Pulmonary vascular abnormalities in cirrhosis

Two pulmonary vascular disorders can occur in liver disease and/or portal hypertension: the hepatopulmonary syndrome (HPS), which is characterized by intrapulmonary vascular dilatations, and portopulmonary hypertension (POPH), in which pulmonary vascular resistance is elevated. POPH and HPS are characterized by distinct pulmonary microvascular remodelling, which occurs at different anatomical sites of the pulmonary microcirculation. The exact pathophysiological mechanisms of these pulmonary vascular disorders are unknown. However, as HPS and POPH have been reported in patients with extrahepatic portal hypertension, the factor that determines their development must be portal hypertension. The clinical presentations are very different, with gas exchange impairment in HPS and hemodynamic failure in POPH. The severity of HPS seems to parallel the severity of liver failure, whereas no simple relationship has been identified between hepatic impairment and the severity of POPH. Resolution of HPS is common after liver transplantation, which has an uncertain effect in POPH.

[Pulmonary complication of liver disease]

Hepatopulmonary syndrome (HPS) and portopulmonary hypertension (POPH) are two distinct pulmonary complications of liver disease, which seem pathogenetically linked to the presence of portal hypertension. The most common presenting symptom of both syndromes is dyspnoea, but HPS is more prevalent in 5-30% of patients. The diagnosis of HPS requires the documentation of arterial hypoxemia and intrapulmonary vascular dilatation with anatomical shunting. In contrast, POPH has a prevalence of 2-16% and is only considered proven, if other causes of the pulmonary hypertension than the high portal pressure are excluded. Moderate to severe HPS or POPH carry a poor prognosis and liver transplantation remains the only curative treatment, although POPH in particular is associated with high perioperative mortality.

[Hepatopulmonary syndrome in a patient with adenocarcinoma of the colon metastatic to the liver and no apparent chronic liver disease]

Hepatopulmonary syndrome consists of a clinical triad: arterial blood deoxygenation, intrapulmonary vasodilation, and liver disease. Both acute and chronic cases of this syndrome have been reported, and the most common cause is cirrhosis. The principle disease mechanism is dilation of the pulmonary blood vessels causing alterations in gas exchange. Increased pulmonary production of nitric acid has been implicated as the primary pathogenic mechanism of vasodilation although it has also been associated with imbalance between vasodilators and vasoconstrictors. We describe the case of a patient with hepatopulmonary syndrome and adenocarcinoma of the colon with metastases to a previously healthy liver.

[Risk-classification in liver cirrhosis]

Prognostic models are useful in estimating disease severity and survivial and are used to make decisions regarding specific medical interventions. These models are developed using analytical methods that involve determining the effects of variables of interest (eg, laboratory values) on specific outcomes such as death. There are two models that are used commonly in the care of patients witch chronic liver disease: the Child-Pugh score and the recently described Model for End-Stage Liver Disease (MELD). MELD score is a prospectively developed and validated chronic liver disease severity scoring system that uses a patient's laboratory values for serum bilirubin, serum creatinine, and the international normalized ratio for prothrombin time (INR) to predict survival. The score was proposed as a the most promising alternative to Child-Pugh score. Weather Child-Pugh score should definitely be abandoned for MELD score remains uncertain. The aims of this paper are to summarize and to compare the characteristics, applications and limitations of Child-Pugh and MELD scores.

An unusual cause of dyspnoea complicating right upper abdominal swelling

A middle aged, non-addict male presented with right upper abdominal pain and swelling with respiratory distress. Examination revealed central cyanosis, bipedal pitting edema with prominent epigastric and back veins. Liver was enlarged, tender, spanned 20 cm without any splenomegaly or ascites. Other systems were clinically normal. Laboratory investigations showed polymorphonuclear leucocytosis with slightly deranged liver function. Abdominal ultrasonography showed an abscess in the right lobe of the liver with compressed inferior vena cava (IVC), middle and left hepatic veins. Arterial blood gas (ABG) documented hypoxia with orthodeoxia and air-contrast echocardiography was suggestive of an intrapulmonary shunt. A diagnosis of hepato-pulmonary syndrome (HPS) was made with near normal liver function secondary to amebic liver abscess. It reversed completely following successful treatment of the liver abscess.

[The hepato-pulmonary syndrome--where do we stand in the year 2006?]

The hepato-pulmonary syndrome (HPS) is characterized by a combination of liver disease and pulmonary gas exchange abnormalities with arterial hypoxemia, intrapulmonary vasodilatation and arteriovenous shunting in the absence of intrinsic cardiopulmonary disease. The course of the disease is typically progressive. The mortality rate correlates with the pulmonary shunt volume and the degree of hypoxemia at room air. While the patho-physiology of HPS is still not fully understood, a multifactorial etiology is favored. Apart from functional intrapulmonary arteriovenous shunts which appear to represent a major factor in the development of HPS, both ventilation-perfusion mismatch and limited oxygen diffusion contribute to the HPS. Regarding its clinical appearance, pulmonary and hepatic symptoms have to be distinguished. Contrast echocardiography is the primary diagnostic tool. Symptomatically, hypoxemia can be treated with oxygen. So far, the only successful treatment approach which has been tested in larger patient groups, is liver transplantation. Given this background, the aim of this review is to critically discuss current concepts of this serious complication of liver diseases.

The diagnosis and treatment of hepatopulmonary syndrome

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

Hepatopulmonary syndrome in patients with chronic liver disease: role of pulse oximetry

Background

Hepatopulmonary syndrome (HPS) is a rare complication of liver diseases of different etiologies and may indicate a poor prognosis. Therefore, a simple non-invasive screening method to detect HPS would be highly desirable. In this study pulse oximetry was evaluated to identify patients with HPS.

Methods

In 316 consecutive patients with liver cirrhosis (n = 245), chronic hepatitis (n = 69) or non-cirrhotic portal hypertension (n = 2) arterial oxygen saturation (SaO₂) was determined using a pulse oximeter. In patients with SaO₂ ≤92% in supine position and/or a decrease of ≥4% after change from supine to upright position further diagnostic procedures were performed, including contrast-enhanced echocardiography and perfusion lung scan.

Results

Seventeen patients (5.4%) had a pathological SaO₂. Four patients (1.3%) had HPS. HPS patients had a significant lower mean SaO₂ in supine (89.7%, SD 5.4 vs. 96.0%, SD 2.3; p = 0.003) and upright position (84.3%, SD 5.0 vs. 96.0%, SD 2.4; p = 0.001) and had a lower mean PaO₂ (56.2 mm Hg, SD 15.2 vs. 71.2 mm Hg, SD 20.2; p = 0.02) as compared to patients without HPS. The mean ΔSaO₂ (difference between supine and upright position) was 5.50 (SD 7) in HPS patients compared to non-HPS patients who showed no change (p = 0.001). There was a strong correlation between shunt volume and the SaO₂ values (R = -0.94).

Conclusion

Arterial SaO₂ determination in supine and upright position is a useful non-invasive screening test for HPS and correlates well with the intrapulmonary shunt volume.

Clinical features of hepatopulmonary syndrome in cirrhotic patients

AIM: To evaluate the frequency, clinical and paraclinical features of hepatopulmonary syndrome (HPS) and to determine their predictive values in diagnosis of this syndrome in patients in Iran.

METHODS: Fifty four cirrhotic patients underwent contrast enhanced echocardiography to detect intrapulmonary and intracardiac shunts by two cardiologists. Arterial blood oxygen, O₂ gradient (A-a) and orthodoxy were measured by arterial blood gas (ABG) test. The patients positive for diagnostic criteria of HPS were defined as clinical HPS cases and those manifesting the intrapulmonary arterial dilation but no other criteria (arterial blood hypoxemia) were defined as lHPS cases. HPS frequency, sensitivity, positive and negative predictive values of clinical and paraclinical features were studied.

RESULTS: Ten (18.5%) and seven (13%) cases had clinical and subclinical HPS, respectively. The most common etiology was hepatitis B. Dyspnea (100%) and cyanosis (90%) were the most prevalent clinical features. Dyspnea and clubbing were the most sensitive and specific clinical features respectively. No significant relationship was found between HPS and splenomegaly, ascites, edema, jaundice, oliguria, and collateral veins. HPS was more prevalent in hepatitis B. PaO₂< 70 and arterial-alveolar gradient had the highest sensitivity in HPS patients. Orthodoxy specificity was 100%.

CONCLUSION: Clubbing with positive predictive value (PPV) of 75% and dyspnea with negative predictive value (NPV) of 75% are the best clinical factors in diagnosis of HPS syndrome. PaO₂< 70 and P (A-a) O₂> 30 and their sum, are the most valuable negative and positive predictive values in HPS patients.

The pulmonary involvement in portal hypertension: portopulmonary hypertension and hepatopulmonary syndrome

Pulmonary abnormalities are common in patients with advanced chronic liver disease. Two distinct syndromes strictly related to the presence of portal hypertension, but clearly different from a pathophysiologic point of view, have been identified. Portopulmonary hypertension, characterized by an increased pulmonary arterial pressure, is due to a progressive arteriolar vasoconstriction induced by excess local production of vasoconstrictor substances. Hepatopulmonary syndrome results from intrapulmonary microvascular dilation caused by an inadequate synthesis or metabolism of putative pulmonary vasoactive substances leading to a functional vasodilation of the pulmonary vasculature, ultimately leading to hypoxemia. Controversies on pathogenesis imply different tentative therapeutic approaches for the medical management of these conditions. The development of portopulmonary hypertension or the hepatopulmonary syndrome has important clinical and prognostic implications facing the impact of new therapeutic strategies for the management of the main complications of advanced liver diseases on cardiopulmonary function.

Gas exchange detection of right-to-left shunt in dyspneic patients: Report of three cases

We evaluated three patients with undiagnosed complaints of progressive dyspnea. Based on gas-exchange findings as the initial diagnostic tool, the high ventilatory equivalents for CO2, low sustained end-tidal PCO2, hypoxemia, and central cardiovascular dysfunction during cardiopulmonary exercise testing (CPET) suggested that each had significant pulmonary vasculopathy with right-to-left shunting. The diagnoses of Osler-Rendu-Weber syndrome, ventricular septal defect with Eisenmenger's complex, and hepatopulmonary syndrome were later confirmed by pulmonary angiography, cardiac catheterization, and contrast enhanced echocardiography respectively. We suggest that CPET is an appropriate noninvasive tool to begin and guide the evaluation of undiagnosed dyspnea.

Clinical predictors and characteristics of patients with chronic liver disease and intrapulmonary shunts

BACKGROUND

Intrapulmonary shunting (IPS) is a well-described phenomenon in chronic liver disease but its significance is not known.

HYPOTHESIS

The study was undertaken to enhance our understanding of the characteristics and prevalence of IPS.

METHODS

We retrospectively studied 204 consecutive patients with end-stage chronic liver disease who underwent a dobutamine stress echocardiogram, along with a saline contrast bubble study, as part of their pretransplant evaluation.

RESULTS

Intrapulmonary shunting of any degree was present in 56.4% of patients. Patients with IPS were more likely to report alcohol use and less likely to have diabetes mellitus. Patients in Child-Pugh classification C were more likely to have IPS than those with classification A or B. The resting room air PaO2 levels were significantly lower in patients with grade 3-4 IPS than in those with grade 1-2. Elevated estimated pulmonary systolic pressure on echocardiography was more prevalent in patients with than in those without IPS.

CONCLUSIONS

A majority of patients with end-stage chronic liver disease undergoing transplant evaluation have IPS. There are important baseline differences between patients with and without IPS. The presence of IPS is associated with increased severity of chronic liver disease. Further study is required to define the prognostic significance of IPS and its impact on future liver transplantation.

[Exhaled nitric oxide as a marker of diseases]

Recently a method to measure nitric oxide (NO) concentration in exhaled air has been developed. The method is non-invasive and easy to perform and it provides information on a fascinating molecule, with such extensive respiratory functions, ranging from bronchial and vascular dilation to ciliary motion and antibacterial defense. Nasal and sinus cavities are the site of major NO production, followed by airway and alveolar compartment. A very low nasal NO production is associated with ciliary dyskinesia, a disease characterized by severe chronic sinusitis and bronchiectasis. An increased concentration of NO in exhaled air has been reported in airway diseases, characterized by airway inflammation, such as bronchial asthma, where its concentration is related to bronchial hyperresponsiveness and sputum eosinophilia. Exhaled NO concentration in asthma is a sensitive marker of airway inflammation that reacts rapidly in response to treatment or exacerbation of disease. Clinical application of exhaled NO measurement include monitoring compliance and response to treatment, disease activity, diagnosis of asthma, and the prediction of acute exacerbations. Exhaled NO concentration may be increased also in other diseases, as COPD, bronchiectasis and some connective tissue diseases (SLE and systemic sclerosis). An increased NO production from alveolar source has been shown to be involved in oxygenation impairment of patients with liver disease, particularly in case of hepato-pulmonary syndrome.

A severe (type II) hepatopulmonary syndrome in a patient with idiopathic portal hypertension and treatment with paroxetine

The hepatopulmonary syndrome has been defined as chronic liver disease accompanied by abnormal pulmonary gas exchange, which might result in arterial deoxygenation, and widespread intrapulmonary vasodilation. Although it has been pointed out that hepatopulmonary syndrome occurs in liver cirrhosis, there are a few studies in the literature reporting noncirrhotic portal hypertension as a cause of hepatopulmonary syndrome. Currently, liver transplantation is the only effective therapy for such patients. on the other hand, there is also a proposal about considering paroxetine, a potent nitric oxide synthase inhibitor, for use in the hepatopulmonary syndrome. We present a patient with severe (type II) hepatopulmonary syndrome caused by idiopathic portal hypertension and discuss the consequences of paroxetine therapy.

Recent advances in hepatopulmonary syndrome

Hepatopulmonary syndrome is defined as the clinical triad of advanced liver disease, arterial deoxygenation and intrapulmonary vascular dilatation. Its pathogenesis is not completely understood. Excessive pulmonary nitric oxide production seems to be one of the factors that contribute to the intrapulmonary vascular dilatation. Other mediators such as endothelin-1 and the heme oxygenase-1/carbon monoxide system have recently been found to be important contributors. The major clinical manifestations are arterial hypoxemia, clubbed fingers and spider nevi. Orthodeoxia is the characteristic clinical feature. Contrast-enhanced echocardiography is the preferred screening test. 99mTechnetium macroaggregated albumin (Tc-99m MAA) lung perfusion scan can further specify the diagnosis of hepatopulmonary syndrome and quantify the magnitude of shunting. No clearly effective medical treatments have been found. Although liver transplantation seems feasible to reverse this situation, it is associated with increased postoperative morbidity and mortality. A preoperative arterial oxygen tension of 50 mmHg or less and Tc-99m MAA shunt fractions of 20% or more are strong predictors of postoperative mortality that can be used to stratify patients with better outcome.

Hepatopulmonary syndrome

The hepatopulmonary syndrome is an increasingly important vascular complication of cirrhosis where microvascular dilatation impairs arterial oxygenation in the setting of liver disease. This syndrome is identified in as many as 20% of patients evaluated for liver transplantation and results in increased mortality. No clearly effective medical therapies are available, and liver transplantation is the only established treatment. Pathophysiologic insights obtained from experimental models may lead to the development of novel and effective medical treatments.

Hepatopulmonory syndrome--an uncommon and severe complication of certain liver diseases

Hepatopulmonary syndrome (HPS) is charaterised by arterial hypoxaemia found mainly in association with chronic liver disease (most commonly cirrhosis of liver) but also rarely with acute liver diseases like fulminant hepatic failure or Budd-Chiari syndrome. The purpose of this article is to present an uncommon but grave complication mostly associated with cirrhosis of liver and to differentiate this entry from cyanotic heart diseases or certain lung conditions. Investigations include history and physical examination, certain biochemical tests, upper gastro-intestinal (GI) endoscopy, abdominal ultrasonography, liver biopsy and venacavography in appropriate cases. Finally, the suspected cases underwent arterial blood gas (ABG) analysis and contrast enhanced echocardiography (CEE) for confirmation of the diagnosis of HPS. Of the 123 cases of cirrhosis of liver, three cases of HPS (2.4%) were found-all of them being males. Also one male patient with inferior vena cava (IVC) obstruction amongst other causes presenting with HPS was encountered. As of now, no medical treatment has been proved to be useful and liver transplant remains the only hope for this disorder.

Hepatopulmonary syndrome: report of one case

Hepatopulmonary syndrome consists of a triad of chronic liver disease, hypoxemia, and intrapulmonary vascular dilatation in the absence of primary cardiac or pulmonary diseases. Though this complication has been described in as many as 4-29% of patients with liver disease, its clinical manifestations are often subclinical. The standard diagnostic tests for hepatopulmonary syndrome are the applications of contrast echocardiography and 99mTc lung perfusion scan. In this report, we describe a 19-year-old female with biliary atresia and subsequent liver cirrhosis, who also had the complication of hepatopulmonary syndrome since adolescence. We conclude when the symptoms and signs of hypoxemia appear in a patient with chronic liver disease, the differential diagnosis of hepatopulmonary syndrome should be kept in mind.

[Gasometric alterations in hospitalized cirrhotic patients]

BACKGROUND AND OBJECTIVES

Gas exchange alterations have been described in cirrhotic patients; but by the moment, a few prospective studies have focused in them. The aim of this study was to describe the frequency and severity of gasometric alterations in hospitalized cirrhotic patients, a their correlation with hepatocellular disfunction.

PATIENTS AND METHODS

50 consecutive cirrhotic patients (41 males) admitted for liver decompensation (ascites, liver encephalopathy, alcoholic hepatitis and upper gastrointestinal bleeding) without acute or chronic cardiopulmonary disfunction were included in the study. Patients were classified according with Child-Pugh score (A, n = 13; B, n = 21; C, n = 16). Severe alcoholic hepatitis (SAH) was confirmed in 7 patients. Arterial gasometry was performed in all patients before discharge. Contrast echocardiography was performed in any case of suspicion of hepatopulmonary syndrome (HPS).

RESULTS

Light hypoxemia was observed (80.9 mmHg), without differences with Child-Pugh. Hypocapnia was significantly more evident in Child C than in A and B (31.2 +/- 3.1 vs. 38.1 +/- 4.3 y 36.3 +/- 5 mmHg; p < 0,05), respectively. Cirrhotic patients with SAH showed a significantly higher hypocapnia by comparison with others (31.2 +/- 3.1 vs. a 36.3+/-5 mmHg; p < 0.05). In multivariate analysis, independent prognostic variables for hypocapnica were plasmatic levels of protrombin time, albumin and sodium. HPS was confirmed in 8 patients (16%).

CONCLUSIONS

The most prevalent gas exchange abnormality in cirrhosis was the alteration of alveolar-arterial oxygen tension gradient, directly correlated with hepatocellur disfunction. Hypocapnia could be a compensatory mechanism or the result of the activation of central respiratory centres by non-depurated substances by the liver.