Hepatopulmonary syndrome. Current concepts in diagnostic and therapeutic considerations

Hepatopulmonary syndrome: diagnosis and treatment

Hepatopulmonary syndrome (HPS) is one of the lung diseases associated with liver cirrhosis and portal hypertension. The diagnosis is based on the triad: liver disease and portal hypertension, evidence of intrapulmonary vascular dilatation and impaired gas exchange. HPS impairs prognosis (23 % survival after 5 years) and patients’ quality of life, so early diagnosis and timely treatment are of great importance. Liver transplantation allows for regression of intrapulmonary vascular dilatation in almost 100 % of cases, normalization of gas exchange and improves a 5-year survival after transplantation from 76 to 87 %. This is the only treatment method indicated for patients with severe HPS, defined by an arterial partial pressure of oxygen (PaO2) below 60 mm Hg. However, in the face of a global shortage of transplants, it is necessary to develop medical therapies to delay or even defer liver transplantation. This goal seems possible due to the growing understanding of the HPS pathophysiology and the development of therapies targeting key mechanisms, mainly inflammatory and angiogenic. This article provides an overview of the clinical manifestations, diagnosis and treatment of HPS based on literature sources from the MEDLINE database on the PubMed platform.

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.

Bilateral Arteriovenous Shunting Through Pial and Perforating Vessels With Multiple Strokes in a Patient With Hepatopulmonary Syndrome

Hepatopulmonary syndrome (HPS) is a condition characterized by chronic liver disease, intrapulmonary arteriovenous shunting, and increased alveolar-arterial oxygen gradient. This case report presents a 54-year-old male patient with a history of stroke, liver cirrhosis, portal vein thrombosis, hypertension, diabetes, and bladder cancer, who presented with worsening headaches and confusion over the course of five years. Digital subtraction angiogram (DSA) revealed multiple bilateral arteriovenous shunts, suggesting a shunting mechanism similar to that observed in HPS. We propose that this unique case could provide valuable insights into the parallels between the pathophysiology of HPS and diffuse arteriovenous shunting in the brain and the increased risk of ischemic and hemorrhagic events in both cases. Further studies are needed to establish a clearer understanding of this relationship and its implications for patients with chronic liver disease.

Advances in Diagnostic Imaging of Hepatopulmonary Syndrome

Hepatopulmonary syndrome (HPS) is a serious pulmonary complication of progressive liver disease that leads to a poor clinical prognosis. Patients with HPS may develop acute respiratory failure, which requires intensive care and therapy. At present, the only effective treatment is liver transplantation; therefore, early diagnosis and timely treatment are of considerable significance. The three main features of HPS are liver disease, oxygenation disorder, and intrapulmonary vascular dilatation (IPVD). Diagnosing HPS is challenging due to the difficulty in detecting the presence or absence of IPVD. As such, imaging examination is very important for detecting IPVD. This paper reviews the imaging methods for diagnosing HPS such as ultrasound, dynamic pulmonary perfusion imaging, pulmonary angiography, and computed tomography.

Non-invasive assessment of intrapulmonary shunt and ventilation to perfusion ratio in children with hepatopulmonary syndrome before and after liver transplantation

OBJECTIVES

To use the oxyhaemoglobin dissociation curve (ODC) to non-invasively measure the ventilation perfusion ratio (V_A/Q) and right-to-left intrapulmonary vascular shunt before and after liver transplantation (LT) in children with hepatopulmonary syndrome (HPS). To investigate whether the right-to-left shunt derived by ODC correlated with the shunt derived by technetium-99 labelled macroaggregated albumin lung perfusion scan (MAA).

METHODS

A retrospective cohort study at King's College Hospital NHS Foundation Trust, London, UK was performed between 1998 and 2016. The V_A/Q and right-to-left shunt were non-invasively measured pre and post LT. The pre-LT right-to-left intrapulmonary shunt was also measured by MAA. The non-invasively derived pre-LT shunt was correlated with the shunt derived by MAA.

RESULTS

Fifteen children with HPS were studied with a median (IQR) age at LT of 8.8 (6.6-12.9) years. The median (IQR) pre-LT V_A/Q [0.49 (0.42-0.65)] was lower compared to the post-LT V_A/Q [0.61 (IQR 0.54-0.72), p = 0.012]. The median (IQR) pre-LT shunt was 19 (3-24) % which decreased to zero in all but one children post-LT, (p = 0.001). The MAA-derived shunt was significantly positively correlated with the ODC-derived shunt (r = 0.783, p = 0.001). The mean (SD) difference between shunt derived by ODC and shunt derived by MAA was 0.5 (7.2) %.

CONCLUSIONS

Ventilation/perfusion impairment reverses but not completely resolves after liver transplantation in children with hepatopulmonary syndrome. The non-invasive method for estimating intrapulmonary shunting could be used as an alternative to the macroaggregated albumin scan in this population.

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.

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.

Time-dependent reversal of significant intrapulmonary shunt after liver transplantation

BACKGROUND/AIMS

Although the association between intrapulmonary shunt (IPS) and liver cirrhosis is clear, data of repeated contrast echocardiography (CE) before and after liver transplantation (LT) to evaluate factors associated with IPS are limited.

METHODS

Hand-agitated saline was used for CE and, by assessing left-chamber opacification, IPS was classified as grade 0 to 4. Grade 3/4 constituted significant IPS and hepatopulmonary syndrome (HPS) was defined as significant IPS with the arterial partial pressure of oxygen < 70 mmHg.

RESULTS

Before LT, 253 patients underwent CE and the frequency of significant IPS and HPS were 44% (n = 112) and 7% (n = 17), respectively. Child-Pugh score (odds ratio [OR], 1.345; 95% confidence interval [CI], 1.090 to 1.660; p = 0.006) and arterial oxygen content (OR, 0.838; 95% CI, 0.708 to 0.991; p = 0.039) were independent determinants of significant IPS, whereas direct bilirubin (OR, 1.076; 95% CI, 1.012 to 1.144; p = 0.019) was the only variable associated with HPS. Among 153 patients who underwent successful LT, repeated CE was performed in 97 (63%), which showed significant reductions in IPS grade (from 2.6 ± 1.0 to 1.2 ± 1.3, p < 0.001) and the prevalence of significant IPS (from 56% to 20%, p = 0.038). After adjustment for pre-LT IPS grade, time from LT to repeated CE presented negative linear relationship with post-LT IPS grade (r 2 = 0.366, p < 0.001) and was the only determinant of post-LT IPS grade (OR, 1.009; 95% CI, 1.003 to 1.014; p = 0.004).

CONCLUSION

Repeated CE is useful to evaluate intrapulmonary vascular change before and after LT. Reversal of IPS after successful LT is time-dependent and follow-up duration should be considered for accurate assessment of IPS after LT.

Hepatopulmonary Syndrome: Oxidative Stress and Physical Exercise

Hepatopulmonary syndrome (HPS) may be defined by hepatic disease, gas exchange abnormalities that may lead to hypoxaemia, and the presence of pulmonary vascular dilations. The balance between the many substances involved in vasodilation and vasoconstriction is regulated by the liver; thus, liver damage may generate systemic changes throughout the body. The pulmonary tissue may be damaged by reactive oxygen species or nitric oxide. Dyspnoea is the most frequent pulmonary symptom, caused by tissue damage, and may become worse when an individual exercises. In experimental research the surgical model of bile duct ligation is the optimal model to simulate the typical lung alterations present in HPS, which results in an increase in oxidative stress in hepatic and pulmonary tissues. In liver injury, the muscular system may also be damaged, for example sarcopenia may seriously aggravate cirrhosis and is associated with cirrhotic patient mortality. Muscular changes can be explained by the actions of myostatin and insulin-like growth factor and the increase in body levels of ammonia. As a result of impaired cardiopulmonary and muscular conditions, HPS patients may exhibit a low exercise tolerance, low muscle strength, and low functionality. Liver disease can contribute to HPS oxidative stress and is one of the main factors responsible for the reduction of gas exchange. Physical exercise can be performed as a way of modifying this pathophysiological state. Studies that have investigated physical exercise as a therapy for cirrhosis suggest that this approach may be beneficial for cirrhotic patients, primarily with regard to muscular and cardiorespiratory injuries.

Differential diagnosis of hepatopulmonary syndrome (HPS): Portopulmonary hypertension (PPH) and hereditary hemorrhagic telangiectasia (HHT)

Hepatopulmonary syndrome (HPS) is a severe complication of advanced liver disease associated with an extremely poor prognosis. HPS is diagnosed in 4-47% of patients with cirrhosis and in 15-20% of candidates for liver transplantation. In addition, severe hypoxia is associated with a high risk of complications of liver transplantation (a 30% chance during the first 90 days) and increases the gap between transplantation and improving arterial oxygenation. The pathogenesis of HPS is not fully understood, and no effective pharmacological treatment has been developed yet. Currently, the treatment of choice for HPS is orthotopic liver transplantation. Non-specific clinical criteria and the lack of standardized diagnostic criteria for determining HPS can lead to diagnostic errors. Portopulmonary hypertension and hereditary hemorrhagic telangiectasia, also known as Osler-Weber-Rendu syndrome, are pulmonary complications of liver disease which should be differentially diagnosed from HPS.

Left Ventricular Dilation and Pulmonary Vasodilatation after Surgical Shunt for Treatment of Pre-Sinusoidal Portal Hypertension

Objective

The aim of this study was to prospectively investigate the long-term cardiovascular and pulmonary hemodynamic effects of surgical shunt for treatment of portal hypertension (PH) due to Schistosomiasis mansoni.

Location

The University of São Paulo Medical School, Brazil; Public Practice.

Methods

Hemodynamic evaluation was performed with transesophageal Doppler and contrast-enhanced echocardiography (ECHO) on twenty-eight participants with schistosomal portal hypertension. Participants were divided into two groups according to the surgical procedure used to treat their schistosomal portal hypertension within the last two years: group 1—distal splenorenal shunt (DSRS, n = 13) and group 2—esophagogastric devascularization and splenectomy (EGDS, n = 15).

Results

The cardiac output (5.08 ± 0.91 L/min) and systolic volume (60.1 ± 5.6 ml) were increased (p = 0.001) in the DSRS group. DSRS participants had a significant increase (p < 0.0001) in their left ventricular end-systolic and end-diastolic diameters as well as in their left ventricular end-diastolic and end-systolic volumes (p < 0.001) compared with the preoperative period. No statistically significant difference was found in the patients who underwent EGDS. ECHO revealed intrapulmonary vasodilatation (IPV) in 18 participants (64%), 9 DSRS and 9 EGDS (p > 0.05).

Conclusions

The late increase in the cardiac output, stroke volume and left ventricular diameters demonstrated left ventricular dilatation after a distal splenorenal shunt. ECHO revealed a greater prevalence for IPV in patients with schistosomiasis than has previously been described in patients with PH from liver cirrhosis.

Hepatopulmonary Syndrome and Liver Transplantation: A Recent Review of the Literature

A severe and common pulmonary vascular complication of liver disease is hepatopulmonary syndrome (HPS). It is a triad of liver dysfunction and/or portal hypertension, intrapulmonary vascular dilatations, and increased alveolar-arterial oxygen gradient. Prevalence varies according to various study groups from 4%-47%. While the most common presenting symptom of HPS is dyspnea, it is usually asymptomatic, and thus all liver transplant candidates should be screened for its presence. Pulse oximetry is a useful screening method, but arterial blood gas examination is the gold standard. If there is an abnormal P (A-a)O2 gradient, microbubble transthoracic echocardiography should be done for diagnosis. Outcome is unpredictable, and there is currently no effective medical therapy. The only effective therapy is considered to be liver transplantation. Complete resolution of HPS after liver transplantation is seen within a year in most HPS patients.

Role of angiogenic factors/cell adhesion markers in serum of cirrhotic patients with hepatopulmonary syndrome

BACKGROUND & AIMS

Hepatopulmonary syndrome is a complication of chronic liver disease resulting in increased morbidity and mortality. It is caused by intrapulmonary vascular dilations and arteriovenous connections with devastating influence on gas exchange. The pathogenesis is not completely understood but evidence mounts for angiogenesis. Aims of this study were to identify angiogenic factors in serum of patients with hepatopulmonary syndrome and to study the possibility to predict its presence by these factors.

METHODS

Multiplex assays were used to measure the concentration of angiogenic factors in patients with (n = 30) and without hepatopulmonary syndrome (n = 30). Diagnosis was based on the presence of gas exchange abnormality and intrapulmonary vasodilations according to published guidelines.

RESULTS

Patients with and without hepatopulmonary syndrome had similar MELD scores (median: 11.2 vs. 11.6; P = 0.7), Child-Pugh score (P = 0.7) and PaCO2 values (median: 35 vs. 37; P = 0.06). PaO2 and P(A-a) O2 gradient were significantly different (respectively median of 80 vs. 86, P = 0.02; and 24 vs. 16, P = 0.004). Based on area under the curve (AUC) data and P-values, the best predictors were vascular cell adhesion molecule 1 (VCAM1) (AUC = 0.932; P < 0.001) and intercellular adhesion molecule 3 (ICAM3) (AUC = 0.741; P = 0.003). Combining these factors results in an AUC of 0.99 (after cross-validation still 0.99).

CONCLUSIONS

VCAM1 and ICAM3 might be promising biomarkers for predicting hepatopulmonary syndrome. Combining these factors results in an AUC of 0.99 and a negative predictive value of 100%. Determining the concentration of these biomarkers might be a screening method to detect hepatopulmonary syndrome. The use of these biomarkers should be validated in larger groups of patients.

The effects of flavanoid on the treatment of hepatopulmonary syndrome

Purpose

Hepatopulmonary syndrome is an arterial oxygenation disorder brought about by advanced liver failure and pulmonary vascular dilatations. The reason why hypoxia develops in hepatopulmonary syndrome depends on the broadening of perialveolar capillary veins. Our study aims to investigate the effects of Flavanoid on hepatopulmonary syndrome through its inhibition of nitric oxide.

Methods

Three groups, each having 8 rats, were formed within the scope of our study. Group I (the control group) only received laparatomy, group II received choledoch ligation, and group III was administered Flavanoid (90% flavonoid diosmin, 10% flavonoid hesperidin) following choledoch ligation. The rats were administered Flavanoid at week two following choledoch ligation. The rats' livers and lungs were examined histopathologically following a five-week follow-up and the perialveolar vein diameters were measured. Arterial blood gases and biochemical parameters were evaluated.

Results

It was seen that fibrosis and oxidative damage in the liver with obstructive jaundice as well as hypoxia with pulmonary perialveolar vein sizes were significantly lower than the other group with cirrhosis formed through the administration of Flavanoid.

Conclusion

We have concluded that Flavanoid administration might be useful in the treatment of hypoxia in hepatopulmonary syndrome and the delay of cirrhosis contraction.

Parenchymal alterations in cirrhotic livers in patients with hepatopulmonary syndrome or portopulmonary hypertension

Hepatopulmonary syndrome (HPS) and portopulmonary hypertension (PPH) are distinct pulmonary vascular complications of cirrhosis. Little is known about possible associated hepatic histopathological features. Explanted livers from patients clinically diagnosed with HPS (n = 8) or PPH (n = 7) and cirrhotic explants from controls (n = 30) without HPS or PPH were evaluated with trichrome histochemistry, anti-glutamine synthetase (anti-GS), and anti-CD34 immunohistochemistry (IHC). Trichrome stains were characterized by cirrhotic nodules (CNs) of various sizes, including incomplete septal cirrhosis (ISC). ISC was overrepresented in the HPS (4/8 or 50%) and PPH livers (3/7 or 43%); in addition, neither group had micronodular cirrhosis. The control explants showed the entire spectrum of nodules: micronodular, macronodular, mixed CNs, and ISC (P = 0.04). The variability of cirrhosis severity was shown with the Laennec grading system (0-6). The cirrhosis of the majority of the HPS (6/8) and PPH livers (6/7) was scored as mild, whereas the control explants were more evenly distributed across the mild (14/30) and moderate/severe grades (16/30). GS positivity was retained in a perivenular location as the dominant pattern in each explant group. CD34 staining detected capillarized sinusoids of CNs as well as vascular channels within septa, but no significant differences were found between the groups. None of the observed light microscopy or histochemistry and IHC patterns showed a correlation with the underlying liver disease. Although our results demonstrate variable architectural and vascular remodeling within and between explant livers regardless of the presence or types of pulmonary complications, there were differences in explants with HPS or PPH versus controls that correlated with less severe cirrhosis.

Response to exercise in patients with liver cirrhosis: implications for liver transplantation

End-stage liver cirrhosis is a systemic disease carrying a short-term desperate prognosis without liver transplantation. Given the discrepancy between the growing number of candidates and the limited available liver grafts, the pre-transplantation screening process has become a challenging task. Cardiopulmonary exercise testing, by measuring maximal oxygen consumption at peak exercise, provides a global integrative approach of the health status of an individual. In the setting of liver cirrhosis, decreased oxygen consumption at peak exercise may result from a combination of multiple extra-hepatic complications, including deconditioning, malnutrition-associated muscle weakness, anaemia, cirrhotic cardiomyopathy, and hepato-pulmonary syndrome for instance. In addition, oxygen consumption at peak exercise not only correlated with the severity of the liver disease, but it is also independently associated with survival following liver transplantation. The present article aims to review the numerous determinants of impaired aerobic capacity in patients with severe liver disease, and to discuss how useful is cardiopulmonary exercise testing as a critical tool in the pre-transplantation assessment of these 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.

Cerebral lipiodol embolism after transarterial chemoembolization for hepatic carcinoma: A case report

We report a case of cerebral lipiodol embolism (CLE) after transarterial chemoembolization (TACE) for unresectable hepatic carcinoma (HCC). A 54-year-old man with unresectable HCC underwent TACE via the right hepatic artery and right inferior phrenic artery using a mixture of 40 mg pirarubicin and 30 mL lipiodol. His level of consciousness deteriorated after TACE, and non-contrast computed tomography revealed a CLE. The cerebral conditions improved after supportive therapy. The complication might have been due to hepatic arterio-pulmonary vein shunt caused by direct invasion of the tumor. Even though CLE is an uncommon complication of TACE, we should be aware of these rare complications in patients with high risk factors.

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.

The end-organ impairment in liver cirrhosis: appointments for critical care

Liver cirrhosis (LC) can lead to a clinical state of liver failure, which can exacerbate through the course of the disease. New therapies aimed to control the diverse etiologies are now more effective, although the disease may result in advanced stages of liver failure, where liver transplantation (LT) remains the most effective treatment. The extended lifespan of these patients and the extended possibilities of liver support devices make their admission to an intensive care unit (ICU) more probable. In this paper the LC is approached from the point of view of the pathophysiological alterations present in LC patients previous to ICU admission, particularly cardiovascular, but also renal, coagulopathic, and encephalopathic. Infections and available liver detoxifications devices also deserve mentioning. We intend to contribute towards ICU physician readiness to the care for this particular type of patients, possibly in dedicated ICUs.

Detection of hepatopulmonary syndrome in patients with liver cirrhosis using 3D contrast echocardiography

BACKGROUND AND STUDY AIMS

Hepatopulmonary syndrome (HPS) is characterised by the triad of advanced liver disease, arterial hypoxaemia and intrapulmonary vascular dilatation (IPVD). The present study aimed to evaluate HPS in patients with liver cirrhosis and the role of three-dimensional (3D) contrast echocardiography in the detection of this syndrome.

PATIENTS AND METHODS

A total of 78 chronic liver disease patients aged 42 ± 11 years fulfilled the criteria for this study and were subjected to clinical examination, laboratory investigations, arterial blood gases measurement, pulmonary function tests, upper gastrointestinal endoscopy, 3D contrast echocardiography and computed tomography (CT) pulmonary angiography.

RESULTS

According to 3D contrast echocardiography results, we divided the patients into a positive group (n=26) in which patients showed a delayed appearance of contrast in left heart chambers and a negative group (n=52). Among 26 patients of the positive group, nine had hypoxaemia (partial pressure of oxygen (PaO(2)) <70 mm Hg) and were diagnosed as having hepatopulmonary syndrome (HPS), the other 17 who had shown echocardiographic evidence of IPVDs but without hypoxaemia were diagnosed as having sub-clinical HPS. This study showed significant correlation between positive contrast echocardiography findings and duration of liver disease, Child score, cyanosis, clubbing, orthodeoxia, portal vein diameter, spleen size and oesophageal varices grades. No significant correlation was found between 3D contrast echocardiography findings and age, sex, spider naevi and pulmonary function tests. Multivariate logistic regression showed that cyanosis, clubbing, orthodeoxia, Child score and portal vein diameter are independent predictors of HPS.

CONCLUSION

Cyanosis, clubbing and platypnoea-orthodeoxia are suggestive indicators of HPS, which can be easily detected by 3D contrast echocardiography which can replace the trans-oesophageal echocardiogram (TEE) in cirrhotic patients.

Clinical manifestations of portal hypertension

The portal hypertension is responsible for many of the manifestations of liver cirrhosis. Some of these complications are the direct consequences of portal hypertension, such as gastrointestinal bleeding from ruptured gastroesophageal varices and from portal hypertensive gastropathy and colopathy, ascites and hepatorenal syndrome, and hypersplenism. In other complications, portal hypertension plays a key role, although it is not the only pathophysiological factor in their development. These include spontaneous bacterial peritonitis, hepatic encephalopathy, cirrhotic cardiomyopathy, hepatopulmonary syndrome, and portopulmonary hypertension.

Cardiopulmonary response to exercise in patients with liver cirrhosis and impaired pulmonary gas exchange

Maximal exercise capacity and pulmonary gas exchange are both commonly impaired in liver cirrhosis. Apart from rare cases of hepatopulmonary syndrome, it is still unknown whether these moderate pulmonary gas exchange abnormalities can alter aerobic capacity of cirrhotic patients. Resting pulmonary function tests and symptom-limited cardiopulmonary exercise testing were prospectively investigated in 30 patients with liver cirrhosis exhibiting a widened alveolar-arterial oxygen gradient (P(A-a)O(2) > 30 mm Hg at peak exercise) without pulmonary vascular dilatations at contrast-enhanced echocardiography. Data were compared with those of 30 normoxemic cirrhotic controls (matched for age, gender, body mass index, etiology and severity of liver disease, smoking habits, hemoglobin level, and beta-blocker therapy). Resting cardiopulmonary parameters were within normal range in both groups except carbon monoxide lung transfer (TLCO, 60.4 ± 2.9 vs 74.3 ± 2.8% in controls, p = 0.0004) and P(A-a)O(2) (28.8 ± 2 vs 15.3 ± 2 mm Hg in controls, p < 0.0001). Cirrhotics with impaired gas exchange during exercise exhibited a significant reduction in maximal oxygen uptake (VO(2)max, 1.18 ± 0.07 (53% predicted) vs 1.41 ± 0.07 L/min (62% predicted), p = 0.004), a higher ventilation level at ventilatory threshold (V(E)/VO(2), 39.2 ± 1.5 vs 35.3 ± 1.5, p = 0.01) without ventilatory limitation, and a greater dead space to tidal volume ratio (V(D)/V(T)max, 0.32 ± 0.01 vs 0.25 ± 0.01, p = 0.01). VO(2)max correlates negatively with V(D)/V(T)max (r(2) = 0.36; p < 0.0001). There were no differences in cardiac or metabolic response to exercise between groups. Taken together these findings suggest that clinically undetectable pulmonary vascular disorders can slightly contribute to further reduce exercise capacity of cirrhotic patients.

Pulmonary vascular complications of chronic liver disease: Pathophysiology, imaging, and treatment

To review the pathogenesis of pulmonary vascular complications of liver disease, we discuss their clinical implications, and therapeutic considerations, with emphasis on potential reversibility of the hepatopulmonary syndrome after liver transplantation. In this review, we also discuss the role of imaging in pulmonary vascular complications associated with liver disease.

Venous air embolism and intracardiac thrombus after pressurized fibrin glue during liver surgery

After segmental liver resection, a fibrin glue aerosol was used to stop diffuse bleeding from the liver resection site. Immediately after pressurized administration, severe hypotension and bradycardia occurred, requiring cardiopulmonary resuscitation and inotropic support. Transoesophageal echocardiography demonstrated air in both ventricles deriving from the inferior vena cava; contractility of both ventricles was markedly reduced. In addition, a 3 cm floating thrombus was detected in the right ventricle. This case demonstrates that sprayed fibrin glue can cause life-threatening air embolism and intracardiac thrombus formation in liver surgery.

Cardiovascular changes in cirrhosis: pathogenesis and clinical implications

Liver cirrhosis is associated with a wide range of cardiovascular abnormalities including hyperdynamic circulation, cirrhotic cardiomyopathy, and pulmonary vascular abnormalities. The pathogenic mechanisms of these cardiovascular changes are multifactorial and include neurohumoral and vascular dysregulations. Accumulating evidence suggests that cirrhosis-related cardiovascular abnormalities play a major role in the pathogenesis of multiple life-threatening complications including hepatorenal syndrome, ascites, spontaneous bacterial peritonitis, gastroesophageal varices, and hepatopulmonary syndrome. Treatment targeting the circulatory dysfunction in these patients may improve the short-term prognosis while awaiting liver transplantation. Careful fluid management in the immediate post-transplant period is extremely important to avoid cardiac-related complications. Liver transplantation results in correction of portal hypertension and reversal of all the pathophysiological mechanisms that lead to the cardiovascular abnormalities, resulting in restoration of a normal circulation. The following is a review of the pathogenesis and clinical implications of the cardiovascular changes in cirrhosis.

Prolonged paradoxical air embolism during intraoperative intestinal endoscopy confirmed by transesophageal echocardiography -A case report-

Venous air embolism (VAE) during intestinal endoscopy is a rare complication. We report a case of cardiovascular collapse due to VAE confirmed by transesophageal echocardiography (TEE) during intraoperative intestinal endoscopy. TEE detected air bubbles in the left ventricle up to 1 hour after the event. When a patient deteriorates during endoscopic procedures, VAE and possible paradoxical air embolism (PAE) should be suspected. This case demonstrates that TEE can play an important role in diagnosing and managing an air embolism in anesthetized patients. In addition, this case demonstrates that PAEs may occur longer than expected after recovery from VAE-induced cardiovascular collapse.

Effect of chronic methylene blue administration on hypoxemia in rats with common bile duct ligation

AIM

Acute administration of methylene blue (MB) can reverse hypoxemia in patients with hepatopulmonary syndrome (HPS). We evaluated the effect of chronic MB administration in common bile duct-ligated rats, which develop HPS by 5 weeks after surgery.

METHODS

A total of 96 Sprague-Dawley rats were used, including 63 rats with common bile duct ligation (CBDL), 22 sham-operated rats and 11 normal control rats. MB (6 mg/kg) was injected s.c. once a day for 4 weeks. Evaluation of hemodynamics and intrapulmonary vascular dilatation (IPVD), as well as blood sampling for arterial blood gas analysis, were done under conscious and unrestrained conditions. Hemodynamics were assessed by the reference sample method using (141)Ce-microspheres (15 microm in diameter), and IPVD was also determined by i.v. injection of these microspheres. Histological examination of the lungs was done with hematoxylin-eosin staining and immunohistochemical staining for von Willebrand factor or vascular endothelial growth factor.

RESULTS

Both the arterial oxygen tension and alveolar-arterial oxygen difference were significantly improved in MB-treated CBDL rats. The hyperdynamic circulation and splanchnic hyperemia seen in untreated CBDL rats were also alleviated by MB treatment. However, IPVD was not affected by MB. Histological examination of the lungs indicated that MB treatment reduced the proliferation of alveolar capillary vessels and angiogenesis, leading to improvement of arterial dysoxygenation. Hepatic synthetic and detoxification functions, as well as renal function, were not altered by MB treatment.

CONCLUSION

Methylene blue may be a candidate treatment for HPS that does not cause deterioration of hepatic or renal function.

Long-term outcome and management of hepatopulmonary syndrome in children

We aim to report a single center experience of the management and long term outcome of HPS in pediatric liver transplant recipients. A retrospective review of children with HPS from 1990 to 2004.

INCLUSION CRITERIA

liver disease or portal hypertension, hypoxemia (PaO(2) < 70 mmHg or SaO(2) < 95%) and intrapulmonary shunting documented by macroaggregated albumin scan ratio of >4% (classified mild group [<20%], moderate group [20-40%] and severe group [>40%]). Resolution of HPS post-liver transplant was defined as PaO(2) > 70 mmHg or SaO(2) > 95%. Eighteen children (six male [34%], median age at diagnosis of HPS 8.6 [1-15.5] yr) had HPS: biliary atresia (n = 8), idiopathic biliary cirrhosis (n = 4), progressive intrahepatic cholestasis (n = 2), miscellaneous (n = 4). The majority had mild shunting (n = 8). Fourteen underwent transplantation with resolution of HPS in 13. Six developed complications: hepatic artery thrombosis (n = 4), biliary (n = 2). Four children died (28%), two pretransplant. There was a tendency towards shunt fraction worsening to a slower degree over time. One-yr survival rate post-transplant was 93%. Median PaO(2) was significantly lower in non-survivors compared to survivors (43 vs. 55.2 mmHg, p = 0.03). There was correlation between oxygen parameters pretransplant and time to HPS resolution post-transplant. HPS is reversible after transplant, but is associated with increasing mortality and morbidity.

The role of garlic in hepatopulmonary syndrome: a randomized controlled trial

BACKGROUND

Increased nitric oxide production in cirrhosis has been commonly implicated in the genesis of hepatopulmonary syndrome (HPS). Initial studies suggested that garlic, a constituent of the daily diet, may have a role in the treatment of HPS by altering nitric oxide production.

OBJECTIVE

To evaluate the effects of oral garlic supplementation on arterial blood gas parameters, and overall morbidity and mortality in patients with HPS.

METHODS

Twenty-one and 20 HPS patients were randomly assigned to receive either oral garlic supplementation or placebo, respectively, and were evaluated monthly over a period of nine to 18 months.

RESULTS

After nine months, garlic supplementation was associated with a 24.66% increase in baseline arterial oxygen levels (83.05 mmHg versus 66.62 mmHg; P<0.001), compared with only a 7.37% increase (68.75 mmHg versus 64.05 mmHg; P=0.02) among subjects in the placebo group. There was also a 28.35% decrease in alveolar-arterial oxygen gradient (21.35 mmHg versus 29.77 mmHg; P<0.001) among patients with HPS who received garlic, in contrast with only a 10.73% decrease (29.11 mmHg versus 32.61 mmHg; P=0.12) among those in the placebo group. After nine months, the arterial oxygen level was significantly higher (83.05 mmHg versus 68.75 mmHg; P<0.001) and the alveolar-arterial oxygen gradient was significantly lower (21.35 mmHg versus 29.11 mmHg; P<0.001) among patients receiving garlic compared with those receiving placebo. Reversal of HPS was observed in 14 of 21 patients (66.67%) on garlic supplementation (intent-to-treat analysis) and in one of 20 patients (5%) on placebo. Two of 21 patients undergoing garlic supplementation died during follow-up in contrast to seven of 20 patients who were on placebo.

CONCLUSIONS

Garlic supplementation may be beneficial in patients with HPS for the reversal of intrapulmonary shunts as well as reducing hypoxemia and mortality.

Cerebral lipiodol embolism following transcatheter arterial chemoembolization for hepatocellular carcinoma

Cerebral lipiodol embolism (CLE) is an extremely rare complication of transcatheter arterial chemoembolization for hepatocellular carcinoma (HCC). The authors present a case of CLE that occurred after the second hepatic arterial chemoembolization for HCC, and attempt to introduce several plausible mechanisms of CLE, after reporting the clinical and radiological findings and reviewing the medical literature.

Hepatopulmonary syndrome and portopulmonary hypertension

The pulmonary complications of end-stage liver disease include hepatopulmonary syndrome and portopulmonary hypertension. The etio-pathogenesis of these conditions is as yet unclear. Hepatopulmonary syndrome is a gas exchange abnormality and usually manifests as hypoxemia secondary to intra-pulmonary vascular shunts. These shunts can be demonstrated by echocardiography using agitated saline injections, and quantitated by lung perfusion scans. Liver transplantation is the treatment of choice for hepatopulmonary syndrome, and there are no effective pharmacological therapies. Portopulmonary hypertension is a hemodynamic problem which manifests as fatigue and right sided cardiac failure. Several vasoactive agents have been used to lower mean pulmonary arterial pressures. Portopulmonary hypertension is a relative contraindication to liver transplantation.

Hepatopulmonary syndrome in patients with Schistosoma mansoni periportal fibrosis

Hepatopulmonary syndrome (HPS) is characterized by the presence of liver disease, arterial hypoxemia and intrapulmonary vascular dilatation (IPVD). IPVD includes diffused or localized dilated pulmonary capillaries and, less commonly, pleural and pulmonary arteriovenous communications. The aim of the present study was to investigate the occurrence of HPS in patients with Schistosoma mansoni periportal fibrosis in treatment at a university hospital in northeastern Brazil.

PATIENTS AND METHODS

Eighty-four patients were enrolled in the study between April and July 2007 and underwent arterial blood gas analysis. Patients with an alveolar-arterial oxygen gradient (DA-aO(2)) > or = 15 mmHg were submitted to contrast-enhanced transthoracic echocardiogram (CE-TTE) with saline microbubbles. The diagnostic criterion for HPS was DA-aO(2) > or = 15 mmHg associated to IPVD, as identified through CE-TTE. Patients with HPS underwent contrast-enhanced 16-channel multidetector-row computed tomography (MDCT) of the thorax.

RESULTS

Twenty-two patients (26.19%) had DA-aO(2) > or = 15 mmHg (mean value=20.86+/-7.91). CE-TTE was positive for IPVD in five of the 22 patients with DA-aO(2) > or = 15 mmHg and all these patients had hepatosplenic disease, revealing a 6% prevalence of HPS (CI: 1.96-13.35) in the overall population of 84 patients, with a 10.2% prevalence in the group with hepatosplenic disease. The following were the 16-channel MDCT findings in these five patients: dilated peripheral pulmonary vasculature (100%); ratio of segmental arterial diameter to adjacent bronchial diameter equal to or greater than 2:1 (100%); higher number of visible terminal vessel branches in lung dependent regions (40%); and micronodules associated with subpleural surface centrilobular vessels (40%). No patient had evidence of arteriovenous fistula. These findings reveal that HPS occurs (usually in a mild form) in patients with Schistosoma mansoni periportal fibrosis and portal hypertension seems to be an important factor related to the occurrence of HPS in such cases.

Hepatopulmonary syndrome: an update

Hepatopulmonary syndrome (HPS) is a clinical threesome composed of liver disease, intrapulmonary vascular dilatation (IPVD) and arterial gas abnormalities. Its occurrence has been described in up to 32% of cirrhotic candidates for liver transplantation. It also affects non-cirrhotic patients with portal hypertension. Its pathogenesis is not well defined, but an association of factors such as imbalance in the endothelin receptor response, pulmonary microvascular remodeling and genetic predisposition is thought to lead to IPVD. Diagnosis is based on imaging methods that identify these dilatations, such as contrast echocardiography or perfusion scintigraphy with 99mTc, as well as analysis of arterial gases to identify elevated alveolar-arterial differences in O2 or hypoxemia. There is no effective pharmacological treatment and complete resolution only occurs through liver transplantation. The importance of diagnosing HPS lies in prioritizing transplant candidates, since presence of HPS is associated with worse prognosis. The aim of this paper was to review the pathogenetic theories and current diagnostic criteria regarding HPS, and to critically analyze the prioritization of patients with HPS on the liver transplant waiting list. Searches were carried out in the Medline (Medical Literature Analysis and Retrieval System Online) via PubMed, Cochrane Library and Lilacs (Literatura Latino-Americana e do Caribe em Ciências da Saúde) databases for articles published between January 2002 and December 2007 involving adults and written either in English or in Portuguese, using the term hepatopulmonary syndrome. The studies of greatest relevance were included in the review, along with text books and articles cited in references that were obtained through the review.