to better understand their pathophysiologies, clinical presentations, tools to aid in differentiating and diagnosing the disease states, treatment options, and influences on patient prognosis. We also consider patient viability for liver transplantation.

Safety of transradial cardiac catheterization in patients with end-stage liver disease

BACKGROUND

Transradial access may be advantageous for patients with end-stage liver disease (ESLD) who need to undergo left heart catheterization (LHC). We aimed to assess the safety of transradial cardiac catheterization in patients listed for orthotopic liver transplantation.

METHODS

This is a retrospective analysis of consecutive adult patients with the diagnosis of ESLD, who underwent LHC via transradial access as part of a pre-operative liver transplantation evaluation. All the patients also underwent right heart catheterization (RHC) via brachial or femoral vein. The primary outcome measure was procedure-related major bleeding. Secondary outcomes included access site minor bleeding, in-hospital mortality, radial access failure, and acute kidney injury.

RESULTS

A total of 82 consecutive patients with ESLD, who underwent LHC via transradial access, were enrolled in the study. All patients also underwent RHC (n = 45 via brachial and n = 37 via femoral vein). The median age was 59 (54, 67) years old, and 58% were male. History of coronary artery disease or heart failure was present in 17% of patients. The median MELD score was 19 (13, 24.5), baseline hemoglobin was 10.5 mg/dL (9.4, 11.8), INR was 1.4 (1.2, 1.8) and platelets were 74,000 (53,000, 117,000)/mm(3) . The most common etiology of liver failure was viral hepatitis (51%), followed by alcoholic cirrhosis (24%) and non-alcoholic steatohepatitis (21%). Angiographically significant coronary artery disease was present in 17 (21%) patients. Major bleeding and acute kidney injury each occurred in two patients (2.4%). There were no instances of vascular complications. There were no deaths attributable to complications from cardiac catheterization.

CONCLUSION

Upper extremity right and left heart catheterization appears to be a safe method to evaluate coronary anatomy and hemodynamics in a severely ill population of patients with ESLD awaiting transplant.

Echocardiography in liver transplant candidates

Involvement of the cardiovascular system in patients with end-stage liver disease (ESLD) is well recognized and may be seen in several scenarios in adult liver transplantation (LT) candidates. The hemodynamic effects of ESLD may result in apparent heart disease, or in some instances may mask cardiac disease. Alternatively, cardiac disease can occasionally be the underlying etiology of ESLD. LT imposes significant hemodynamic stresses, with cardiovascular complications accounting for considerable perioperative mortality and morbidity. Pre-operative assessment of the cardiac status of LT candidates is thus critically important for risk stratification and management. Cardiac imaging plays an integral role in the assessment of LT candidates. In this review, we discuss the role of cardiac imaging, including transthoracic echocardiography with Doppler and contrast enhancement, noninvasive functional assessment for routine pre-operative assessment of coronary artery disease, and transesophageal echocardiography in select cases to aid in intra-operative fluid management and monitoring in LT candidates.

Echocardiography for the detection of portopulmonary hypertension in liver transplant candidates: an analysis of cutoff values

Portopulmonary hypertension (POPH), a complication of chronic liver disease, may be a contraindication to liver transplantation (LT) because of the elevated risk of peritransplant and posttransplant morbidity and mortality. Because POPH is frequently asymptomatic, screening with echocardiography is recommended. The only reliable technique, however, for diagnosing POPH is right heart catheterization (RHC). The aims of this study were to evaluate the current estimated systolic pulmonary artery pressure (sPAP) cutoff value of 30 mm Hg and to determine a better cutoff value. One hundred fifty-two patients underwent pretransplant echocardiography between January 2005 and December 2010. These echocardiographic results were compared with pulmonary artery pressures measured during the pretransplant workup or at the beginning of the transplantation procedure (both by catheterization). With a cutoff value of 30 mm Hg, 74 of the 152 patients met the criteria for POPH on echocardiography, although the diagnosis was confirmed in only 7 patients during catheterization; this resulted in a specificity of 54%. It would have been more accurate to use a cutoff value of 38 mm Hg, which had a maximal specificity of 82% and, at the same time, guaranteed a sensitivity and negative predictive value of 100%. With the incorporation of the presence or absence of right ventricular dilatation, the specificity even increased to 93% for this new cutoff value. In conclusion, the prevalence of POPH was 4.6% among LT candidates in this study. We can recommend that LT candidates with an sPAP > 38 mm Hg should be referred for RHC. With the cutoff value increased from 30 to 38 mm Hg, the number of patients undergoing invasive RHC during their evaluation could be safely reduced.