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

Alterations in arterial blood parameters in patients with liver cirrhosis and ascites

In cirrhotic patients, in addition to hepatocytes and Kuppfer cells dysfunction circulatory anatomic shunt and ventilation/perfusion (V(A)/ Q) ratio abnormalities can induce decrease in partial pressure of oxygen in arterial blood (PaO(2)), in oxygen saturation of hemoglobin (SaO(2)) as well as various acid-base disturbances. We studied 49 cases of liver cirrhosis (LC) with ascites compared to 50 normal controls. Causes were: posthepatic 37 (75.51%), alcoholic 7 (14.24%), cardiac 2 (4.08%), and cryptogenic 3 (6.12%). Complications were: upper gastrointestinal bleeding 24 (48.97), hepatic encephalopathy 20 (40.81%), gastritis 28 (57.14%), hepatoma 5 (10.2%), renal hepatic syndrome 2 (4.01%), HbsAg (+) 24 (48.97%), and hepatic pleural effusions 7 (14.28%). Average PaO(2) and SaO(2) were 75.2 mmHg and 94.5 mmHg, respectively, compared to 94.2 mmHg and 97.1 mmHg of the control group, respectively (p value in both PaO(2) and SaO(2 )was p<0.01). Respiratory alkalosis, metabolic alkalosis, metabolic acidosis, respiratory acidosis and metabolic acidosis with respiratory alkalosis were acid-base disturbances observed. In conclusion, portopulmonary shunt, intrapulmonary arteriovenous shunt and V(A)/Q inequality can induce a decrease in PaO(2) and SaO(2) as well as various acid-base disturbances. As a result, pulmonary resistance is impaired and patients more likely succumb to infections and adult respiratory distress syndrome.

Cost-effectiveness of screening for hepatopulmonary syndrome in liver transplant candidates

The hepatopulmonary syndrome (HPS) is present in 15-20% of patients with cirrhosis undergoing orthotopic liver transplantation (OLT) evaluation. Both preoperative and post-OLT mortality is increased in HPS patients particularly when hypoxemia is severe. Screening for HPS could enhance detection of OLT candidates with sufficient hypoxemia to merit higher priority for transplant and thereby decrease mortality. However, the cost-effectiveness of such an approach has not been assessed. Our objective was to perform a cost-effectiveness analysis from a third-party payer's perspective of screening for HPS in liver OLT candidates. The costs and outcomes of 3 different strategies were compared: (1) no screening, (2) screening patients with a validated dyspnea questionnaire, and (3) screening all patients with pulse oximetry. Arterial blood gas analyses and contrast echocardiography were performed in patients with dyspnea or a pulse oximetry (SpO(2)) < or =97% to define the presence of HPS. A Markov model was constructed simulating the natural history of cirrhosis in a cohort of patients 50 years old over a time horizon of their remaining life expectancy. Transition probabilities were obtained from published data available through Medline and U.S. vital statistics. Costs represented Medicare reimbursement data at our institution. Costs and health effects were discounted at a 3% annual rate. No screening was associated with a total cost of 291,898 dollars and a life expectancy of 11.131 years. Screening with pulse oximetry was associated with a cost of 299,719 dollars and a life expectancy of 12.27 years. Screening patients with the dyspnea-fatigue index was associated with a cost and life expectancy of 300,278 dollars and 12.28 years, respectively. The incremental cost-effectiveness ratio of screening with pulse oximetry (compared to no screening) was 6,867 dollars per life year gained, whereas that of the dyspnea-fatigue index (compared to pulse oximetry) was 55,900 dollars per life year gained. The cost-effectiveness of screening depended on the prevalence and severity of HPS, and the choice of screening strategy was dependent on the sensitivity of the screening modality. In conclusion, screening for HPS, especially with pulse oximetry, is a cost-effective strategy that improves survival in transplant candidates predominantly by targeting the transplant to the subgroup of patients most likely to benefit. The utility of screening depends on the prevalence and severity of HPS in the target population.

Two cases of hepatopulmonary syndrome with improved liver function following long-term oxygen therapy

Hepatopulmonary syndrome (HPS) is a complication of liver disease that is characterized by hypoxemia and intrapulmonary vascular dilatations. The only established therapy for this disorder is liver transplantation. Here, we report two patients (a 63-year-old woman and a 72-year-old man) with HPS associated with hepatitis C virus-related cirrhosis. We gave the patients low-dose oxygen supplementation to improve their respiratory symptoms. Surprisingly, their liver function improved from Child Pugh class C to class A, and ascites disappeared after a year of oxygen supplementation. We believe that long-term oxygen therapy contributed to the improvement of liver function in these two cases. Long-term oxygen therapy might offer a new therapeutic approach to improve liver function in patients with cirrhosis with hypoxemia.

Prevalence and prognosis of intrapulmonary shunts in patients with hepatic cirrhosis

We investigated the prevalence of intrapulmonary shunts in 82 patients with hepatic cirrhosis referred for echocardiography as part of liver transplantation evaluation. Intrapulmonary shunts were present in 49 of 82 patients (60%). Baseline characteristics were similar in patients with and without intrapulmonary shunts. Mean follow up was 41 +/- 15 months in patients with intrapulmonary shunts and 42 +/- 15 months in patients without intrapulmonary shunts (P not significant). At follow up, 8 of 49 patients (16%) with intrapulmonary shunts and 4 of 33 patients (12%) without intrapulmonary shunts had died (P not significant).

Hepatopulmonary syndrome increases the postoperative mortality rate following liver transplantation: a prospective study in 90 patients

Hepatopulmonary syndrome (HPS) is a frequent pulmonary complication of patients with end-stage liver diseases. HPS is diagnosed by hypoxemia and pulmonary vascular dilatation and is an independent risk factor of mortality. Orthotopic liver transplantation (OLT) is the only factor that modifies the natural course of HPS. Once patients with HPS have been transplanted, their long-term survival rate is similar to transplanted patients without HPS. Consequently, HPS is an indication of OLT whatever the severity of hypoxemia. However, besides the favorable long-term survival of HPS patients with OLT, a high postoperative mortality (mostly within 6 months) has been suggested. The aim of our study was to analyze the incidence of HPS and postoperative outcome after OLT in 90 consecutive patients. All patients were prospectively included and had blood gas analysis to detect HPS. Patients with hypoxemia had contrast echocardiography to confirm HPS. Nine patients had HPS with a 50 </= PaO(2)</= 70 mmHg. Among them 3 (33%) died while the mortality rate was 9.2% in the group without HPS (7 over 76 patients). In the HPS patients who survived, the syndrome completely recovered within 6 months. In conclusion, our study shows a high postoperative mortality rate following OLT even though the preoperative PaO(2) was >50 mmHg in all HPS patients transplanted.

Outpatient Management of Cirrhosis: A Narrative Review

Cirrhosis is the 12th leading cause of death in the United States. Individuals with cirrhosis are at risk for many potential complications. Complications can be managed or detected early with proper outpatient management. The most lethal of these complications is bleeding esophageal varices. All patients with cirrhosis should be screened for the presence of varices and treated when indicated. The most common complication seen in these patients is ascites. Ascites can be treated with dietary modifications and a diuretic regimen. Other potential complications include spontaneous bacterial peritonitis, hepatocellular carcinoma, hepatic encephalopathy, hepatorenal syndrome, and hepatopulmonary syndrome. The outpatient management of these complications will be discussed in this paper, along with the use of vaccinations, educating patients about the avoidance of hepatotoxic drugs, and when to refer a patient for liver transplant.

Hepatopulmonary syndrome

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

The diagnosis and treatment of hepatopulmonary syndrome

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

Effect of oral garlic on arterial oxygen pressure in children with hepatopulmonary syndrome

AIM: To study the effect of oral garlic on arterial oxygen pressure in children with hepatopulmonary syndrome.

METHODS: Garlic powder in a capsule form was given to 15 children with hepatopulmonary syndrome (confirmed by contrast echocardiography) at the dosage of 1 g/1.73 m² per day. Patients were evaluated clinically and by arterial blood gas every four weeks.

RESULTS: The garlic capsule was administered to 15 patients with hepatopulmonary syndrome. There were 10 boys and 5 girls with a mean age of 9.4 ± 3.9 years. The underlying problems were biliary tract atresia (4 patients), autoimmune hepatitis (4 patients), cryptogenic cirrhosis (4 patients) and presinusoidal portal hypertension (3 patients). Eight patients (53.3%) showed an increase of 10 mmHg in their mean arterial oxygen pressure. The baseline PaO₂ was 65.6 ± 12.1 mmHg in the responder group and 47.1 ± 11.2 mmHg in non-responder group. At the end of treatment the mean PaO₂ in responders and non-responders was 92.2 ± 7.75 mmHg and 47.5 ± 11.87 mmHg, respectively (P < 0.01).

CONCLUSION: Garlic may increase oxygenation and improve dyspnea in children with hepatopulmonary syndrome.

Congenital portocaval fistula associated with hepatopulmonary syndrome: ligation vs liver transplantation

A 4-year-old boy underwent pulmonary testing for diagnosis of exercise-induced dyspnea and subsequent cyanosis. Findings demonstrated the presence of multiple pulmonary arteriovenous fistulas resulting in oxygen desaturation owing to shunting (PaO2, 44 mm Hg). Abdominal ultrasound, abdominal computer tomography, and mesenteric angiography revealed an extrahepatic portocaval fistula (PCF), absence of a patent portal vein, and no evidence of portal hypertension. Because these findings were consistent with hepatopulmonary syndrome (HPS), liver transplantation was initially considered. However, subsequent workup using cavofistulography revealed the presence of a hypoplastic portal vein that selective catheterization showed to be threadlike but patent. Based on this finding, a definitive diagnosis of a congenital PCF with hypoplasia of the portal vein (type 2 Abernethy malformation) was made and surgical ligation with transection of the fistula was performed at the age of 5. Treatment was successful without subsequent development of portal hypertension and pulmonary symptoms disappeared. Follow-up examination 4 years later showed that the boy was asymptomatic and that the intrahepatic portal system was patent with normal hepatopetal flow. This is the first reported case of HPS because of portal type 2 Abernethy malformation. Anatomical types of PCF and corresponding therapeutic options in case of HPS are discussed.

Cardiopulmonary complications in chronic liver disease

Patients with cirrhosis and portal hypertension exhibit characteristic cardiovascular and pulmonary hemodynamic changes. A vasodilatatory state and a hyperdynamic circulation affecting the cardiac and pulmonary functions dominate the circulation. The recently defined cirrhotic cardiomyopathy may affect systolic and diastolic functions, and imply electromechanical abnormalities. In addition, the baroreceptor function and regulation of the circulatory homoeostasis is impaired. Pulmonary dysfunction involves diffusing abnormalities with the development of the hepatopulmonary syndrome and portopulmonary hypertension in some patients. Recent research has focused on the assertion that the hemodynamic and neurohumoral dysregulation are of major importance for the development of the cardiovascular and pulmonary complications in cirrhosis. This aspect is important to take into account in the management of these patients.

Evaluation of intrapulmonary vascular dilatations with high-resolution computed thorax tomography in patients with hepatopulmonary syndrome

GOALS

We aimed to determine the role of thorax high-resolution computed tomography (HRCT) in demonstrating the pulmonary vasodilatation in patients with hepatopulmonary syndrome (HPS).

BACKGROUND

Traditionally, the presence of intrapulmonary vascular dilatations can be detected by using one of the three diagnostic modalities: contrast-enhanced echocardiography, technetium 99 m-labeled macroaggregated albumin scan, and pulmonary angiography.

STUDY

The study group included 10 patients with HPS (Group 1), 12 patients with normoxemic cirrhosis (Group 2), and 12 healthy controls (Group 3). All of the subjects underwent conventional and HRCT of thorax. The diameters of pulmonary trunk, main pulmonary arteries, and right lower lobe basal segmental arteries were measured. The ratios of right lower lobe basal segmental pulmonary artery to bronchus diameter were calculated.

RESULTS

The mean diameters of the main pulmonary trunk, right and left main pulmonary arteries were not different between the groups. Mean diameters of right lower lobe basal segmental pulmonary arteries were significantly higher in Group 1 compared with Group 2 (P=0.01) and Group 3 (P=0.002). Mean right lower lobe basal segmental pulmonary artery to bronchus ratios were significantly higher in Group 1 compared with Group 2 (P=0.03) and Group 3 (P<0.001). Group 2 had significantly higher pulmonary artery to bronchus ratios than Group 3 (P<0.001).

CONCLUSIONS

Thorax HRCT may be helpful in the diagnosis of HPS by demonstrating the dilated peripheral pulmonary vessels or increased pulmonary artery to bronchus ratios in patients with liver disease and hypoxemia.

Exercise induced arterial hypoxemia: the role of ventilation-perfusion inequality and pulmonary diffusion limitation

Many apparently healthy individuals experience pulmonary gas exchange limitations during exercise, and the term "exercise induced arterial hypoxemia" (EIAH) has been used to describe the increase in alveolar-arterial difference for oxygen (AaDO2), which combined with a minimal alveolar hyperventilatory response, results in a reduction in arterial PO2. Despite more than two decades of research, the mechanisms of pulmonary gas exchange limitations during exercise are still debated. Using data in 166 healthy normal subjects collated from several previously published studies it can be shown that approximately 20% of the variation in PaO2 between individuals can be explained on the basis of variations in alveolar ventilation, whereas variations in AaDO2 explain approximately 80%. Using multiple inert gas data the relative contributions of ventilation-perfusion ("VA/Q") inequality and diffusion limitation to the AaDO2 can be assessed. During maximal exercise, both in individuals with minimal (AaDO2 < 20 Torr, x = 13 +/- 5, means +/- SD, n = 35) and moderate to severe (AaDO2= 25-40 Torr, x = 33 +/- 6, n = 20) gas exchange limitations, VA/Q inequality is an important contributor to the AaDO2. However, in subjects with minimal gas exchange impairment, VA/Q inequality accounts for virtually all of the AaDO2 (12 +/- 6 Torr), whereas in subjects with moderate to severe gas exchange impairment it accounts for less than 50% of the AaDO2 (15 +/- 6 Torr). Using this framework, the difficulties associated with unraveling the mechanisms of pulmonary gas exchange limitations during exercise are explored, and current data discussed.

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.

Diffuse Pulmonary Arteriovenous Malformations in a Teenager with Corrected Total Anomalous Pulmonary Venous Drainage

This case report describes a 13-year-old boy with diffuse microvascular pulmonary arteriovenous malformations, in whom total anomalous pulmonary venous drainage had been corrected surgically in the newborn period. Contrast transesophageal echocardiography, cardiac catheterization and a lung perfusion scan suggested, and lung biopsy confirmed the diagnosis in our patient. Treatment with nifedipin was commenced.

CONCLUSION

This case illustrates the diagnostic difficulties with this rare malformation.

Arterial hypoxemia and intrapulmonary vasodilatation in rat models of portal hypertension

BACKGROUND

Rats with chronic bile duct ligation (CBDL) and portal vein ligation (PVL) are used as models of portal hypertension. CBDL rats show hypoxemia with intrapulmonary vasodilatation (IPVD), and are recognized as a model of hepatopulmonary syndrome (HPS), while PVL rats are normoxemic. We investigated the differences in arterial oxygenation between these models, and the key factors leading to HPS.

METHODS

Forty-eight Sprague-Dawley rats were prepared as CBDL or PVL models, or as Sham rats. Arterial oxygenation, hemodynamics (reference sample method), and IPVD were simultaneously evaluated in conscious and unrestrained animals, using (141)Ce- or (113)Sn-labeled microspheres (15 microm in diameter), respectively. Endothelin-1 (ET-1) and nitrate/nitrite (end products of nitric oxide; NOx) production by the lung tissue (increment across the lungs) was also determined.

RESULTS

The extent of IPVD was similar in both models, but hypoxemia was only observed in CBDL rats. The ET-1 level and the increment in NOx were significantly increased in CBDL rats, and the increment was directly correlated with impairment of oxygenation. Blood flow through the bronchial arteries (anatomical shunting) was increased in CBDL rats, reaching more than three times the level in PVL rats or Sham rats.

CONCLUSIONS

These results support the hypothesis that NO derived from the lung tissues contributes to hypoxemia, and IPVD appears to be a prerequisite for impaired oxygenation. The considerable increase of anatomical shunting may potentially contribute to impaired oxygenation in CBDL rats.

Carboxyhemoglobin levels in cirrhotic patients with and without hepatopulmonary syndrome

BACKGROUND AND AIMS

Heme oxygenase (HO) catalyzes hemoglobin into bilirubin, iron, and carbon monoxide (CO), a known vasodilator. HO expression and CO production as measured by blood carboxyhemoglobin (COHb) levels increase in experimental hepatopulmonary syndrome (HPS) and contribute to vasodilatation. Whether CO contributes to HPS in humans is unknown. Our aim was to assess if arterial COHb levels are increased in cirrhotic patients with HPS relative to those without HPS.

METHODS

We collected data prospectively in stable nonsmoking outpatients with cirrhosis. Demographic and clinical data and room-air arterial blood gases were collected and analyzed. HPS was diagnosed using established criteria.

RESULTS

A total of 159 patients were studied. HPS was present in 27 (17%) patients. Mean age was 52 +/- 9 years, 54% were men, and hepatitis C and/or alcohol were the most common causes (53%). Fourteen percent were Child-Pugh class A, 53% were Child-Pugh class B, and 33% were Child-Pugh class C. Demographic and clinical features were similar between HPS and non-HPS patients except for the Child-Pugh score, which was lower in patients with HPS. Arterial Pa o 2 levels were lower and the alveolar-arterial oxygen gradient was higher in patients with HPS ( P < .001). COHb levels were increased in HPS relative to non-HPS ( P < .001) and correlated with Pa o 2 ( P < .001) and Aa po 2 ( P < .001) levels.

CONCLUSIONS

COHb levels are increased in cirrhotic patients with HPS and correlate with gas exchange abnormalities. These results are consistent with findings in experimental HPS and suggest that CO may contribute to human HPS.

Development of hypoxemia in alcoholic liver disease

The aim of this study was to investigate the arterial hypoxemia in Japanese patients with alcoholic liver disease (ALD) with regard to alcohol consumption and/or disease severity. Hypoxemia was observed in 78% patients with ALD and in all 46 patients with alcoholic liver cirrhosis (ALC) and 33 (56%) of 59 patients with noncirrhotic alcoholic liver disease (NCALD) (P < 0.0001). The partial pressure of oxygen (PaO2) was 71.1 +/- 5.2 mm Hg in ALC and 78.7 +/- 6.3 mm Hg in NCALD (P < 0.0001). The oxygen consumption in ALD was significantly higher than that in control subjects (P < 0.0001), and a high oxygen consumption was seen in 88% of the patients with ALD, in all 46 ALC patients, and in 46 (78%) of 59 NCALD patients (P < 0.01). Following abstinence from alcohol, the PaO2 and oxygen consumption significantly recovered after day 2 (P < 0.0001), whereas the prothrombin index did not change in either NCALD or ALC patients. Multivariate analysis showed that alcohol consumption and oxygen consumption were significant independent predictors of PaO2. In conclusion, the present findings suggest that increased oxygen consumption due to alcohol ingestion is principally responsible for the hypoxemia in ALD patients.

The Incidence of self-prescribed oral complementary and alternative medicine use by patients with gastrointestinal diseases

GOALS

To assess the incidence of oral complementary and alternative medicine (CAM) usage by gastroenterology patients at a single university center and compare against controls.

BACKGROUND

The public awareness and usage of CAM have increased. The use of CAM has been described in patients with functional bowel disorders; however, their role in patients with gastrointestinal disease is less clear.

STUDY

Patients attending luminal gastroenterology clinics and customers at local supermarkets completed a 30-point, structured questionnaire assessing their use of CAM.

RESULTS

A total of 1,409 subjects were recruited. The incidence of CAM use was 49.5% for inflammatory bowel disease, 50.9% for irritable bowel syndrome, 20% for general gastrointestinal diseases, and 27% for controls. Pearson's chi(2) tests showed that patients with inflammatory bowel disease (IBD) or irritable bowel syndrome were more likely to use CAM than controls (P < 0.001). Binary logistic regression analysis showed that females were more likely to take CAM than men (P < 0.05).

CONCLUSIONS

The percentage of CAM users among patients with IBD is similar to those with a functional diagnosis. Increasing numbers of IBD patients are using CAM in addition to conventional therapy. Awareness of this may prevent adverse CAM and conventional drug interactions.

Síndrome hepatopulmonar: patogenia, diagnóstico e tratamento

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

Hepatopulmonary syndrome

The hepatopulmonary syndrom occurs when pulmonary microvacular dilatation causes hypoxemia in cirrhosis. It is found in between 15-20% of patients with chronic liver diseases and should be considered in the differential diagnosis of dyspnea or abnormal arterial oxygenation in this group. The presence of HPS appears to significantly increase mortality in affected patients with cirrhosis. The mediators of intrapulmonary vasodilatation and HPS are not fully characterized although pulmonary nitric oxide overproduction appears to be a key event in human and experimental models. Contrast echocardiography is the best screening test for pulmonary vasodilatation. Currently there are no effective medical therapies for HPS, although liver transplantation results in reversal of HPS in most cases. However, mortality is higher in patients with HPS undergoing transplantation relative to those without HPS.

Characteristics and prevalence of intrapulmonary shunt detected by contrast echocardiography with harmonic imaging in liver transplant candidates

We investigated the prevalence and characteristics of intrapulmonary shunt using contrast echocardiography with harmonic imaging in 130 liver transplant candidates. We found a high prevalence of intrapulmonary shunts and a significant correlation between the degree of intrapulmonary shunt and the Child-Pugh classification score.

Anesthetic considerations during liver surgery

This article demonstrates the broad range of considerations that affect the outcome of patients undergoing hepatectomy. The progressive improvements in survival, despite the increasing complexity of the surgery, area testament to advances in both surgery and anesthesia. The key elements include careful patient selection, appropriate monitoring, and mechanical and pharmacologic protection of the liver and other vital organs.

Hepatopulmonary syndrome: a concern for the anesthetist? Pre-operative evaluation of hypoxemic patients with liver disease

Liver cirrhosis and other chronic hepatic diseases are followed in a subset of affected patients by gas exchange abnormalities resulting from a syndrome called hepatopulmonary syndrome (HPS). The structural basis of this clinical entity is an alteration of pulmonary vasculature resulting in abnormal vasodilatation and mismatching of ventilation and perfusion of the lung. Dilatation of the capillary bed near the gas exchange area is the most important factor implicated; it precludes O2 molecules diffusing to the centrum of the dilated vessels to oxygenate venous blood. Contrast (microbubbles) echocardiography and lung perfusion scan are, respectively, the screening tests with the highest sensitivity and specificity for HPS diagnosis. Because of the high morbidity and mortality of HPS, clinicians have been trying to understand the pathophysiology of pulmonary vasodilatation in the hope that the process can be reversed pharmacologically or surgically. An imbalance between production and clearance of vasoactive circulating substances has been implicated in the pathogenesis of HPS with glucagon and nitric oxide among the principal responsible factors. To date various molecules have been implicated for therapy but without definitive positive results. Liver transplantation remains the only real therapy for HPS, and resolution of gas exchange defects outlines the possible functional reversible nature of vascular abnormalities of this syndrome. The need to perform surgery under general anesthesia for hepatic and extrahepatic procedures in patients with HPS is followed by an increased peri-operative risk. The authors emphasize the role of pre-operative clinical evaluation for proper patient management during the peri-operative period.

Frequency, clinical characteristics, and respiratory parameters of hepatopulmonary syndrome

OBJECTIVES

To determine the frequency and the clinical characteristics of hepatopulmonary syndrome (HPS) in cirrhotic candidates for orthotopic liver transplantation and to identify the major respiratory parameters predictive of the presence of changes in arterial oxygenation.

PATIENTS AND METHODS

Patients underwent transthoracic contrast-enhanced echocardiography, pulmonary scintigraphy, pulmonary function test with diffusing capacity of lung for carbon monoxide (DLCO), and measurement of arterial blood gases.

RESULTS

Fifty-six patients were studied. Twenty-five patients (45%) presented with intrapulmonary vascular dilatations, but only 9 (16%) fulfilled the criteria for HPS. The clinical or demographic characteristics considered did not differ in the patients with and without HPS. The DLCO value was significantly lower in patients with HPS (P=.01). However, 32 (80%) of 40 patients with low DLCO values did not fulfill the criteria for HPS. An alveolar arterial oxygen gradient (AaPO2) of more than 20 mm Hg showed a higher diagnostic accuracy (91%) in the assessment of HPS than did the DLCO of less than 80% predicted (41%) and the AaPO2 of more than 15 mm Hg (71%).

CONCLUSIONS

The AaPO2 proved to be a more reliable index than PaO2 and DLCO for the determination of changes in arterial oxygenation in HPS. The DLCO does not seem to be a good marker for HPS screening. Intrapulmonary vascular dilatations were frequent, even in patients who did not fulfill the criteria for HPS.

Prognostic significance of the hepatopulmonary syndrome in patients with cirrhosis

BACKGROUND AND AIMS

The hepatopulmonary syndrome (HPS) has been defined by chronic liver disease, arterial deoxygenation, and widespread intrapulmonary vasodilation. Mortality of patients with HPS is considered to be high, but the effect of HPS on survival in patients with cirrhosis remains unclear.

METHODS

A total of 111 patients with cirrhosis were studied prospectively by using transthoracic contrast echocardiography for detection of pulmonary vasodilation, blood gas analysis, and pulmonary function test. Twenty different clinical characteristics and survival times were noted.

RESULTS

Twenty-seven patients (24%) had HPS. Their mortality was significantly higher (median survival, 10.6 months) compared with patients without HPS (40.8 mo, P < 0.05), even after adjusting for liver disease severity (2.9 vs. 14.7 months in Child-Pugh class C with [n = 15] and without HPS [n = 35, P < 0.05]; 35.3 vs. 44.5 months in Child-Pugh class B with [n = 7] and without HPS [n = 23, P = NS]), and exclusion of patients who underwent liver transplantation during follow-up (median survival 4.8 vs. 35.2 months, P = 0.005). Causes of death were mainly nonpulmonary and liver-related in the 19 patients with and the 35 patients without HPS who died. In multivariate analysis, HPS was an independent predictor of survival besides age, Child-Pugh class, and blood urea nitrogen. Mortality correlates with severity of HPS.

CONCLUSIONS

The presence of HPS independently worsens prognosis of patients with cirrhosis. This should influence patient management and scoring systems and accelerate the evaluation process for liver transplantation.

Prospective evaluation of outcomes and predictors of mortality in patients with hepatopulmonary syndrome undergoing liver transplantation

The hepatopulmonary syndrome (HPS) occurs in a subgroup of patients with cirrhosis and results from intrapulmonary vasodilatation, which may cause significant hypoxemia. Liver transplantation has emerged as a therapeutic option for patients with HPS based on retrospective case series and reports. However, morbidity and mortality appear to be increased after transplantation for HPS, and no prospective studies evaluating clinical features that may predict poor surgical outcome are available. Therefore, we prospectively evaluated the utility of the degree of hypoxemia, the arterial oxygen response to 100% oxygen administration, and the macroaggregated albumin (MAA) scan quantification of intrapulmonary shunting as predictors for outcome after liver transplantation. Our cohort consisted of 24 patients with cirrhosis and HPS who underwent liver transplantation over a 5-year period at 2 transplant centers who were followed at least 1 year after transplantation. All patients underwent preoperative evaluation for HPS with standardized methods. Seven patients (29%) died postoperatively, 5 of cardiorespiratory complications. All deaths occurred within 10 weeks after transplantation. A preoperative arterial oxygen tension (PaO(2)) of </= 50 mm Hg alone or in combination with a MAA shunt fraction >/= 20% were the strongest predictors of postoperative mortality. In conclusion, we found that mortality is increased after liver transplantation for HPS, particularly in patients with more severe hypoxemia and significant intrapulmonary shunting. Preoperative testing for the severity of HPS can be used to stratify patients according to the risk for postoperative mortality.

Abernethy malformation: one of the etiologies of hepatopulmonary syndrome

Hepatopulmonary syndrome (HPS) is the clinical relationship between hepatic disease and the existence of pulmonary vascular dilatations, which can result in a range of arterial oxygenation abnormalities. It is probably caused by an alteration in the synthesis or metabolism of vasoactive pulmonary substances at a hepatic level, leading to vasodilatation of pulmonary vessels and diffusion perfusion defects. The Abernethy malformation is characterized by the congenital diversion of portal blood away from the liver, by either end-to-side or side-to-side shunt. Here, we report on a 5-year-and-11-month-old-boy who had started cyanosis at age 4 years and 11 months, and did not have any other pulmonary or cardiac signs or symptoms. In the investigation, arterial blood gases revealed a PaO(2) of 41.4 mm Hg. The chest x-ray film and echo Doppler cardiography were normal. Nuclear scanning with Technetium 99m-labeled macroaggregated albumin showed the presence of arteriovenous shunt, at 47%. Abdominal echography revealed Abernethy malformation with an absence of portal vein. We concluded that the patient had HPS caused by Abernethy malformation. The possible mechanism is that in this malformation, there is a deviation in the blood that comes from the spleen to the vena cava without passing through the liver, so there is no metabolism of some substances which can be responsible for the imbalance between the vasodilatation and the vasoconstriction of the pulmonary circulation. Abernethy malformation must be included as one of the etiologies of hepatopulmonary syndrome. This is the first case described in the literature with this form of presentation.

Pulmonary gas exchange abnormalities in liver transplant candidates

Abnormal diffusing capacity is the commonest pulmonary dysfunction in liver transplant candidates, but severe hypoxemia secondary to hepatopulmonary syndrome and significant pulmonary hypertension are pulmonary vascular manifestations of cirrhosis that may affect the perioperative course. We prospectively assessed the extent of pulmonary dysfunction in patients referred for liver transplantation. A total of 57 consecutive patients with chronic liver disease were evaluated. All patients had a chest radiograph, standing arterial blood gas on room air, pulmonary function testing, and Doppler echocardiogram. Those patients with arterial hypoxaemia (PaO(2) < 10 kPa) also underwent (99m)Tc-macroaggregated albumin lung scan, and nine patients had agitated normal saline injection during echocardiography to define further the existence of pulmonary vascular dilatation. Reduced diffusing capacity for carbon monoxide less than 75% of the predicted value was found in 29 of 57 (51%) patients. Although elevated alveolar-arterial oxygen tension difference was detected in 35% (20/57) of the patients, only four (7%) patients had hypoxemia. We were unable to find evidence of intrapulmonary vascular dilatation either on the lung scan or saline-enhanced echocardiography in any of these patients. Reduction in diffusing capacity for carbon monoxide was noted in 75% (18/24) of patients who were transplanted for primary biliary cirrhosis and was accompanied by widened alveolar-arterial oxygen tension in 10 out of 18 (56%) of patients. This study shows that in liver transplant candidates, diffusion impairment and widened alveolar-arterial oxygen tension difference were frequently detected, especially in patients with primary biliary cirrhosis.

Update on ascites and hepatorenal syndrome

Ascites is the most common complication occurring during liver cirrhosis. Even if a significant decrease in renal clearance may be observed in the first step of chronic active liver disease, renal impairment, at times complicated by the typical signs of hepatorenal syndrome, occurs only in patients with ascites, especially when tense and refractory. Experimental and clinical data seem to suggest a primary sodium and water retention in the pathogenesis of ascites, in the presence of an intrahepatic increase of hydrostatic pressure, which, by itself, physiologically occurs during digestion. Abnormal sodium and water handling leads to plasma volume expansion, followed by decreased peripheral vascular resistance and increased cardiac output. This second step is in agreement with the peripheral arterial vasodilation hypothesis, depicted by an increase in total blood volume, but with a decreased effective arterial blood volume. This discrepancy leads to the activation of the sympathetic nervous and renin-angiotensin-aldosterone systems associated with the progressive activation of the renal autacoid systems, especially, that of the arachidonic acid. During advanced cirrhosis, renal impairment becomes more sustained and renal autacoid vasodilating substances are less available, possibly due to a progressive exhaustion of these systems. At the same time ascites becomes refractory inasmuch as it is no longer responsive to diuretic treatment. Various pathogenetic mechanisms leading to refractory ascites are mentioned. Finally, several treatment approaches to overcome the reduced effectiveness of diuretic therapy are cited. Paracentesis, together with simultaneous administration of human albumin or other plasma expanders is the main common approach to treat refractory ascites and to avoid a further decrease in renal failure. Other effective tools are: administration of terlipressin together with albumin, implantation of the Le Veen shunt, surgical porto-systemic shunting or transjugular intrahepatic portosystemic stent-shunt, or orthotopic liver transplantation, according to the conditions of the individual patient.

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.

Noninvasive investigation of hepatopulmonary syndrome in children and adolescents with chronic cholestasis

Early detection of hepatopulmonary syndrome (HPS) may be delayed because of invasiveness of the diagnostic procedures. In this pilot study, we prospectively investigated the usefulness of determining transcutaneous O(2) tension after 100% O(2) (TcPO(2)100) breathing using a transcutaneous hyperoxia test (THT) in 11 children with chronic cholestasis and without primary cardiopulmonary disease. These patients also underwent alveolar-arterial O(2) gradient testing (AaDO(2)) at an inspired oxygen fraction (FiO(2)) of 0.21, lung scintiscan, and contrast transthoracic echocardiography (TTE). Three of them had a liver transplantation because of the downhill course of their liver disease and respiratory status. THT transcutaneous O(2) tension at 21% FiO(2) (TcPO(2)21) was 75 +/- 13 mm Hg, and increased to 488 +/- 106 mmHg after 100% O(2) breathing (TcPO(2)100). Both mean values were not significantly different from those found in 8 age-matched controls (P = 0.9 and P = 0.5, respectively). However, one patient, in spite of her stable liver function, showed an abnormal TcPO(2)21 and TcPO(2)100 (45 mmHg and 210 mmHg, respectively). This same subject was also the only patient with abnormalities of AaDO(2) (54.2 mm Hg; normal value, < 20 mm Hg), lung scintiscan (brain/lung ratio of technetium-99 fixation (B/L SI) = 9, normal value < 1), and TTE, suggesting intrapulmonary vasodilatations and shunts. Given the clinical development of cyanosis and platypnea, all criteria for HPS were fulfilled, and timing of her liver transplantation was therefore accelerated. This resulted in HPS regression. In children with chronic cholestasis, repeated transcutaneous bedside measurements are a rapid and reliable noninvasive test for characterizing the severity of abnormal oxygenation, and may prove useful also in liver posttransplantation monitoring.

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.

[Hepatopulmonary syndrome in liver transplantation candidates]

BACKGROUND

Hepatopulmonary syndrome is an important clinical problem associated with chronic liver disease. Liver transplantation can result in complete resolution of the arterial hypoxemia associated with this syndrome, even in its most severe presentation.

AIM

To determine the prevalence of hepatopulmonary syndrome in adult liver transplant candidates.

PATIENTS AND METHODS

Fifty-four consecutives adult patients (> or = 18 years) with severe liver disease waiting for liver transplant were screened for arterial hypoxemia (PaO2 < 70 mm Hg) while they were seated, at rest, and breathing room air. Patients with arterial hypoxemia underwent contrast-enhanced two-dimensional echocardiography and pulmonary function testing. Hypoxemia (PaO2 < 70 mm Hg) was present in 7 of 54 patients (12.9%), although only 1 of them complained of dyspnea. The Child's classification of the patients were: A = 1, B = 4, and C = 1. All seven hypoxemic patients had positive contrast-enhanced two-dimensional echocardiography, consistent with hepatopulmonary syndrome.

CONCLUSION

The prevalence of hepatopulmonary syndrome in adult liver transplant candidates is elevated. The screening for hepatopulmonary syndrome should be part of the routine evaluation of liver transplant candidates even in the absence of pulmonary symptoms.

Implications of estradiol and progesterone in pulmonary vasodilatation in cirrhotic patients

The derangement of sex hormone serum levels in cirrhotic patients is well-delineated, and increased levels of progesterone and estradiol have been associated to hyperventilation in cirrhotic patients. These hormones have a well-known role in the regulation of vascular tone. The aim of this study was to evaluate whether sex hormone levels contribute to pulmonary vasodilatation (PV) and gas exchange abnormalities in cirrhosis. Contrast transesophageal echocardiography, arterial blood gases, parameters of liver function, pulmonary function test, estradiol and progesterone levels were determined in 45 male cirrhotic patients. Nineteen of 45 patients (42.2%) presented PV. Hyperventilation (pressure arterial of CO2< or =35 mmHg) was correlated to progesterone levels (p<0.05) and pressure arterial of CO2 was high in patients with PV (p<0.005) and Child class B and C (p<0.01). Hypoxemia (pressure arterial of O2<80 mmHg) had inverse correlation with progesterone (p<0.05) and estradiol (p<0.05) levels and pressure arterial of O2 was low in patients with Child class B and C (p<0.05). PV was present in patients with high estradiol levels (p<0.05), high progesterone levels (p<0.005) and Pugh class B and C (p<0.05). Logistic regression analysis identified progesterone as the sole independent factor associated to PV (p<0.0005). Multivariate linear regression showed that PV was the sole independent factor related to both pressure arterial of CO2 (p<0.05) and pressure arterial of O2 (p<0.01) levels. PV was independently associated to gas exchange abnormalities in cirrhosis. Progesterone and estradiol were related with PV in cirrhotic patients.