Structural and pathologic changes in the lung vasculature in chronic liver disease

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.

Acute heart failure after liver transplantation: A narrative review

Acute heart failure (AHF) is an under recognized yet potentially lethal complication after liver transplantation (LT) surgery. The increase in incidence of liver transplantation amongst high-risk patients and the leniency in the criteria for transplantation, predisposes these patients to postoperative AHF and the antecedent morbidity and mortality. The inability of conventional preoperative cardiovascular testing to accurately identify patients at risk for post-LT AHF poses a considerable challenge to clinicians caring for these patients. Even if high-risk patients are identified, there is considerable ambiguity in the candidacy for transplantation as well as optimization strategies that could potentially prevent the development of AHF in the postoperative period. The intraoperative and postoperative management of patients who develop AHF is also challenging and requires a well-coordinated multidisciplinary approach. The use of mechanical circulatory support in patients with refractory heart failure has the potential to improve outcomes but its use in this complex patient population can be associated with significant complications and requires a stringent risk-benefit analysis on a case-by-case basis.

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.

Hypoxia due to intrapulmonary vascular dilatation in a toddler with a congenital portacaval shunt: case report

Background

The term hepatopulmonary syndrome typically applies to cyanosis that results from “intrapulmonary vascular dilatation” due to advanced liver disease. Similar findings may result from a congenital portosystemic shunt without liver disease. An adverse consequence of such shunts is intrapulmonary vascular dilatation, which affects the microvascular gas exchange units for oxygen.

Case presentation

Here, we describe a toddler with chronic cyanosis, exercise intolerance, and finger clubbing due to a malformation shunt between the portal vein and the inferior vena cava. A transcatheter embolization of the shunt resulted in resolution of his findings.

Conclusions

Congenital portosystemic shunts need to be considered in the differential diagnosis of cyanosis.

Electronic supplementary material

The online version of this article (10.1186/s12890-019-0788-8) contains supplementary material, which is available to authorized users.

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.

Hepatopulmonary syndrome has low prevalence of pulmonary vascular abnormalities on chest computed tomography

Purpose

Hepatopulmonary syndrome (HPS) is defined as an arterial oxygenation defect induced by intrapulmonary vascular dilatations associated with hepatic disease. This study aimed to assess the prevalence of type 1 and 2 pulmonary vascular abnormalities on chest computed tomography (CT) in patients with cirrhosis and HPS and to characterize intra- and interobserver reliability.

Materials and methods

Two thoracic radiologists retrospectively evaluated chest CT scans from 38 cirrhosis patients with HPS. They classified the pulmonary vascular abnormalities as type 1 (multiple dilated distal pulmonary arteries), type 2(nodular dilatation or individual pulmonary arterial malformation), or absence of abnormality. Furthermore, they measured the diameters of the central pulmonary arteries and subsegmental pulmonary arteries and bronchi. We analyzed the prevalence, intraobserver reliability, and interobserver reliability of abnormal CT findings related to HPS, and the correlation of these findings with partial arterial oxygen pressure (PaO₂).

Results

The overall prevalence of pulmonary vascular abnormalities was 28.9% (95% confidence intervals: 15.4%, 45.9%). Moreover, 26.3% of patients had type 1 abnormality (13.4%, 43.1%) and 2.6% of patients had type 2 abnormality (0.0%, 13.8%). The intraobserver reliability kappa value was 0.666 (0.40, 0.91) and the interobserver kappa value was 0.443 (0.12, 0.77). There was no correlation between pulmonary vascular abnormalities on CT and PaO₂ values.

Conclusions

The prevalence of pulmonary vascular abnormalities on chest CT of patients with cirrhosis and HPS is low and not correlated with PaO₂. These findings question the usefulness of chest CT for the evaluation of patients with cirrhosis and HPS.

Vascular syndromes in liver cirrhosis

Liver cirrhosis is associated with multiple vascular syndromes affecting almost all body systems. Many of these syndromes are directly related to impaired liver function and sometimes reversible after liver transplantation while others arise secondary to portal hypertension and ascites. Altered expression of angiogenic and vasoactive compounds (most importantly nitric oxide), endothelial dysfunction, dysregulated neurohormonal control, and systemic inflammatory state play differential roles in mediating homeostatic instability and abnormal vasogenic response. Important vascular features encountered in liver disease include portal hypertension, splanchnic overflow, abnormal angiogenesis and shunts, portopulmonary syndrome, hepatopulmonary syndrome, and systemic hyperdynamic circulation. Redistribution of effective circulatory volume deviating from vital organs and pooling in splanchnic circulation is also encountered in liver patients which may lead to devastating outcomes as hepatorenal syndrome. Etiologically, vascular syndromes are not isolated phenomena and vascular dysfunction in one system may lead to the development of another in a different system. This review focuses on understanding the pathophysiological factors underlying vascular syndromes related to chronic liver disease and the potential links among them. Many of these syndromes are associated with high mortality, thus it is crucial to look for early biomarkers for these syndromes and develop novel preventive and therapeutic strategies.

Pulmonary transit time derived from pulmonary angiography for the diagnosis of hepatopulmonary syndrome

BACKGROUND & AIMS

Pulmonary transit time (PTT) is the transit time of blood from the right side of the heart to the left side of the heart. The aim of the present study was to evaluate the role of the PTT derived from pulmonary angiography in the diagnosis of hepatopulmonary syndrome (HPS).

METHODS

From December 2014 to September 2015, all patients with chronic liver disease and/or portal hypertension undergoing a venous interventional radiologic procedure at our institution were eligible for inclusion in this prospective study. Pulmonary angiography was performed in all patients, and the PTT, which was defined as the time between opacification of the pulmonary trunk and the right border of the left atrium, was determined.

RESULTS

A total of 53 patients were included, 20 of whom had a positive contrast-enhanced echocardiography result and an elevated alveolar-arterial oxygen gradient were considered to have HPS. PTT was significantly shorter in patients with HPS than in those without [median, 3.34 (interquartile range, 3.01-3.67) seconds vs 4.0 (interquartile range, 3.67-4.17) seconds; P < .001]. The area under the receiver operating characteristic curve of PTT for diagnosing HPS was 0.83 (95% confidence interval, 0.70-0.92). The optimal cut-off value of PTT for diagnosing HPS, based on Youden's index, was 3.55 seconds. The sensitivity, specificity and accuracy of PTT < 3.55 seconds for diagnosing HPS were 70%, 85% and 79% respectively.

CONCLUSIONS

Pulmonary transit time derived from pulmonary angiography is useful for diagnosing HPS, especially for patients with intracardiac shunts and inadequate echocardiographic windows.

Review article: Update on current and emergent data on hepatopulmonary syndrome

Hepatopulmonary syndrome (HPS) is a frequent pulmonary complication of end-stage liver disease, characterized by impaired arterial oxygenation induced by intrapulmonary vascular dilatation. Its prevalence ranges from 4% to 47% in patients with cirrhosis due to the different diagnostic criteria applied among different studies. Nitric oxide overproduction and angiogenesis seem to be the hallmarks of a complicated pathogenetic mechanism, leading to intrapulmonary shunting and ventilation-perfusion mismatch. A classification of HPS according to the severity of hypoxemia has been suggested. Contrast-enhanced echocardiography represents the gold standard method for the detection of intrapulmonary vascular dilatations which is required, in combination with an elevated alveolar arterial gradient to set the diagnosis. The only effective treatment which can modify the syndrome’s natural history is liver transplantation. Although it is usually asymptomatic, HPS imparts a high risk of pretransplantation mortality, independently of the severity of liver disease, while there is variable data concerning survival rates after liver transplantation. The potential of myocardial involvement in the setting of HPS has also gained increasing interest in recent research. The aim of this review is to critically approach the existing literature of HPS and emphasize unclear points that remain to be unraveled by future research.

Assessing the kinetics of microbubble appearance in cirrhotic patients using transthoracic saline contrast-enhanced echocardiography

BACKGROUND

The number of cardiac cycles that need to be reviewed by echocardiography before a significant intrapulmonary shunt can be excluded remains unclear.

METHODS

We retrospectively identified patients with cirrhosis who underwent technetium-99 m-labeled macroaggregated albumin scanning. The kinetics of bubble appearance after the injection of agitated saline during transthoracic echocardiograms were assessed in these patients.

RESULTS

For the 64 eligible patients, the mean ± SD age was 56 ± 9 years. The median (IQR) shunt fraction by radionuclide scanning was 7.7% (2.8%-19.9%). Microbubbles were seen in the left atrium (LA) and left ventricle (LV) at a median (IQR) of 4 (2-5) and 4 (2-5) beats, respectively. The number of heart cycles before microbubbles appeared in the LA or LV was inversely associated with the nuclear scanning shunt fraction (R = -0.42, P = .001, R = -0.46, P < .001, respectively). If no microbubbles were detected by heart cycle 7, the shunt fraction was uniformly less than 3%. Patients with arterial oxygen <60 mm Hg, compared to ≥60 mm Hg, had earlier appearance of microbubbles in the left heart chambers (2.6 ± 1.9 vs 4.0 ± 2.3 beats, P = .046).

CONCLUSIONS

In patients with advanced cirrhosis suspected of having hepatopulmonary syndrome, a greater shunt fraction during nuclear scanning was associated with more pronounced hypoxemia and a prompt and more intense appearance of microbubbles in the left-sided heart chambers. Patients with a shunt fraction above 3% have microbubbles in the LA or LV at some point during the first seven heart cycles.

Patent foramen ovale in liver transplant recipients does not negatively impact short-term outcomes

AIM

Patent foramen ovale (PFO) is a common atrial septal defect that is largely asymptomatic and often undiagnosed. The impact of a PFO in patients undergoing liver transplantation (LT) is unknown.

OBJECTIVE

Assess the impact of PFO and physiologic intrapulmonary shunt (IPS) on the perioperative outcomes of patients who underwent LT.

METHODS

We performed a retrospective, intention-to-treat analysis of patients with PFO and controls without PFO who underwent LT at Mayo Clinic in Florida between 2008 and 2013. Patients with physiologic IPS were also analyzed. The cohorts were compared for baseline characteristics, length of stay in the intensive care unit (ICU), postoperative oxygen requirements, 30-d cerebrovascular accidents, and mortality.

RESULTS

Of the 935 patients who underwent LT, 10.4% had proven PFO by pre-LT echocardiogram. Control patients (n = 101) were statistically older than PFO and IPS (n = 56) patients, but similar in sex, BMI, Model for End-stage Liver Disease score, American Society of Anesthesiologist score, and left ventricular ejection fraction. PFO and IPS patients had similar length of stay in the ICU, mechanical ventilation times, post-LT oxygen requirements, and 30-d mortality compared to controls. Subgroup analysis showed similar outcomes for large PFO and IPS patients to controls.

CONCLUSIONS

The presence of PFO did not have a negative impact on perioperative LT outcomes.

The Art and Science of Diagnosing and Treating Lung and Heart Disease Secondary to Liver Disease

Patients with chronic liver disease are at risk of extrahepatic complications related to cirrhosis and portal hypertension, as well as organ-specific complications of certain liver diseases. These complications can compromise quality of life, while also increasing morbidity and mortality before and after liver transplantation. Patients with chronic liver disease are at risk for pulmonary complications of hepatopulmonary syndrome and portopulmonary syndrome; the cardiac complication fall under the general concept of cirrhotic cardiomyopathy, which can affect systolic and diastolic function, as well as cardiac conduction. In addition, patients with certain diseases are at risk of lung and/or cardiac complications that are specific to the primary disease (ie, emphysema in α-1-antitrypsin deficiency) or occur with increased incidence in certain conditions (ie, ischemic heart disease associated with nonalcoholic steatohepatitis). This article focuses on the epidemiology, clinical presentation, pathogenesis, treatment options, and role of transplantation for lung and heart diseases secondary to liver disease, while also highlighting select liver diseases that directly affect the lungs and heart.

Developmental lung malformations in children: recent advances in imaging techniques, classification system, and imaging findings

Congenital lung anomalies represent a diverse group of developmental malformations of the lung parenchyma, arterial supply, and venous drainage, which may present anywhere from the prenatal period through adulthood. It is imperative for radiologists to be aware of imaging techniques and imaging appearance of these anomalies across the pediatric age range. This review presents the spectrum of these lesions that are often encountered in daily clinical practice. Each anomaly is discussed in terms of underlying etiology, clinical presentation, and imaging characterization with emphasis on the most up-to-date research and treatment. Knowledge of these areas is essential for accurate, timely diagnosis, which aids in optimizing patient outcomes.

Hepatopulmonary Syndrome

Hepatopulmonary syndrome (HPS) is a pulmonary complication observed in patients with chronic liver disease and/or portal hypertension, attributable to an intrapulmonary vascular dilatation that may induce severe hypoxemia. Microvascular dilation and angiogenesis in the lung have been identified as pathologic features that drive gas exchange abnormalities in experimental HPS. Pulse oximetry is a useful screening test for HPS, which can guide subsequent use of arterial blood gases. Contrast-enhanced echocardiography, perfusion lung scanning, and pulmonary arteriography are three currently used diagnostic imaging modalities that identify the presence of intrapulmonary vascular abnormalities. The presence of HPS increases mortality and impairs quality of life, but is reversible with liver transplantation. No medical therapy is established as effective for HPS. At the present time, liver transplantation is the only available treatment for HPS.

"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.

A comparison of two common bile duct ligation methods to establish hepatopulmonary syndrome animal models

The major drawback of the current common bile duct ligation (CBDL)-induced hepatopulmonary syndrome (HPS) animal model is the extremely high mortality rate that hinders experimental studies. The purpose of this study was to investigate an improved method of CBDL with the goal of developing a simple and reproducible rat HPS model after a single CBDL treatment. Two groups of male Sprague–Dawley rats underwent separate methods of CBDL: (1) the upper common bile duct ligation (UCBDL) group ( n = 40), in which the first ligature was made near the junction of the hepatic ducts, and the second ligature was made above the entrance of the pancreatic duct; (2) the middle of the common bile duct ligation (MCBDL) group ( n = 40), in which the first ligature was made in the middle of the common bile duct, and the second ligature was made above the entrance of the pancreatic duct. The CBDL-induced HPS rats were evaluated by pulse oximeter, arterial blood analysis, histopathology, and cerebral uptake of intravenous technetium-99m-labeled albumin macroaggregates (which reflects intrapulmonary vascular dilation). The mortality rates of the UCBDL group and the MCBDL group were 42.5% and 77.5%, respectively ( P < 0.05). These results suggest that the UCBDL, a single improved procedure, provides a better method compared to the established HPS model, because of the relatively high success rate and the decreased risk of complications.

Clinical aspects of portopulmonary hypertension

Portopulmonary hypertension (PoPH) is an often neglected form of pulmonary hypertension where pulmonary hypertension occurs in the presence of portal hypertension. PoPH is important to diagnose and treat as it may improve the patient's quality of life and improve the outcome after liver transplantation. In this review, we discuss the clinical aspects of PoPH including its pathophysiology, diagnosis, treatment, and prognosis.

Are the spider angiomas skin markers of hepatopulmonary syndrome?

CONTEXT

Hepatopathies can significantly influence both veins and arteries, these changes may cause some cutaneous stigmas, such as spider angioma (SA) and some systemic vascular changes, such as those observed in hepatopulmonary syndrome (HPS). Based on this common pathophysiological root we can assume that the SA can be skin markers of HPS.

OBJECTIVE

The objective of this study is to assess whether there is a relationship between the presence of SA and HPS.

METHODS

Records of 40 patients with liver cirrhosis who underwent contrast echocardiography were evaluated, in which we researched the description of SA, physical examination, and other clinical and laboratory data. For diagnosis of HPS we use these signs of the disease: presence of liver disease (cirrhosis in the case), abnormalities in gas exchange by arterial blood gases, and evidence of pulmonary vasodilations by the contrast echocardiography.

RESULTS

The SA were found in 21/40 (52.5%) patients and hepatopulmonary syndrome in 9/40 (22.5%). The HPS was observed in 8/21 (38.1%) of patients with SA and 1/19 (5.3%) patients were without this sign (P<0.01). We found no statistically significant difference between the SA and the presence of HPS with sex or age. Patients with SA had a higher hypoxemia [PaO2 84.8 ± 11.5 mmHg and 19.8 ± 14.7 mmHg alveolar-arterial gradient of oxygen (AAG)] than those without SA (PaO2 90.8 ± 10.7 mmHg and 10.9 ± 11.7 AAG mmHg) (P<0.05).

CONCLUSION

Our findings show a correlation between the presence of SA and HPS, suggesting that the SA may be cutaneous markers of HPS.

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.

Normal and abnormal pulmonary arteriovenous shunting: occurrence and mechanisms

Severe cyanosis due to pulmonary arteriovenous fistulas occurs often after a bidirectional superior cavopulmonary anastomosis (Glenn operation) and also in some congenital anomalies in which hepatic venous blood bypasses the lungs in the first passage. Relocation of hepatic flow into the lungs usually causes these fistulas to disappear. Similar pulmonary arteriovenous fistulas are observed in hereditary haemorrhagic telangiectasia, and in liver disease (hepatopulmonary syndrome). There is no convincing identification yet of a responsible hepatic factor that produces these lesions. Candidates for such a factor are reviewed, and the possibility of angiotensin or bradykinin contributing to the fistulas is discussed.

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.

Hepatopulmonary syndrome: update on pathogenesis and clinical features

Hepatopulmonary syndrome (HPS) is a serious vascular complication of liver disease that occurs in 5-32% of patients with cirrhosis. The presence of HPS markedly increases mortality. No effective medical therapies are currently available and liver transplantation is the only established treatment option for HPS. The definition and diagnosis of HPS are established by the presence of a triad of liver disease with intrapulmonary vascular dilation that causes abnormal arterial gas exchange. Experimental biliary cirrhosis induced by common bile duct ligation in the rat reproduces the pulmonary vascular and gas exchange abnormalities of human HPS and serves as a pertinent animal model. Pulmonary microvascular dilation and angiogenesis are two central pathogenic features that drive abnormal pulmonary gas exchange in experimental HPS, and thus might underlie HPS in humans. Defining the mechanisms involved in the microvascular alterations of HPS has the potential to lead to effective medical therapies. This Review focuses on the current understanding of the pathogenesis, clinical features and management of HPS.

Effects of caffeic acid phenethyl ester (CAPE) on hepatopulmonary syndrome

The aim of this study was to investigate the effects of caffeic acid phenethyl ester (CAPE) on inflammatory and related histopathological changes in the lung and liver in experimental hepatopulmonary syndrome (HPS) model. Forty Sprague Dawley rats were used in this study. The animals were divided into four groups of ten rats each. Group 1 and 2 was subjected the common bile duct (CBD) but not ligated, Group 3; (cirrhosis + saline): the CBD was ligated and was given intraperitoneal saline infusion treatment during 5 weeks. Group 4; (cirrhosis + CAPE): the CBD was ligated and was given intraperitoneal CAPE infusion treatment during 5 weeks. A 5-week waiting period was observed for the development of cirrhosis and the rats' lungs and liver were taken for histopathological examination. The induction of HPS resulted in a significant increase in serum bilurubin, AST, ALT, and NO levels, and decrease PO2 and O2 saturation. The use of CAPE significant decrease these parameters. Histopathological examination revealed less congestion, portal inflammation, and nodular formations of the liver, and less congestion, emphysematous and inflammatory changes and smallest perialviolar vascular diameters, in the lung in the cirrhosis + CAPE groups than in the other groups. CAPE treatment may be a potential approach for the treatment of hepatopulmonary syndrome in the future.

Portopulmonary hypertension: challenges in diagnosis and management

Portopulmonary hypertension is defined as the combination of pulmonary arterial hypertension with portal hypertension and presents management complications in patients awaiting liver transplantation. The combination of these vascular disorders has a marked impact on mortality. At present the recommendations for management are limited because of the paucity of definitive clinical trials. We have reviewed the available data on prevalence, diagnosis and treatment. It is clearly time to more formally approach the study of this patient population.

Pulmonary complications of cirrhosis

Pulmonary vascular complications of liver disease comprise two distinct clinical entities: hepatopulmonary syndrome (HPS-microvascular dilatation and angiogenesis) and portopulmonary hypertension (POPH-vasoconstriction and remodeling in resistance vessels). These complications occur in similar pathophysiologic environments and may share pathogenic mechanisms. HPS is found in 15% to 30% of patients with cirrhosis and its presence increases mortality and the risks of liver transplantation, particularly when hypoxemia is present. Contrast echocardiography and arterial blood gas analysis are required to establish the diagnosis. No medical therapies are available, although liver transplantation is effective in reversing the syndrome. POPH is found in 4% to 8% of patients undergoing liver transplantation evaluation, and the presence of moderate to severe disease significantly increases perioperative transplant mortality. Transthoracic echocardiography is recommended for screening and right-heart catheterization is required to establish the diagnosis. Medical therapies are increasingly effective in improving pulmonary vascular hemodynamics in POPH and may result in better perioperative outcomes.

Effect of heme oxygenase-1 on renal function in rats with liver cirrhosis

AIM: To investigate the role of heme oxygenase-1 (HO-1) in pathogenesis of experimental hepatorenal syndrome (HRS).

METHODS: Rats were divided into liver cirrhotic group, zinc protoporphyrin IX (ZnPP) treatment group, cobalt protoporphyrin (CoPP) treatment group and sham group. Biliary cirrhosis was established by bile duct ligation in the first three groups. Rats in the ZnPP and CoPP treatment groups received intraperitoneal injection of ZnPP and CoPP, respectively, 24 h before sample collection. Expression of HO-1 mRNA in kidney was detected by reverse-transcription polymerase chain reaction, while protein expression was determined by immunohistochemical analysis. Hematoxylin and eosin staining was performed to observe liver cirrhosis and renal structure. Renal artery blood flow, mean arterial pressure and portal vein pressure, 24 h total urinary volume, serum and urine sodium concentrations, and creatinine clearance rate (Ccr) were also measured.

RESULTS: The HO-1 mRNA and protein expression levels in kidney, 24 h total urinary volume, renal artery blood flow, serum and urine sodium concentration and Ccr were lower in cirrhotic group than in sham group (P < 0.05). However, they were significantly lower in ZnPP treatment group than in cirrhotic group and significantly higher in CoPP treatment group than in cirrhotic group (P < 0.05).

CONCLUSION: Low HO-1 expression level in kidney is an important factor for experimental HRS.

Respiratory failure and hypoxemia in the cirrhotic patient including hepatopulmonary syndrome

PURPOSE OF REVIEW

Liver cirrhosis and portal hypertension present with three unique pulmonary complications that are the subject of ongoing clinical research: hepatopulmonary syndrome, portopulmonary hypertension (POPH), and hepatic hydrothorax. The present article is based on a review of the current literature on how to manage these disorders, which are highly important to both anesthesiologists and intensive care physicians.

RECENT FINDINGS

Hepatopulmonary syndrome leads to progressive hypoxemia through diffuse vasodilatation of the pulmonary microcirculation. Liver transplantation, although associated with increased mortality, is the only viable treatment. POPH occurs when vascular remodeling triggers an increase in pulmonary artery pressure and resistance. The role of liver transplantation in POPH is controversial given the excessive mortality in patients with moderate to severe POPH. Medical treatment is able to decrease pulmonary artery pressures, though multicenter randomized controlled trials showing improved outcome are lacking to date. Ultrasound plays an increasingly important role in the diagnosis of all three conditions.

SUMMARY

Patients with end-stage liver disease are at risk for respiratory failure and hypoxemia and need to be screened for hepatopulmonary syndrome, POPH, and hepatic hydrothorax. Failure to timely recognize and adequately treat these complications of cirrhosis may have severe consequences.

Bedside sublingual video imaging of microcirculation in assessing bacterial infection in cirrhosis

Bacterial infections are common in cirrhosis and can lead to life-threatening complications. Sidestream dark-field (SDF) imaging has recently emerged as a noninvasive tool for capturing real-time video images of sublingual microcirculation in critically ill patients with sepsis. The objective of this study was to assess the utility of SDF in determining underlying infection in patients with cirrhosis. Sublingual microcirculation was compared among patients with compensated cirrhosis (Group A, n=13), cirrhosis without sepsis (Group B, n=18), cirrhosis with sepsis (Group C, n=14), and sepsis only (Group D, n=10). The blood flow was semi-quantitatively evaluated in four equal quadrants in small (10-25 mm); medium (26-50 mm); and large (51-100 mm) sublingual capillaries. The blood flow was described as no flow (0), intermittent flow (1), sluggish flow (2), and continuous flow (3). The overall flow score or microvascular flow index (MFI) was measured for quantitative assessment of microcirculation and predicting power for concurrent infection in cirrhosis. Marked impairment was observed at all levels of microvasculature in Groups B and C when compared with Group A. This effect was restricted to small vessels only when Group B was compared with Group C. MFI<1.5 was found to have highest sensitivity (100%) and specificity (100%) for infection in decompensated cirrhosis. SDF imaging of sublingual microcirculation can be a useful bedside diagnostic tool to assess bacterial infection in cirrhosis.

Multidetector CT evaluation of congenital lung anomalies

Congenital lung anomalies vary widely in their clinical manifestation and imaging appearance. Although radiographs play a role in the incidental detection and initial imaging evaluation in patients with clinical suspicion of congenital lung anomalies, cross-sectional imaging such as computer tomography (CT) is frequently required for confirmation of diagnosis, further characterization, and preoperative evaluation in the case of surgical lesions. Recently, with the development and widespread availability of multidetector CT scanners, CT has assumed a greater role in the noninvasive evaluation of congenital lung anomalies. The combination of fast speed, high spatial resolution, and enhanced quality of multiplanar reformation and three-dimensional reconstructions makes multidetector CT an ideal noninvasive method for evaluating congenital lung anomalies. In this article, the authors review the multidetector CT technique for evaluation of congenital lung anomalies. Important clinical aspects, characteristic imaging features, and key points that allow differentiation among various anomalies are highlighted for a variety of common and uncommon conditions.

Inhaled iloprost for hepatopulmonary syndrome: improvement of hypoxemia

Hepatopulmonary syndrome is characterized by advanced liver disease, hypoxemia, and intrapulmonary shunting. The only reported curative option is orthotopic liver transplantation. We describe here a beneficial effect of inhaled prostacyclin including a decrease in respiratory symptoms and improved oxygenation in this clinical situation, with no approved pharmacological long-term therapy. The prostanoid iloprost, approved for pulmonary and portopulmonary hypertension, caused an increase in oxygenation, relief of dyspnea, and increased exercise tolerance in a patient suffering from liver-cirrhosis-associated hepatopulmonary syndrome. After liver transplantation, restitution of hepatopulmonary syndrome did not occur immediately. Inhaling iloprost resulted in improved physical condition and better clinical rehabilitation potential until hypoxemia finally resolved 3 months after transplantation. Therefore, iloprost could improve quality of life in patients with hepatopulmonary syndrome waiting for liver transplantation and post surgery until the resolution of the hypoxemia.

Hepatopulmonary syndrome, an unusual cause of hypoxemia

A six-year-old boy presented with cough, cyanosis and clubbing. Investigations revealed hypoxia (PaO2 53 mm Hg on room air) which was only partially correctable (PaO2 73 mm Hg) with 100% oxygen administered through a non re breathing face mask. Liver function tests showed elevated total bilirubin, and transaminases, liver biopsy confirmed chronic hepatitis and endoscopy showed grade three varices. A contrast enhanced echocardiography (bubble study) revealed pulmonary arterio-venous communication. A diagnosis of hepatopulmonary syndrome was made based on the triad of hypoxemia, liver disease and intra pulmonary vascular communications.

Portopulmonary hypertension

Portopulmonary hypertension is a common condition in patients who have portal hypertension. This article reviews the definition and clinical presentation of this disorder and outlines our current understanding of its pathophysiology. A diagnostic approach is provided , and novel medical therapies that are being investigated to treat this condition are discussed. Finally, the safety of liver transplantation in patients who have portopulmonary hypertension is reviewed.

Hepatopulmonary syndrome

The hepatopulmonary syndrome (HPS) is an important and often under-recognized vascular complication of cirrhosis and portal hypertension characterized by pulmonary vascular dilatation, which results in hypoxemia. This syndrome is identified in as many as 20% of patients who are evaluated for orthotopic liver transplantation (OLT), and it has recently been found to increase mortality in affected patients, particularly when hypoxemia is severe. Currently, OLT is the only therapy established to reverse intrapulmonary vasodilatation, although postoperative mortality is increased in patients with severe hypoxemia. No randomized controlled trials of pharmacologic therapies have been undertaken, but supplemental oxygen improves oxygenation. Data derived from case reports, small studies, and experimental models suggest that pharmacologic therapies may be effective. In cirrhotic patients with HPS, particularly those with moderate hypoxemia (PaO2 < 60 mmHg), OLT should be considered prior to the development of severe deoxygenation. Supplemental oxygen should be given to patients with a PaO2 < 60 mmHg or those with exercise oxygen desaturation. For those patients with mild hypoxemia or those who are not OLT candidates, a trial of pharmacologic treatment may be considered.

The diagnosis and treatment of hepatopulmonary syndrome

Few prognostic indicators and outcomes reported for patients who have hepatopulmonary syndrome can be consistently reproduced between institutions. The lack of practice recommendations based upon consistent and predictable outcomes creates uncertainty for physicians trying to make the best patient choices. With the scarcity of donor organs, these issues are of particular importance when transplantation in considered as a treatment option. Much uncertainty arises from the basic tasks of making an accurate diagnosis in patients who have symptoms suggestive of hepatopulmonary syndrome. This article focuses on problems that underlie diagnostic accuracy and uses this information to appraise critically outcomes literature.

Reversion of severe hepatopulmonary syndrome in a non cirrhotic patient after corticosteroid treatment for granulomatous hepatitis: A case report and review of the literature

Hepatopulmonary syndrome (HPS) is defined as a clinical triad including liver disease, abnormal pulmonary gas exchange and evidence of intrapulmonary vascular dilatations. We report a 61-year-old male presented with fatigue, long-lasting fever, loss of weight, signs of portal hypertension, hepatosplenomegaly, cholestasis and progressive dyspnoea over the last year. Clinical, laboratory and histological findings confirmed the diagnosis of granulomatous hepatitis. HPS due to hepatic granuloma-induced portal hypertension was proved to be the cause of severe hypoxemia of the patient as confirmed by contrast-enhanced echocardiography. Reversion of HPS after corticosteroid therapy was confirmed by a new contrast-enhanced echocardiography along with the normalization of cholestatic enzymes and improvement of the patient’s conditions. This is the first case of complete reversion of HPS in a non-cirrhotic patient with hepatic granuloma, indicating that intrapulmonary shunt in liver diseases is a functional phenomenon and HPS can be developed even in miscellaneous liver involvement as in this case.

Cirrhotic rats with bacterial translocation have higher incidence and severity of hepatopulmonary syndrome

BACKGROUND

Bacterial translocation, that is, extra-intestinal dissemination of gut bacteria, occurs in approximately 50% of humans and rats with cirrhosis and plays a significant role in enhanced tumor necrosis factor-alpha (TNF-alpha) production. The authors' previous studies have indicated that prevention of bacterial translocation with norfloxacine or inhibition of TNF-alpha with pentoxifylline treatment decreased both the incidence and severity of hepatopulmonary syndrome by attenuating the induction of pulmonary intravascular macrophages in cirrhotic rats. In the present study the hypothesis was tested that the cirrhotic rats with bacterial translocation had higher TNF-alpha production, higher level of sequestration of macrophages in pulmonary vessels, and increased incidence and severity of hepatopulmonary syndrome.

METHODS

Rats were studied 5 weeks after common bile duct ligation or sham operation. Bacterial translocation was defined by positive mesenteric lymph node cultures. Hepatopulmonary syndrome was assessed by measurements of alveoloarterial oxygen difference (AaPO(2)) and intrapulmonary shunt. The TNF-alpha concentration in plasma was measured by ELISA. Pulmonary intravascular macrophage sequestration was assessed by lung morphometric analysis.

RESULTS

Bacterial translocation occurred in 48% of cirrhotic rats. Plasma concentrations of TNF-alpha and the percentage of vessels with pulmonary intravascular macrophages were higher in the cirrhotic rats with bacterial translocation. Rats with bacterial translocation also had a higher incidence (9% vs 63%, P < 0.01) and severity of hepatopulmonary syndrome, as indicated by higher levels of both AaPO(2) and intrapulmonary shunt.

CONCLUSIONS

These results suggest that bacterial translocation may play a role in the pathogenesis of hepatopulmonary syndrome by inducing pulmonary intravascular macrophages through TNF-alpha upregulation.

Patent foramen ovale and the platypnea-orthodeoxia syndrome

The platypnea-orthodeoxia syndrome is a rare but important condition caused by a variety of clinical entities. Several mechanisms have been postulated to cause platypnea and orthodeoxia. These mechanisms mainly involve intracardiac shunting, pulmonary vascular shunting, and ventilation-perfusion mismatching. Patent foramen ovale is an important type of intracardiac shunt that can produce platypnea-orthodeoxia in select patients. Concomitant pulmonary hypertension must be ruled out, but symptoms can occur without pulmonary hypertension in cases with altered intrathoracic anatomy and physiology. Diagnosis usually entails transthoracic or trans-esophageal echocardiogram, ideally with postural provocation by the tilt-table test. Treatment with surgical or percutaneous closure may result in symptomatic relief. The decision to intervene is based mainly on the severity of symptoms and potential morbidities associated with the defect.

Síndrome hepatopulmonar: patogenia, diagnóstico e tratamento

RACIONAL: A síndrome hepatopulmonar é caracterizada por tríade clínica que consiste em: 1) doença hepática e/ou hipertensão portal, 2) dilatações vasculares intra-pulmonares, e 3) anormalidades da oxigenação arterial (pressão parcial de oxigênio <70 mm Hg ou gradiente alvéolo-arterial de oxigênio >20 mm Hg). Sua freqüência varia de acordo com os métodos diagnósticos utilizados. OBJETIVOS: Fazer revisão da literatura sobre patogenia, diagnóstico e tratamento da síndrome hepatopulmonar. MÉTODOS: Levantamento no MEDLINE das publicações nacionais e internacionais mais relevantes sobre a síndrome hepatopulmonar. RESULTADOS: A prevalência da síndrome hepatopulmonar varia de 4% a 17,5%, a depender dos critérios diagnósticos utilizados. A doença hepática associada mais comum é a cirrose. O gradiente alvéolo-arterial de oxigênio parece ser o melhor parâmetro para avaliação das anormalidades da oxigenação arterial. Em relação à detecção das dilatações vasculares intra-pulmonares, a ecocardiografia com contraste é o método de escolha, pois é de fácil realização e pode diferenciar as comunicações intra-pulmonares das intra-cardíacas. No tratamento da síndrome hepatopulmonar, poucos relatos bem sucedidos puderam ser reproduzidos e confirmados utilizando terapia farmacológica e/ou radiologia intervencionista. Atualmente, o transplante de fígado é considerado a principal opção terapêutica desses pacientes, com resultados animadores. CONCLUSÕES: A síndrome hepatopulmonar é uma enfermidade freqüente. Exames gasométricos são necessários para o seu diagnóstico. O transplante de fígado é o tratamento de escolha para os portadores da síndrome.