The hepatopulmonary syndrome: new name, old complexities

Pulmonary dysfunction in non-cirrhotic patients with chronic viral hepatitis

Background: Hepatopulmonary syndrome (HPS), defined as hypoxemia and functional intrapulmonary right-to-left shunts in the presence of chronic liver disease, is a frequent complication of end-stage liver disease. The aim of this study was to determine the extent of pulmonary dysfunction and the prevalence of HPS in non-cirrhotic patients with chronic viral hepatitis. Methods: Lung function tests were carried out in 178 patients with chronic viral hepatitis (mean age 43.2 years, 95 smokers). To demonstrate intrapulmonary shunting, contrast echocardiography was performed in all patients with hypoxemia (paO(2)<70 mmHg) or a reduced diffusion capacity (DLCO<70% predicted). Results: The median results of lung function parameters (FVC, FEV(1), FEV(1)/FVC, TLC, DLCO, and blood gas analysis) were normal. Despite normal lung function, hypoxemia and/or DLCO reduction were observed in 17 of 178 patients (9.6%). A correlation with inflammatory activity, extent of fibrosis, or etiology was not found. Intrapulmonary shunting was observed in three of 17 patients. Two of these patients fulfilled the diagnostic criteria of HPS. Conclusions: Impaired gas exchange is a common finding even in non-cirrhotic patients with chronic viral hepatitis. HPS, however, was present in 1.1% of patients with chronic viral hepatitis and is thus not restricted to patients with liver cirrhosis, portal hypertension, or acute liver failure.

Occurrence of hepatopulmonary syndrome in Budd-Chiari syndrome and the role of venous decompression

BACKGROUND & AIMS

Hepatopulmonary syndrome (HPS) has been predominantly detected in cirrhotic patients and rarely in patients with noncirrhotic portal hypertension. The aim of this study was to determine the occurrence of HPS in patients with Budd-Chiari syndrome (only anecdotal reports available) and evaluate the role of venous decompression in its reversal.

METHODS

Twenty-nine consecutive cases of Budd-Chiari syndrome without primary cardiopulmonary disease were investigated by air contrast echocardiography and arterial blood gas analysis. Venous decompression (e.g., by balloon cavoplasty) was attempted when feasible.

RESULTS

Eight cases (27.6%) of HPS and 9 cases (31.0%) with positive contrast echocardiography but unimpaired oxygenation were detected. Duration of disease was longer (P = 0.026) among those with positive contrast echocardiography. Cavoplasty reversed 4 of 5 cases of HPS and 2 of 2 cases with positive contrast echocardiography alone. Venous decompression by drainage of amebic liver abscess (which was compressing hepatic venous outflow) also reversed 1 case of HPS. HPS was relieved by venous decompression in 5 of 6 cases.

CONCLUSIONS

HPS developed in a substantial fraction of our patients with Budd-Chiari syndrome, with positive contrast echocardiography occurring mainly in the benign, slowly progressing variety. Venous decompression showed promise in reversing such cases.

Utility of pulse oximetry in the detection of arterial hypoxemia in liver transplant candidates

Hepatopulmonary syndrome, arterial hypoxemia caused by intrapulmonary vasodilatation, occurs in approximately 10% of patients with cirrhosis. The severity of hypoxemia affects liver transplant candidacy and is associated with increased morbidity and mortality posttransplantation. Screening guidelines for detecting the presence of arterial hypoxemia do not exist. The aim of this study is to investigate the accuracy and utility of pulse oximetry in the detection of hypoxemia (PaO(2) < 70 mm Hg) in patients with cirrhosis. Two hundred prospective liver transplant candidates were compared with 94 controls. Arterial oxyhemoglobin saturation was obtained by pulse oximetry (SpO(2)) and compared with simultaneous arterial blood gas (ABG) oxyhemoglobin values (SaO(2); bias = the difference). PaO(2), carboxyhemoglobin, methemoglobin, and routine clinical and biochemical parameters were investigated to account for the bias. SpO(2) overestimated SaO(2) in 98% of patients with cirrhosis (mean bias, 3.37%; range, -1% to 10%). Forty-four percent of patients with cirrhosis and controls had a bias of 4% or greater. No clinical or biochemical parameters of cirrhosis accounted for the overestimation of pulse oximetry. Twenty-five subjects with cirrhosis were hypoxemic, and an SpO(2) of 97% or less showed a sensitivity of 96% and a positive likelihood ratio of 3.9 for detecting hypoxemia. An SpO(2) of 94% or less detected all subjects with an arterial PaO(2) less than 60 mm Hg. Pulse oximetry significantly overestimates arterial oxygenation, and the inaccuracy is not influenced by liver disease. Nevertheless, pulse oximetry can be a useful screening tool to detect arterial hypoxemia in patients with cirrhosis, but a higher threshold for obtaining an ABG must be used.

Prevalence of hepatopulmonary syndrome in cirrhosis and extrahepatic portal venous obstruction

OBJECTIVE

Hepatopulmonary syndrome (HPS) is characterized by arterial hypoxemia in patients with chronic liver disease caused by abnormal intrapulmonary vasodilations. Data on its frequency vary from 5% to 29%. Most of these studies are from the West and in patients with cirrhosis. We, therefore, studied the prevalence of HPS in patients with liver cirrhosis and extrahepatic portal venous obstruction (EHPVO).

METHODS

We studied 54 consecutive patients with liver cirrhosis (42 men and 12 women; mean age = 44.2 +/- 13 yr; Child grade A: 13, B: 22, and C: 19) and 50 patients with EHPVO (31 men and 19 women; mean age = 23.3 +/- 7.8 yr) Diagnosis of cirrhosis was made by history, liver function abnormalities, endoscopy, and sonography, whereas EHPVO was diagnosed by demonstration of a block in the splenoportovenous axis on sonography. Each of the patients underwent chest x-ray, arterial blood gas analysis, contrast-enhanced echocardiography (CEE), and pulmonary function tests. HPS was diagnosed in a patient with positive CEE, in the presence of hypoxia (PaO2 < 70 mm Hg) and/or elevated alveolar arterial oxygen gradient of > 20 mm Hg in the absence of any underlying cardiopulmonary disease.

RESULTS

Ten of 54 patients (18.5%) with cirrhosis were positive on CEE compared with two of 50 patients (4%) with EHPVO. Six of the 10 patients positive with cirrhosis for CEE had associated hypoxia, whereas only one EHPVO patient with positive CEE had an elevated pulmonary alveolar arterial oxygen gradient of > 20 mm Hg. Thus, the incidence of HPS was 11.1% in patients with cirrhosis, compared with 2% in patients with EHPVO. One patient with HPS and cirrhosis had clinical cyanosis.

CONCLUSION

HPS occurs more commonly in patients with cirrhosis but can also be seen in patients with EHPVO.

Role of nitric oxide in hepatopulmonary syndrome in cirrhotic rats

The hepatopulmonary syndrome (HPS) is characterized by intrapulmonary vascular dilatations and an increased alveolar-arterial oxygen difference (AaPO(2)). Exhaled nitric oxide (NO) concentrations are elevated, suggesting that pulmonary NO overproduction may be the mechanism underlying HPS. We investigated whether common bile duct ligation in rats results in lung NO overproduction and whether normalization of NO synthesis by a 6-wk course of N(G)-nitro-L-arginine methyl ester (L-NAME) (5 mg x kg(-)(1) x d(-)(1)) prevents HPS. Untreated cirrhotic rats showed increases in AaPO(2) and in cerebral uptake of intravenous (99m)Tc-labeled albumin macroaggregates (indicating intrapulmonary vascular dilatations), with decreases in pulmonary vascular resistance and in pulmonary vasoconstriction induced by angiotensin II and hypoxia. Increases were found in exhaled NO; pulmonary total and calcium-dependent NO synthase (NOS) activities; and pulmonary expression of inducible and, to a lesser extent, endothelial NOS. Accumulation of intravascular macrophages accounted for the inducible NOS expression. L-NAME normalized AaPO(2), brain radioactivity, pulmonary vascular resistance, reactivity to hypoxia and angiotensin II, exhaled NO, and NOS activities. These findings suggest that HPS and the associated reduced response to pulmonary vasoconstrictors seen in untreated cirrhotic rats are related to increased pulmonary NO production dependent primarily on increases in the expression and activities of inducible NOS within pulmonary intravascular macrophages.

Hepatopulmonary syndrome associated with autoimmune liver cirrhosis

A 46-year-old woman presented for evaluation of liver dysfunction and dyspnoea. Laboratory examination showed high levels of gamma-globulin, immunoglobulin (Ig)G, and antinuclear antibodies. Laparoscopy demonstrated hepatic cirrhosis. Despite normal spirometry, hypoxaemia (which was worse in standing position) and a low diffusing capacity were present. The shunt ratio calculated using arterial blood gas was 6.4%, but was 40% when measured using 99mTc-macroaggregated albumin scanning. The discrepancy between the ratios indicated that hypoxaemia was caused by intrapulmonary vascular dilatation. The patient was diagnosed with hepatopulmonary syndrome associated with autoimmune liver cirrhosis.

Novel presentation and approach to management of hepatopulmonary syndrome with use of antimicrobial agents

A 44-year-old man with hepatitis C-associated liver cirrhosis, cyanosis, digital clubbing, and platypnea presented with left-side hemiplegia found to be due to a brain abscess. Hepatopulmonary syndrome was diagnosed after demonstration of the presence of a massive intrapulmonary shunt. Although the anomalous vascular channel never was defined anatomically, follow-up studies confirmed the presence of a functional shunt. Culture of a sample from the abscess yielded Streptococcus intermedius. It was hypothesized that the patient's pulmonary vascular pathology was due, in large part, to chronic elevated levels of nitric oxide (a potent vasodilator thought to be generated by endotoxin absorbed from the gut). Treatment with oral norfloxacin was initiated on the basis of data that this antibiotic reduces endotoxemia and concomitant nitric oxide production in patients with cirrhosis. Four months after initiation of treatment, the patient's hypoxia had resolved.

Hepatopulmonary syndrome in candidates for liver transplantation

BACKGROUND

Hepatopulmonary syndrome (HPS) has been defined as a clinical triad, including chronic liver disease, gas exchange defects (increased alveolar-arterial PO2 difference irrespective of the presence of arterial hypoxemia), and widespread intrapulmonary vascular dilatations. We determined the incidence and the clinical and pulmonary functional characteristics of HPS in candidates for orthotopic liver transplantation (OLT) and tested their predicted accuracy.

METHODS

We studied 80 patients with cirrhosis prospectively, and carried out contrast-enhanced (CE) echocardiography and lung function tests, including ventilation-perfusion (V(A)/Q) distributions.

RESULTS

Fourteen patients had HPS (incidence, 17.5%). Patients with HPS (49 +/- 12 (+/-SD) years) had more cutaneous spiders, finger clubbing and dyspnea (P < 0.05 each) and a lower diffusing capacity (DLCO, 56 +/- 18% predicted; P < 0.001) than non-HPS patients (n = 66). Mild to moderate V(A)/Q inequalities and increased intrapulmonary shunt were predominant in HPS patients, but oxygen diffusion impairment was observed in those with hypoxemia (n = 8) only. The DLCO showed a considerable area under the receiver operating characteristic curve (0.89).

CONCLUSIONS

HPS in cirrhotic patient candidates for OLT shows a high incidence and these patients present with distinctive clinical and functional features compared with non-HPS individuals. The presence of a low DLCO may be of help for the diagnosis of HPS.

Transient hepatopulmonary syndrome in a patient with acute hepatitis A

The hepatopulmonary syndrome is defined as the triad of liver disease, hypoxaemia and intrapulmonary vascular dilatation. This syndrome has been described in patients with liver cirrhosis, noncirrhotic portal hypertension, and fulminant hepatic failure, however, there are no previous descriptions of hepatopulmonary syndrome in patients with acute nonfulminant viral hepatitis. We report a 47-year-old, previously healthy man that presented with acute hepatitis A, and developed progressive dyspnoea, platypnoea and orthodeoxia with no evidence of parenchymal or thromboembolic lung disease. PaO2 on room air was 58 mmHg, O2 saturation was 88% and alveolar-arterial O2 gradient was 62%. During his hospitalization serum albumin level decreased to 3.1 g/dl and prothrombin time was prolonged to 16.8 s, however, he remained alert with no signs of hepatic encephalopathy. Contrast echocardiography revealed left heart chamber opacification 3-4 cardiac cycles after the opacification of the right heart chamber, consistent with hepatopulmonary syndrome. During the following days there was a gradual improvement in the patient's condition, with resolution of his dyspnoea and gradual increase of PaO2. Repeat contrast echocardiography and PaO2 determinations, 3 weeks later, were normal. On long-term follow-up the patient remained asymptomatic with normal liver function tests and normal O2 saturation. This report indicates that hepatopulmonary syndrome may be a transient manifestation of acute hepatitis A in the absence of fulminant liver failure.

The hepatopulmonary syndrome

The hepatopulmonary syndrome is a triad of liver disease, increased alveolar-arterial oxygen gradient and intrapulmonary vascular dilatations. Manifestations include orthodeoxia, platypnoea and hyperdynamic circulation. Intrapulmonary vascular abnormalities, perhaps mediated by nitric oxide, cause hypoxaemia by shunting, a perfusion-diffusion defect, and ventilation-perfusion mismatching. Contrast-enhanced echocardiography is the method of choice for demonstrating pulmonary vascular abnormalities, although perfusion lung scanning is a more specific and sensitive test. Angiography is best reserved for patients with poor response to 100% oxygen and defines whether vascular dilatations are of the diffuse 'spongy' type or, less commonly, discrete arteriovenous communications amenable to embolization. About 80% of patients with the hepatopulmonary syndrome eventually have improved oxygenation after liver transplantation, thereby making worsening hypoxaemia the primary indication for transplantation in many instances. Nevertheless, severe hypoxaemia carries a peri-operative mortality of 30% and reliable predictors of successful outcome after transplantation remain to be determined.

Rehabilitating patients with hepatopulmonary syndrome using living-related orthotopic liver transplant: a case report

The objective of this study was to rehabilitate a patient with hepatopulmonary syndrome (HPS) who underwent living-related orthotopic liver transplantation (LT). HPS is rare; it presents severe complication in patients with liver disease. A 17-year-old woman with HPS developed portal hypertension after undergoing Kasai's surgery for congenital biliary atresia and underwent a living-related orthotopic LT. After LT, her allograft functioned well, but she continued to have hypoxemia and orthodeoxia. She was referred for rehabilitation for disuse atrophy, contracture of hip and shoulder joints, left common peroneal nerve palsy, and rehabilitation for respiratory dysfunction. By day 106 after LT, her orthodeoxia and disuse atrophy had improved because of daily exercise training and active joint range of motion exercises. Patients with HPS have orthodeoxia and poor responsiveness to oxygen therapy, and correction of hypoxemia after LT may be delayed. Therefore, rehabilitation approaches for patients with HPS should be based on the pathophysiology and characteristics of HPS.

Hyperdynamic circulation in portal hypertension: a comparative model of arterio-venous fistula

Complications of portal hypertension remain perplexing physiologic phenomena in the understanding of shunt hemodynamics with multiple theories. Hyperdynamic circulation was also found in sepsis, chronic anemia and arterio-venous (A-V) fistula which relate to an increase in nitric oxide. We hypothesize that portosystemic collaterals may mimic an A-V fistula in which the high-pressure portal blood connects with the lower pressure systemic venous circulation. Although these collaterals decompress the portal circulation, a number of secondary hemodynamic phenomena occur which increase portal blood flow and tend to counteract the portal hypotensive effect of the portosystemic shunt. The consequent increases in cardiac output and portal blood flow perfuse the compromised liver. As portal blood flow increases, collateral flow increases and is nearly totally shunted in the systemic circulation. This shunt may eventually introduce a vicious cycle of hyperdynamic circulation into a compromised host. Ultimately, high-output cardiac failure occurs, leading to cirrhotic cardiomyopathy.

Heart diseases affecting the liver and liver diseases affecting the heart

BACKGROUND

The association of cardiac and liver disorders has not been extensively outlined in the literature.

METHODS

A survey of the MEDLINE database was performed to assess the current status of research regarding the association between cardiac and liver disorders.

RESULTS

Combined cardiac and hepatic disorders occur in 3 different settings: heart diseases affecting the liver, liver diseases affecting the heart, and cardiac and hepatic disorders with joint etiology. The spectrum of heart diseases affecting the liver includes mild alterations of liver function tests in heart failure, cardiogenic ischemic hepatitis, congestive liver fibrosis, and cardiac cirrhosis. The liver diseases affecting the heart include complications of cirrhosis such as hepatopulmonary syndrome, portopulmonary hypertension, pericardial effusion, and cirrhotic cardiomyopathy as well as noncirrhotic cardiac disorders such as high-output failure caused by intrahepatic arteriovenous fistulae. Cardiac and hepatic disorders with joint etiology include infectious, metabolic, immune, vasculitic, and toxic disorders. We propose a practical approach to a diagnostic workup of combined cardiac and hepatic disorders based on recognizing the sequence of appearance of the cardiac and liver disease, presence of features of a multisystem disease, and presence of pathognomonic features. The evaluation of combined cardiac and hepatic disorders takes into consideration the expected benefit of treatment and the risks related to invasive procedures. Accordingly, investigations can be limited to ancillary tests for patients with congested liver and mild alterations of liver function tests, in cardiogenic ischemic hepatitis, patients with cardiac cirrhosis who are proposed for conservative treatment, and multisystem disease involving the heart and the liver. Conversely, comprehensive investigations are recommended when invasive therapeutic interventions are considered for the treatment of hepatopulmonary syndrome, portopulmonary hypertension, or arteriovenous fistulae.

CONCLUSION

Classification of a patient to any of the 3 categories-heart diseases affecting the liver, liver diseases affecting the heart, and cardiac and hepatic disorders with joint etiology-permits the physician to narrow the span of the possible diagnoses and allows for a more simple workup.

Diseases of the hepatopulmonary axis

Hepatopulmonary syndrome is the most widely recognized of the processes associated with end-stage liver disease. Chronic liver dysfunction is associated with pulmonary manifestations due to alterations in the production or clearance of circulating cytokines and other mediators. Hepatopulmonary syndrome results in hypoxemia due to pulmonary vasodilatation with significant arteriovenous shunting and ventilation-perfusion mismatch. Hepatic hydrothorax may develop in patients with cirrhosis and ascites. Rarely, pulmonary hypertension occurs in the setting of portal hypertension. A second group of disorders may primarily affect the lungs and liver (the hepatopulmonary axis). Among these are the congenital conditions alpha(1)-antitrypsin deficiency and cystic fibrosis. Autoimmune liver disease may be associated with lymphocytic interstitial pneumonitis, fibrosing alveolitis, intrapulmonary granulomas, and bronchiolitis obliterans with organizing pneumonia. Sarcoidosis affects the lung and liver in up to 70% of patients. Medications such as amiodarone can result in a characteristic radiologic appearance of pulmonary and hepatic toxic effects. Knowledge of these associations will assist the radiologist in forming a meaningful differential diagnosis and may influence treatment decisions.

Clinical and haemodynamic aspects of hepatopulmonary syndrome in Indian patients with cirrhosis

BACKGROUND

Hepatopulmonary syndrome consists of the triad of hepatic dysfunction and/or portal hypertension, intrapulmonary vascular dilatation and hypoxaemia, in the absence of detectable primary cardiopulmonary diseases. In the present study, we examined the frequency of hepatopulmonary syndrome among Indian patients with cirrhosis, and studied clinical predictors and pulmonary haemodynamic alterations.

METHODS

Forty-five patients with cirrhosis and no cardiopulmonary diseases were investigated by air-contrast echocardiography. Where patients were positive, arterial blood gas analysis was carried out. Positive contrast echocardiography with PO2 < 70 mmHg confirmed the diagnosis of hepatopulmonary syndrome. Three cases with the syndrome and 24 without were assessed for haemodynamic status by hepatic and pulmonary catheterization.

RESULTS

Four of 45 cases of cirrhosis (8.9%) had positive contrast echocardiographies, including three (6.7%) with hepatopulmonary syndrome and one 'subclinical' case (positive contrast echocardiography without hypoxaemia). Under haemodynamic study, the mean pulmonary arterial and pulmonary capillary wedge pressures appeared to be lower among those patients with hepatopulmonary syndrome.

CONCLUSIONS

In this small study, the frequency of hepatopulmonary syndrome was relatively low (6.7%). Cyanosis was the only reliable clinical indicator, and there was no clear relationship with the severity of cirrhosis by Child's grading.

Hepatopulmonary syndrome

Hepatopulmonary syndrome is caused by intrapulmonary vasodilation that leads to abnormal arterial gas exchange in the setting of liver disease or portal hypertension. It is seen in up to 15% of cirrhotics and is an increasingly common indication for liver transplantation. Testing for the presence of oxygenation abnormalities and intrapulmonary vasodilation is needed to make the diagnosis. Excess production of nitric oxide in the lung contributes to pulmonary vasodilation and may be triggered by the release of mediators from the damaged liver. No medical therapies are established as effective, and liver transplantation is the only documented curative treatment.

Hepatopulmonary syndrome in inferior vena cava obstruction responding to cavoplasty

Reports show that hepatopulmonary syndrome mostly occurs in the setting of advanced hepatic dysfunction, with the associated vasoactive substance imbalance believed to be responsible for its pathogenesis. However, hepatopulmonary syndrome has also been reported in cases of mild hepatic dysfunction or noncirrhotic portal hypertension, indicating that portal hypertension also plays a part in the pathogenesis. Liver transplantation remains the only therapeutic option of proven benefit. We describe 2 cases of hepatopulmonary syndrome in the setting of inferior vena cava (suprahepatic) obstruction, but with minimal hepatic dysfunction. After balloon cavoplasty, 1 patient showed, in addition to improvement of the features of hepatic outflow obstruction, significant reduction of dyspnea, cyanosis, and hypoxemia with arterial blood gas normalization within 2 weeks and intrapulmonary shunt reversal within 8 weeks. This implies that hemodynamic alterations (such as portal hypertension) independently contribute to the pathogenesis of hepatopulmonary syndrome in at least some of the cases. Therapies aimed at correcting these abnormal hemodynamics may be important in the treatment of this condition, especially when the hepatic functional status by itself does not warrant a liver transplant.

Severe portopulmonary hypertension after liver transplantation in a patient with preexisting hepatopulmonary syndrome

BACKGROUND

Portopulmonary hypertension and hepatopulmonary syndrome have been considered mutually exclusive pulmonary vascular disorders in liver disease states.

METHODS

This current report describes a middle-aged patient, a candidate for liver transplantation, diagnosed with hepatopulmonary syndrome on the basis of clinical, echocardiographic and gas exchange criteria. Unusually high pulmonary pressures were observed at liver transplantation, performed 6 months after the initial diagnosis of hepatopulmonary syndrome. Three months later, the patient developed severe pulmonary hypertension and died of right ventricular failure during a second attempted liver transplantation. Postmortem histologic findings in the lung confirmed the presence of plexogenic pulmonary arteriopathy.

CONCLUSION

This case illustrates the potential occurrence of hepatopulmonary syndrome and portopulmonary hypertension in the same patient, suggesting that the presence of hepatopulmonary syndrome may not preclude the development of portopulmonary hypertension.

Diagnosis and grading of intrapulmonary vascular dilatation in cirrhotic patients with contrast transesophageal echocardiography

BACKGROUND/AIMS

The use of transesophageal contrast echocardiography (TOCE) in the diagnosis of intrapulmonary vascular dilatation (IVD) and hepatopulmonary syndrome (HPS) needs to be studied. We tested the specificity of TOCE using traditional criteria and the value of a new method based on TOCE, a grading scale and a selected contrast.

METHODS

1) Several solutions were tested and two were selected: 20% mannitol and 0.9% saline. 2) 71 cirrhotic patients and 20 controls were studied. Left atrium opacification with contrast was classified into 6 degrees by TOCE. Mild and significant IVD were considered in relation to results in controls. Patients were studied with saline and mannitol-TOCE. Results were compared to transthoracic contrast echocardiography (TTCE), to gas exchange abnormalities and to Child class.

RESULTS

The reproducibility of TOCE grading was excellent, (Kappa >0.9). IVD detection using TTCE, mannitol-TOCE and saline-TOCE was 29.5%, 55% (25% mild and 30% significant), and 45% (38% mild and 7% significant), respectively. The best agreement with TTCE (reference method) was obtained with mannitol-TOCE, using significant IVD as the cut point. By this criterion, 18% reached the criteria of HPS using TTCE and 22% using mannitol-TOCE. Patients with IVD by TTCE had non-significant changes in gas exchange determinations. Patients with significant IVD by saline TOCE had lower mean PaO2 levels (67.3+/-14 vs. 79.5+/-11 mm Hg, p<0.05) than patients without IVD. Patients with significant IVD by mannitol TOCE had higher mean AaPO2 (29.3+/-14 vs. 19.7+/-9 mm Hg; p<0.005) and lower mean PaCO2 levels (30.1+/-4.4 vs. 33.4+/-4.8 mm Hg; p<0.05) than patients without IVD. Severity of IVD by TOCE correlated to Child class (r = 0.43; p<0.001).

CONCLUSIONS

The presence of contrast in the left atrium cannot be a criterion of IVD when TOCE is used. Our semi-quantitative scale has proved to be feasible and reproducible, presenting a good agreement with TTCE, and has shown better correlation with gas exchange abnormalities and Child class. Saline TOCE appears to be more specific in the detection of hypoxemic patients with IVD, but mannitol TOCE adds sensitivity.

[Hepatopulmonary syndrome]

ANAMNESIS

We report about a 60-year-old woman with hepatopulmonary syndrome. The patient suffered from progressive dyspnea and liver cirrhosis following viral hepatitis C, acquired through blood transfusion 30 years ago.

EXAMINATION RESULTS

Remarkable were clinical signs of chronic liver disease (cutaneous spider naevi, palmar erythema) and signs of chronic respiratory failure (clubbing) with platypnea. Arterial pO2 was 33 mm Hg under 41 O2/min nasal oxygen supplement and improved to 74 mm Hg under 81 O2/min. Arterial pO2 deteriorated in upright position (orthodeoxia). Contrast enhanced two-dimensional transthoracic echocardiography showed a delayed microbubble opacification in the left heart chambers (without atrial or ventricular septal defect), suggesting pulmonary vascular dilatations. Perfusion scan with macroaggregated albumin labelled with technetium-99m showed uptake over thyroid, kidneys, liver, and spleen suggesting an abnormal passage through the pulmonary vascular bed. The radiological examination with chest radiography and high resolution computer tomography revealed no signs of interstitial lung disease. The pulmonary artery angiography showed neither anatomical shunts nor malformations.

DIAGNOSIS

The final diagnosis was hepatopulmonary syndrome Type 1. TREATMENT/FOLLOW-UP: The patient underwent liver transplantation with following good function of the liver graft. After 6 months the patient presented in a much better general condition, but with persisting severe hypoxemia whereas the spider naevi disappeared completely. One year after the liver transplantation in the perfusion scan the uptake over thyroid, kidneys, liver, and spleen was absent. The orthodeoxia and hypoxemia improved evidently. From that we conclude that the pulmonary vascular dilatations diminished after liver transplantation.

Pulmonary hypertension following hepatopulmonary syndrome in a patient with cirrhosis

We report the case of a patient with liver cirrhosis who successively developed hepatopulmonary syndrome and portopulmonary hypertension. Initially, the patient presented with severe dyspnea and hypoxemia at rest. Technetium-99 macroaggregated albumin lung perfusion scan demonstrated right-to-left shunt, and hemodynamic study revealed a hyperdynamic state with low pulmonary vascular resistance, thus confirming the diagnosis of hepatopulmonary syndrome. More than 2 years after the onset of pulmonary symptoms, a marked improvement in dyspnea and gas exchange was observed. Lung perfusion scan did not disclose any right-to-left shunt and right-sided heart catheterization showed evidence of severe pulmonary hypertension. We conclude that hepatopulmonary syndrome and portopulmonary hypertension are not mutually exclusive. We hypothesize that, by reversing the phenomenon of intrapulmonary vasodilatation, the development of portopulmonary hypertension interfered with each of the potential causes of hypoxemia in hepatopulmonary syndrome (ventilation-perfusion inequalities, intrapulmonary shunting, oxygen diffusion limitation) and, as a result, led to a correction of hypoxemia.

Diagnosis of hepatopulmonary syndrome with contrast transesophageal echocardiography: advantages over contrast transthoracic echocardiography

The aim of this study was to study the prevalence of hepatopulmonary syndrome (HPS) in cirrhotic patients, comparing the results obtained using contrast transthoracic echocardiography (CTTE) and contrast transesophageal echocardiography (CTEE) in the demonstration and grading of pulmonary vasodilatation (PV). We also analyzed the correlation between gas-exchange abnormalities and PV when it was demonstrated with both techniques. The prevalence of PV and HPS with CTEE in the 88 cirrhotic patients was 28% and 22%, respectively, and with CTEE, 42% (P < 0.05) (middle PV: 35% and significant PV: 7%) and 30% (P < 0.05), respectively. Fifty-six percent of patients diagnosed with PV and with CTTE presented with hypoxemia as did 49% using CTEE (83% of patients with significant PV had hypoxaemia). PaCO2 and diffusing capacity of CO were significantly more decreased in patients with PV than in patients without PV when CTEE was employed. We conclude that CTEE is superior to CTTE in the diagnosis and grading of PV in the diagnosis of HPS in cirrhotic patients, being more sensitive and presenting a better correlation with gas-exchange abnormalities. Given its high sensitivity, CTEE should be carried out in all patients with suspicion of HPS and normal or uncertain CTTE.

Diagnosis of hepatopulmonary syndrome with contrast transesophageal echocardiography: advantages over contrast transthoracic echocardiography

The aim of this study was to study the prevalence of hepatopulmonary syndrome (HPS) in cirrhotic patients, comparing the results obtained using contrast transthoracic echocardiography (CTTE) and contrast transesophageal echocardiography (CTEE) in the demonstration and grading of pulmonary vasodilatation (PV). We also analyzed the correlation between gas-exchange abnormalities and PV when it was demonstrated with both techniques. The prevalence of PV and HPS with CTEE in the 88 cirrhotic patients was 28% and 22%, respectively, and with CTEE, 42% (P < 0.05) (middle PV: 35% and significant PV: 7%) and 30% (P < 0.05), respectively. Fifty-six percent of patients diagnosed with PV and with CTTE presented with hypoxemia as did 49% using CTEE (83% of patients with significant PV had hypoxaemia). PaCO2 and diffusing capacity of CO were significantly more decreased in patients with PV than in patients without PV when CTEE was employed. We conclude that CTEE is superior to CTTE in the diagnosis and grading of PV in the diagnosis of HPS in cirrhotic patients, being more sensitive and presenting a better correlation with gas-exchange abnormalities. Given its high sensitivity, CTEE should be carried out in all patients with suspicion of HPS and normal or uncertain CTTE.

Hepatopulmonary syndrome associated with cardiorespiratory disease

BACKGROUND/AIMS

Hepatopulmonary syndrome is defined as a clinical triad including chronic liver disease, abnormal pulmonary gas exchange resulting ultimately in profound arterial hypoxaemia, and evidence of intrapulmonary vascular dilatations. We report five patients with liver cirrhosis diagnosed with hepatopulmonary syndrome who had associated chronic obstructive or restrictive respiratory diseases.

METHODS

Clinical, radiographic and constrast-enhanced echocardiographic findings, and systemic and pulmonary haemodynamic and gas exchange, including ventilation-perfusion distributions, measurements were assessed in all five patients.

RESULTS

Echocardiography was consistent with the presence of intrapulmonary vasodilation without intracardiac abnormalities, and high resolution computed tomographic scan features were compatible with clinical (3 cases) or histopathological diagnoses (2 cases) of associated respiratory disorders. The most common prominent functional findings were moderate to severe arterial hypoxaemia, caused by moderately to severely increased intrapulmonary shunting and/or mild to moderate low ventilation-perfusion areas, and hypocarbia along with an increased cardiac output and a low pulmonary artery pressure and vascular resistance.

CONCLUSIONS

These functional characteristics, classically reported in the setting of clinically stable, uncomplicated hepatopulmonary syndrome, conform to a distinctively unique, chronic gas exchange pattern. Equally important, these pulmonary haemodynamic-gas exchange hallmarks are not influenced by the co-existence of chronic cardiorespiratory disease states. These data may have clinical relevance for elective indication of hepatic transplantation in patients with life-threatening hepatopulmonary syndrome.

The hepatopulmonary syndrome

The hepatopulmonary syndrome is a disease entity seen in association with liver failure and other disease entities. It is a devastating consequence of liver failure that results in a significant morbidity for affected patients. Currently, there are no identified medications that ameliorate the symptoms of hypoxemia in this disease state. Recent research, however, has begun to unravel the pathobiology of the vascular dilations that arise in the lungs of patients with liver failure. In this article, a compendium of current knowledge is presented, as well as the contemporary methods for identifying and treating patients.

Treatment of hepatopulmonary syndrome with Allium sativum L. (garlic): a pilot trial

No medical therapy exists for subjects with hepatopulmonary syndrome (HPS). A patient with HPS was reported to have improvement in arterial oxygenation while self-administering garlic. Our goal was to determine whether a standardized garlic powder improves arterial oxygenation and dyspnea in subjects with HPS. A prospective, open label uncontrolled pilot study in 15 subjects with HPS were administered garlic powder capsules daily for a minimum of 6 months. Arterial blood gases were determined every 4-8 weeks, in the same position on room air, and a subjective dyspnea transition index was reported. Six of 15 subjects (40%, confidence interval: 0.15-65) had at least a 10 mmHg increase in the P(O2) or decrease in the alveolar-arterial gradient. The mean pre- and postarterial difference in these patients were: P(O2) (14+/-4 mmHg) and alveolar-arterial gradient (18+/-5 mmHg). All 6 subjects who responded to garlic had less dyspnea on exertion. Garlic improved arterial oxygenation in younger subjects (mean 40 versus 56 years old; p = 0.021) or those with lower macroaggregated albumin shunt fractions (mean 21 versus 44%, p = 0.058). Garlic may improve arterial oxygenation and symptoms in patients with hepatopulmonary syndrome and warrants further investigation.

Response to symptom-limited exercise in patients with the hepatopulmonary syndrome

OBJECTIVE

To study the response to symptom-limited exercise in patients with the hepatopulmonary syndrome (HPS).

DESIGN

The response to maximal cardiopulmonary exercise (CPX) was studied in 5 patients with HPS and compared with 10 case control (normoxemic, NC) cirrhotics (matched for age, gender, etiology and severity of liver disease, tobacco use, and beta-blocker therapy) and 9 hypoxemic control cirrhotics (HC) without clinical evidence of HPS.

SETTING

Cardiopulmonary exercise physiology laboratory in a tertiary care referral center.

PATIENTS

Cirrhotics referred for CPX as part of their preliver transplantation evaluation.

MEASUREMENTS

Standard pulmonary function tests and echocardiography were performed to assess resting pulmonary and cardiac function. Peak oxygen consumption (VO2), minute ventilation, arterial blood gases, and dead space (VD/VT) were determined during symptom-limited maximal CPX.

RESULTS

Resting spirometry and lung volumes were similar between HPS and NC subjects, while HC subjects had restrictive physiology. Differences existed in diffusing capacity corrected for hemoglobin and alveolar volume percent predicted (HPS, 45+/-2 vs NC, 68+/-3, p<0.05; vs HC, 70+/-4, p<0.05), PaO2 (HPS, 70+/-5 mm Hg; HC, 79+/-3 mm Hg, vs NC, 102+/-3 mm Hg, p<0.05) and alveolar-arterial (A-a) O2 gradient (HPS, 42+/-8 mm Hg vs HC, 27+/-2 mm Hg, p<0.05; vs NC, 6+/-2 mm Hg, p<0.05). During CPX, HPS patients achieved a lower peak VO2 percent predicted (HPS, 55+/-6 vs NC, 73+/-3, p<0.05; vs HC, 71+/-5, p<0.05) and VO2 at the ventilatory threshold as percent predicted peak VO2 (HPS, 36+/-2 vs NC, 55+/-4, p<0.05; vs HC 55+/-5, p<0.05). While no differences existed in heart rate and breathing reserve, HPS patients had significantly lower PaO2 (HPS, 50+/-5 mm Hg vs NC, 97+/-4 mm Hg, p<0.05; vs HC, 87+/-6 mm Hg, p<0.05), wider A-a O2 gradient (HPS, 73+/-5 mm Hg vs NC, 13+/-3 mm Hg, p<0.05; vs HC, 31+/-5 mm Hg, p<0.05) and higher VD/VT (HPS, 0.36+/-.03 vs NC, 0.18+/-.02, p<0.05; vs HC, 0.28+/-.02, p<0.05) at peak exercise. For HPS patients, VO2 was negatively correlated with VD/VT (r2=0.9) and positively correlated with PaO2 (r2=0.41) at peak exercise.

CONCLUSIONS

Patients with HPS demonstrate a severe reduction in aerobic capacity, beyond that found in cirrhotics without syndrome. The significant hypoxemia and elevated VD/VT at peak exercise suggest that an abnormal pulmonary circulation contributes to further exercise limitation in patients with HPS.

Diagnosis of hepatopulmonary syndrome with contrast transthoracic echocardiography and histological confirmation

We report a patient with cirrhosis and hepatopulmonary syndrome. This syndrome is an entity characterized by anomalies in the arterial oxygenation in patients with chronic hepatic disease and/or portal hypertension and demonstration of pulmonary vasodilatation (PV) in absence of primary cardiac or pulmonary disease. We show that the finding of PV with transthoracic contrast enhanced echocardiography (TCEE) in the diagnosis of PV is real and corresponds to direct measurement of capillary diameter by morphometry.

Arterial hypoxaemia in cirrhosis: fact or fiction?

BACKGROUND

Although low arterial oxygen tension (Po2) has been claimed to occur in one to two thirds of patients with cirrhosis, hypoxaemia appears to be rare in clinical practice.

AIMS

To assess the frequency of arterial hypoxaemia in cirrhosis in relation to clinical and haemodynamic characteristics.

PATIENTS

One hundred and forty two patients with cirrhosis without significant hepatic encephalopathy (grades 0-I) (41 patients in Child class A, 57 in class B, and 44 in class C) and 21 patients with hepatic encephalopathy.

RESULTS

Mean Po2 in kPa was 11.3 in Child class A, 10.8 in class B, 10.6 in class C, and 10.6 in patients with encephalopathy (p < 0.05). The fraction of patients with Po2 below the lower normal limit of 9.6 kPa was 10%, 28%, 25%, and 43%, respectively in class A, B, C, and in patients with encephalopathy (p < 0.05). Oxygen saturation (So2) in these groups was respectively: 96%, 96%, 96%, and 93% (NS). So2 was below the lower limit of 92% in 0%, 9%, 7%, and 24% (p < 0.05). In patients without hepatic encephalopathy, a multivariate regression analysis revealed that independent determinants of a low Po2 were a high arterial carbon dioxide tension, a low systemic vascular resistance, and a low indocyanine green clearance (p < 0.0001).

CONCLUSION

The prevalence of arterial hypoxaemia in cirrhosis is about 22% in patients without encephalopathy, but it varies from 10-40% depending on the degree of hepatic dysfunction. Arterial hypoxaemia in patients with cirrhosis of differing severity seems lower than previously reported, and patients with severe arterial hypoxaemia are rare.

Use of macroaggregated albumin lung perfusion scan to diagnose hepatopulmonary syndrome: a new approach

BACKGROUND & AIMS

We have reported that contrast echocardiography is a sensitive screening test for the hepatopulmonary syndrome (HPS). However, contrast echocardiography lacks specificity because many cirrhotic patients have positive study results with normal arterial blood gases and therefore do not fulfill criteria for HPS. The aim of this study was to assess the role of macroaggregated albumin lung perfusion scans (MAA scans) in the diagnosis of HPS.

METHODS

MAA scans were performed in 25 patients with HPS, 25 cirrhotic patients without HPS, and 15 hypoxemic subjects with intrinsic lung disease alone. An MAA shunt fraction was calculated from brain and lung counts.

RESULTS

MAA scan results were positive in 21 of 25 patients with HPS and negative in all controls. All 21 patients with positive MAA scans had PO2 values of <60 mm Hg. There was a strong inverse correlation between the degree of the MAA shunt fraction and arterial hypoxemia (r = -0.726).

CONCLUSIONS

A positive MAA scan result in cirrhosis is specific for the presence of moderate to severe HPS. We speculate that MAA scans may be particularly useful in evaluating the contribution of HPS to the hypoxemia in cirrhotic patients with intrinsic lung disease.

Adverse effects of amiodarone

Amiodarone was introduced 30 years ago as an antianginal agent and subsequently has been used as an antiarrhythmic agent. This drug was initially used for patients with malignant ventricular arrhythmias; however, currently it is being used broadly for rate and rhythm control in patients with atrial fibrillation. At first, amiodarone was primarily used by cardiologists and today it is used throughout the medical profession. Amiodarone therapy can potentially result in a wide range of adverse effects. The majority of these adverse effects are dose related and reversible. The following is a review of the adverse effects and drug interactions of amiodarone along with recommendations for identification and management of these adverse effects.

Hepatopulmonary syndrome: the paradigm of liver-induced hypoxaemia

The current chapter deals with the concept, clinical manifestations and diagnostic tools of the hepatopulmonary syndrome (HPS) and highlights its most salient pathophysiological, mechanistic and therapeutic aspects. Defined as a clinical triad, including a chronic liver disorder, pulmonary gas exchange abnormalities and generalized pulmonary vascular dilatations, in the absence of intrinsic cardiopulmonary disease, this entity is currently growing in interest with both clinicians and surgeons. The combination of arterial hypoxaemia, high cardiac output with normal or low pulmonary artery pressure, and finger clubbing in a patient with advanced liver disease should strongly suggest the diagnosis of HPS. Its potential high prevalence together with failure of numerous therapeutic approaches depicts a life-threatening unique clinical condition that may dramatically benefit with an elective indication of liver transplantation (LT). A better orchestration of the concepts of the pathophysiology of this lung-liver interplay may foster our knowledge and improve the clinical management and indications of LT.

The hepatopulmonary syndrome

The hepatopulmonary syndrome occurs in subjects with chronic liver disease and/or portal hypertension who develop intrapulmonary vasodilation resulting in arterial deoxygenation. Clinical and basic science studies investigating the pathophysiology of HPS are presented. A diagnostic algorithm is provided using contrast echocardiography, the lung perfusion scan, and pulmonary angiography. Medical therapy and experience with liver transplantation are reviewed.

Hepatopulmonary syndrome with progressive hypoxemia as an indication for liver transplantation: case reports and literature review

In the hepatopulmonary syndrome (HPS), a pulmonary vascular complication of liver disease, severe hypoxemia due to pulmonary vascular dilatation can be extremely debilitating. Determining whether patients with advanced liver disease and HPS should be considered for liver transplantation is difficult. We describe three patients with progressive and severe hypoxemia who underwent successful liver transplantation and had resolution of their arterial hypoxemia. In these patients, the progressive pulmonary deterioration accelerated the need and was considered an indication for liver transplantation rather than being considered an absolute or relative contraindication. In addition, we review the literature on 81 pediatric and adult patients with HPS who underwent liver transplantation and specifically highlight mortality, morbidity, syndrome resolution, and prognostic factors. Posttransplantation mortality (16%) was associated with the severity of hypoxemia (mean arterial oxygen tension [PaO2] in 68 survivors was 54.2 +/- 13.2 mm Hg and in 13 nonsurvivors was 44.7 +/- 7.7 mm Hg; P<0.03). Patients with a pretransplantation PaO2 of 50 mm Hg or lower had significantly more frequent mortality (30%) in comparison with those with a PaO2 greater than 50 mm Hg (4%; P<0.02). Pulmonary recommendations that address the severity of hypoxemia and candidacy for liver transplantation are discussed.

Platelet basal cytosolic calcium: the influence of plasma factors in cirrhosis

BACKGROUND

Platelet cytosolic calcium is necessary for normal platelet function, and may reflect intracellular signalling in vascular smooth muscle cells.

METHODS

The cytosolic calcium of platelets from patients with cirrhosis and control subjects was measured in contact with plasma from either source, using FURA 2AM.

RESULTS

The basal cytosolic calcium of patients with cirrhosis was found to be significantly lower than that of control subjects (95.7 +/- 10.0 cf. 128.0 +/- 7.8 nmol/l; p = 0.02). When platelets from control subjects were incubated for 45 min with freshly obtained plasma from patients with cirrhosis, the control platelet cytosolic calcium fell to concentrations similar to those of patient platelets (93.0 +/- 7.8 nmol/l; p < 0.005). Such an effect was not observed if patient serum or plasma that had previously been frozen was used. When patient platelets were incubated with fresh control subject plasma, the platelet cytosolic calcium increased (165.4 +/- 19.9 nmol/l; p = 0.01).

CONCLUSION

These results indicate that a plasma-borne factor, sensitive to freezing, is responsible for the abnormalities of platelet calcium signalling noted in cirrhosis.

Effect of oxygen inhalation on systemic, central, and splanchnic haemodynamics in cirrhosis

BACKGROUND/AIMS

Patients with cirrhosis exhibit a hyperdynamic circulation with increased cardiac output and low arterial blood pressure. The aim of the present study was to assess the effects of oxygen inhalation on systemic, central, and splanchnic haemodynamics and vasoactive systems in patients with cirrhosis (n = 19).

RESULTS

Spirometry was normal, but the carbon monoxide diffusing capacity (transfer factor) was significantly decreased, 18.8 ml.min-1.mmHg-1 (-32% of that predicted, p < 0.0001), and correlated significantly with the cardiac output (r = 0.78, p < 0.0005), plasma volume (r = 0.72, p < 0.001) and the central and arterial blood volume (r = 0.67, p < 0.005). After inhalation of 100% oxygen over a period of 20 min, the cardiac output decreased from 7.4 to 6.6 l/min (p < 0.0005), and the systemic vascular resistance increased from 980 to 1124 dyn.s.cm-5 (p < 0.005). The change in systemic vascular resistance was significantly greater in patients with mild liver dysfunction than in those with severe liver dysfunction (p < 0.02). In contrast, no significant changes were seen in the arterial or portal venous pressures during inhalation of oxygen. Arterial concentrations of catecholamines, renin, endothelin-1, and calcitonin gene-related peptide were all increased in patients with cirrhosis, but only the catecholamine concentrations decreased significantly (noradrenaline -13%, p < 0.02 and adrenaline -16%, p < 0.01) in response to oxygen.

CONCLUSION

During oxygen inhalation cardiac output decreases and systemic vascular resistance increases in association with a decrease in arterial concentrations of catecholamine, but oxygen supply in patients with cirrhosis does not normalise the hyperdynamic circulation or the low arterial blood pressure.

Hepatopulmonary syndrome. A pulmonary vascular complication of liver disease

Hepatopulmonary syndrome is part of the spectrum of pulmonary vascular disorders seen in advanced liver disease. The pathophysiology of these entities likely is dependent on the degree of pulmonary vasoconstriction or vasodilation that occurs. Our understanding of hepatopulmonary syndrome has helped further our knowledge of the interaction of the liver and the lung. Advances in the management of this disorder, especially liver transplantation, finally have allowed us to offer some hope to patients with this disease.

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

The hepatopulmonary syndrome results from erythrocytes bypassing the lung without oxygenation. In addition to ventilation-perfusion mismatching, the hypoxemia may result from portapulmonary shunting, passage around alveoli through pleural and hilar blood vessels, and intrapulmonary vascular dilatations. Dilated vascular channels between arteries and veins on the pleural surface are seen more often than dilated intrapulmonary capillaries in chronic liver disease. These anastomoses appear grossly as vascular "spider nevi" on the pleura. Portal vein-to-pulmonary vein anastomoses could produce arterial hypoxemia because the deoxygenated portal venous blood can mix with oxygenated pulmonary venous blood. There is an association of esophageal varices with the hepatopulmonary syndrome and anastomoses between the portal veins and pulmonary veins have been found in both animals and humans. As portal pressures increase, the mediastinal veins enlarge, enhancing the chance that they may penetrate the pleura and drain into pulmonary veins. Direct splenic injections in patients, however, suggest that this shunt pathway is uncommon and small. Pulmonary artery injection studies have demonstrated dilated intrapulmonary vascular segments in humans and animals. Dilation of capillaries may allow a more rapid flow through the lung and the greater distance between the erythrocyte and alveolar wall may make it more difficult to oxygenate rapidly passing erythrocytes. Pulmonary capillary dilation can explain the abnormalities of the perfusion lung scan and contrast echocardiogram that portapulmonary shunting cannot. Pulmonary hypertension may occur in chronic liver disease even without arterial hypoxemia, but it is rare. The prevalence of hypertensive pulmonary vascular disease in patients with cirrhosis of the liver is less than 1%, although a higher percentage (2%) has been found when patients with portal hypertension were studied by cardiac catheterization. The hypertensive pulmonary vascular disease (pulmonary arteriopathy with plexiform lesions) that occurs in patients with liver disease appears identical to that encountered in patients with congenital cardiac shunts and unexplained (primary) pulmonary hypertension.

Mechanisms of gas exchange impairment in patients with liver cirrhosis

This article reviews the basic pathophysiologic mechanisms underlying the abnormal pulmonary gas exchange often seen in patients with cirrhosis. To summarize, the following keypoints seem appropriate: (1) Patients with cirrhosis have a low pulmonary vascular tone characterized by a poor or absent hypoxic pressor response. This results in a marked dilation of the pulmonary vasculature. (2) This abnormal pulmonary vascular tone, independently of airway disease, causes VA/Q mismatch and mild to moderate hypoxemia. Yet, as liver disease progresses and hepatocellular function deteriorates, more severe degrees of intrapulmonary shunt emerge and, probably, O2 diffusion limitation ensues, causing severe respiratory failure (see Table 1). (3) At rest, the high cardiac output and minute ventilation of cirrhosis minimize the degree of arterial hypoxemia that otherwise would be expected from the observed degree of both VA/Q inequality and intrapulmonary shunt. During exercise, the relative "normalization' (with respect to metabolic demands) of the hemodynamic and ventilatory status of the patient explains the fall in PaO2. (4) A clear pathogenic mechanism of these pathophysiologic abnormalities is still lacking, although available evidence suggests that both the liver and the endothelial cells may play a pivotal role in the regulation of the pulmonary vascular tone in these patients. (5) To date, no pharmacologic intervention has been effective in treating hypoxemia in these patients. Yet liver transplantation helps in most of them. This observation reinforces the functional nature of the gas exchange abnormalities of cirrhosis.

The hepatopulmonary syndrome. Effect of liver transplantation

The role of liver transplantation as a treatment for the hepatopulmonary syndrome (HPS) has had an evolving and controversial history. Although early experience was disappointing, more recent experience has documented resolution of HPS-associated hypoxemia after liver transplantation. This article reviews the history of liver transplantation for patients with the hepatopulmonary syndrome. In addition, we discuss the clinical features that have been considered to predict successful reversibility and the time frame over which reversal occurs. Despite this evolution of thought, many basic questions still remain.

Diagnostic utility of contrast echocardiography and lung perfusion scan in patients with hepatopulmonary syndrome

BACKGROUND & AIMS

Two modalities, contrast echocardiography and lung perfusion scan, are used to identify intrapulmonary vascular dilatation and diagnose hepatopulmonary syndrome (HPS), but a comparison of these two procedures has not been performed. The aim of this study was to compare the use of these diagnostic modalities in detecting intrapulmonary vascular dilatation and diagnosing HPS.

METHODS

Forty consecutive outpatients with biopsy-proven cirrhosis had contrast echocardiography, a lung perfusion scan, and arterial blood gases analyzed.

RESULTS

Fifteen of 40 cirrhotics (38%) had positive contrast echocardiogram results. Seven patients with positive echocardiogram results had gas exchange abnormalities and could be considered to have HPS (7 of 40 [17.5%]). Three of these patients were hypoxemic and had no concurrent cardiopulmonary disease, and each had positive contrast echocardiogram and lung perfusion scan results and were readily diagnosed as having HPS. The other 4 patients (3 hypoxemic and 1 normoxemic with an elevated alveolar-arterial gradient) had coexisting intrinsic lung disease and/or chest radiograph abnormalities complicating the diagnosis of HPS, and each had positive echocardiogram and negative lung scan results. The remaining 8 patients with positive echocardiogram results had normal lung scan and normal gas exchange results. No patient had positive lung scan and negative contrast echocardiogram results.

CONCLUSIONS

Contrast echocardiography is the most useful screening test for intrapulmonary vasodilatation and may be positive more frequently than lung perfusion scans in patients with HPS.

Hepatopulmonary syndrome: what are we learning from interventional radiology, liver transplantation, and other disorders?

Interventional radiology (pulmonary angiography, coil embolotherapy, and TIPS) in patients with HPS seems to provide both diagnostic data and therapeutic results of clinical importance. The case report by Riegler et al. is instructive and emphasizes the need for further prospective study to analyze the successes and failures in terms of measurable clinical variable in a procedure such as TIPS. The resolution of hypoxemia following liver transplantation and careful patient selection offers hope to patients with severe, debilitating oxygenation abnormalities caused by HPS.

Transjugular intrahepatic portosystemic shunt improves oxygenation in hepatopulmonary syndrome

Hepatopulmonary syndrome is a complication of chronic liver disease in which arterial hypoxemia results from abnormalities in pulmonary blood flow. Severe hypoxemia can lead to clinical deterioration and death. Although the etiology is unknown, portal hypertension seems to be an important factor in the development of hepatopulmonary syndrome. No effective pharmacological therapy has been identified, but liver transplantation may be curative. Arterial hypoxemia may complicate transplant surgery, however, and resolution of the syndrome after liver transplantation is performed may be delayed. In addition, it seems that complete reversal of oxygenation abnormalities after liver transplantation is performed is unpredictable. We described a patient with hepatopulmonary syndrome who noted improvement in symptoms of dyspnea after the placement of a transjugular intrahepatic portosystemic shunt. Arterial oxygenation and calculated shunt fraction improved significantly during the follow-up period, and liver transplantation was subsequently performed without difficulty. Portal decompression using transjugular intrahepatic portosystemic shunt may represent a palliative therapy for hepatopulmonary syndrome in patients awaiting liver transplantation.

Prevalence and reversibility of the hepatopulmonary syndrome after liver transplantation. The Cleveland Clinic experience

To ascertain the prevalence and reversibility of the hepatopulmonary syndrome, we reviewed the cases of 98 patients undergoing liver transplantation at the Cleveland (Ohio) Clinic Foundation from June 1988 through July 1992 and identified 4 patients with clinically recognized hepatopulmonary syndrome (prevalence 4%). All 4 patients ultimately had complete reversal of their disorder. As reviewed herein, the prevalence of the hepatopulmonary syndrome in the current series is lower than in previous reports, possibly reflecting a dependence on its clinical recognition in this series rather than the use of routine screening tests. This report confirms previous experience that the hepatopulmonary syndrome may be reversible after transplantation.