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

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.

Development of intrapulmonary arteriovenous shunting in postoperative biliary atresia: evaluation by contrast-enhanced echocardiography

PURPOSE

This report presents biliary atresia (BA) patients with intrapulmonary arteriovenous shunting (IPS), which was evaluated suitably by contrast-enhanced echocardiography (CEC).

METHODS

Of 88 BA patients seen in the last 20 years, 8 (9.1%) had IPS at 8 months to 16 years of age. Two were associated with polysplenia syndrome, 1 had persistent jaundice after hepatic portoenterostomy, and 2 underwent splenorenal shunt. According to the comparison between microbubbles in left atrium (LA) and in right atrium (RA) detected by CEC, IPS was classified as grade I, mild (LA << RA); grade II, moderate (LA < RA); grade II, severe (LA = RA).

RESULTS

Grade I consisted of 4 patients whereas grade II and III held 2 patients each. Clinical symptoms such as cyanosis, exertional dyspnea, or clubbing were present in 50% of grade I and all of grade II and IlI. Mean PaO2 in grade I, II, and III was 70.5, 50.4, and 35.3 mm Hg, respectively. In 1 patient with grade I, IPS spontaneously disappeared, but pulmonary hypertension developed later. One patient in grade II died of pulmonary complications, and the other is considered a candidate for livertransplantation (LTx). One patient in grade III died of liver failure, whereas the other is free of IPS after LTx.

CONCLUSION

IPS can lead to a life-threatening complication in postoperative BA patients, and CEC may be a convenient and useful method to evaluate the degree of IPS and determine therapeutic strategy.

Thoracic manifestations associated with advanced liver disease

Advanced liver disease and portal hypertension may produce various intrathoracic complications that involve the pleural space, lung parenchyma, and pulmonary circulation. Dyspnea and arterial hypoxemia are the common clinical symptoms and signs in patients with such complications. In these patients, intrathoracic complications most often develop during the course of hepatic disease, but a few patients may be seen first with respiratory symptoms or radiographic abnormalities. Therefore, radiologists should be made aware of these disorders that occur in patients with chronic liver disease. In this article, the authors describe and illustrate the clinical and imaging spectrum of thoracic abnormalities associated with advanced liver disease and portal hypertension.

Hepatopulmonary syndrome: a prospective study of relationships between severity of liver disease, PaO(2) response to 100% oxygen, and brain uptake after (99m)Tc MAA lung scanning

BACKGROUND

Because of the spectrum of intrapulmonary vascular dilation that characterizes hepatopulmonary syndrome (HPS), PaO(2) while breathing 100% oxygen varies. Abnormal extrapulmonary uptake of (99m)Tc macroaggregated albumin (MAA) after lung perfusion is common.

GOAL

To describe relationships between (1) severity of liver disease measured by the Child-Pugh (CP) classification; (2) PaO(2) while breathing room air (RA) and 100% oxygen on 100% oxygen; and (3) extrapulmonary (brain) uptake of (99m)Tc MAA after lung scanning.

METHODS AND PATIENTS

We prospectively measured PaO(2) on RA, PaO(2) on 100% oxygen, and brain uptake after lung perfusion of (99m)Tc MAA in 25 consecutive HPS patients.

RESULTS

Mean PaO(2) on RA, PaO(2) on 100% oxygen, PaCO(2) on RA, and (99m)Tc MAA brain uptake were similar when categorized by CP classification. Brain uptake was abnormal (> or = 6%) in 24 patients (96%). Brain uptake was 29 +/- 20% (mean +/- SD) and correlated inversely with PaO(2) on RA (r = -0.57; p<0.05) and PaO(2) on 100% oxygen (r = -0.41; p<0.05). Seven patients (28%) had additional nonvascular pulmonary abnormalities and lower PaO(2) on 100% oxygen (215+/-133 mm Hg vs 391+/-137 mm Hg; p<0.007). Eight patients (32%) died. Mortality in patients without coexistent pulmonary abnormalities was associated with greater brain uptake of (99m)Tc MAA (48+/-18% vs 25+/-20%; p<0.04) and lower PaO(2) on RA (40+/-7 mm Hg vs 57+/-11 mm Hg; p<0.001).

CONCLUSION

The degree of hypoxemia associated with HPS was not related to the CP severity of liver disease. HPS patients with additional nonvascular pulmonary abnormalities exhibited lower PaO(2) on 100% oxygen. Mortality was associated with lower PaO(2) on RA, and with greater brain uptake of (99m)Tc MAA.

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.

Intrapulmonary arteriovenous shunting may be a universal phenomenon in patients with the superior cavopulmonary anastomosis: a radionuclide study

OBJECTIVE

To evaluate the extent of intrapulmonary right to left shunting in children after bidirectional cavopulmonary anastomosis (BCPA).

DESIGN

Prospective study of patients who underwent BCPA in a single centre.

PATIENTS

17 patients with complex cyanotic congenital cardiac malformations who underwent BCPA at 1-45 months of age (median 21 months) were evaluated 15-64 months postoperatively (median 32 months). Five children between 1 and 10 years (median 5 years) with normal or surgically corrected intracardiac anatomy and peripheral pulmonary circulation who required V/Q scanning for other reasons were used as controls.

INTERVENTIONS

All patients underwent cardiac catheterisation to exclude angiographically demonstrable venovenous collaterals followed by pulmonary perfusion scanning using (99m)technetium ((99m)Tc) labelled albumen microspheres to quantify the intrapulmonary right to left shunt.

MAIN OUTCOME MEASURE

Percentage of intrapulmonary right to left shunt.

RESULTS

The mean (SD) level of physiological right to left shunting found in the control group was 5.4 (2.3)%. All patients with BCPA showed the presence of a significantly higher level of intrapulmonary shunting (26.8 (16.9)%, p < 0.001). The degree of shunting was significantly increased in the subgroup of 11 patients with BCPA as the only source of pulmonary blood flow (34.9 (15.8)%), when compared to the six remaining patients with an additional source of pulmonary blood supply (12.0 (2.6)%, p < 0.001). There was a negative correlation between age at BCPA and the shunt percentage found in the patients with a competitive source of pulmonary blood flow (r = -0.63, p < 0. 01).

CONCLUSIONS

Intrapulmonary right to left shunting develops in all patients following BCPA. This may be caused by a sustained and inappropriate vasodilatation resulting from absence or decreased levels of a substance that inhibits pulmonary vasodilatation. Augmenting BCPA with an additional source of blood flow containing hepatic factor limits the degree of intrapulmonary arteriovenous shunting and may help provide successful longer term palliation.

Reversal of intrapulmonary arteriovenous shunting detected by two-dimensional contrast-enhanced echocardiography after liver transplantation

BACKGROUND

Intrapulmonary arteriovenous shunting (IPS), occasionally associated with advanced liver disease, may reverse after liver transplantation (LTx). Two-dimensional contrast-enhanced echocardiography, a convenient noninvasive study, has never been used to demonstrate disappearance of IPS after LTx.

METHODS

For an 8-month-old girl undergoing living-related LTx, two-dimensional contrast-enhanced echocardiography was performed with the microbubble injection. The opacification of the microbubble in the left heart emerging within 3-6 beats after detection in the right heart was compared with that in the right heart.

RESULTS

Microbubble opacification in the left heart was almost the same as that in the right heart (grade 3) shortly after LTx. However, the contrast in the left heart diminished (grade 1) as the respiratory condition improved and subsequently disappeared (grade 0).

CONCLUSIONS

Two-dimensional contrast-enhanced echocardiography may be a feasible noninvasive method to evaluate the degree of IPS in the peritransplant period and observe disappearance of IPS after LTx.

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.

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.

Endothelin-1 stimulation of endothelial nitric oxide synthase in the pathogenesis of hepatopulmonary syndrome

Biliary cirrhosis in the rat triggers intrapulmonary vasodilatation and gas exchange abnormalities that characterize the hepatopulmonary syndrome. This vasodilatation correlates with increased levels of pulmonary microcirculatory endothelial nitric oxide synthase (eNOS) and hepatic and plasma endothelin-1 (ET-1). Prehepatic portal hypertension induced by portal vein ligation (PVL) does not cause similar changes, suggesting that ET-1 in cirrhosis may modulate pulmonary eNOS and vascular tone. We assessed whether ET-1 altered eNOS expression and nitric oxide production in bovine pulmonary artery endothelial cells (BPAECs) and if a 2-wk low-level intravenous ET-1 infusion in PVL animals modulated pulmonary eNOS levels, microcirculatory tone, and gas exchange. ET-1 caused a 2.5-fold increase in eNOS protein in BPAECs, inhibitable with an endothelin B receptor antagonist, and an increase in eNOS mRNA and nitrite production. ET-1 infusion in PVL animals caused increased pulmonary eNOS levels, intrapulmonary vasodilatation, and gas exchange abnormalities without increasing pulmonary arterial pressure. ET-1 produced during hepatic injury may contribute to the hepatopulmonary syndrome by modulating eNOS and inducing pulmonary microcicrulatory vasodilatation.

Prevalence of hypoxemia in 102 Japanese patients with alcoholic and nonalcoholic cirrhosis

OBJECTIVE

Liver cirrhosis is often accompanied by arterial hypoxemia in the absence of cardiopulmonary disease. The aim of this study was to investigate the relationship between various clinicopathological conditions and the hypoxemia seen in Japanese patients with liver cirrhosis.

METHODS

In 102 consecutive patients with alcoholic (N = 45) and nonalcoholic (N = 57) cirrhosis not associated with cardiopulmonary disease, we performed lung perfusion scintigraphy, contrast echocardiography, and arterial blood gas analysis and measured oxygen consumption.

RESULTS

No abnormality was seen in pulmonary blood flow in cirrhotic patients, but 38 (38%) of them had a decreased partial pressure of oxygen (PaO2). The hypoxemic patients did not show any pulmonary signs or symptoms. The hypoxemia was not associated with the Child-Pugh grade, and was observed in 32 (71%) of the 45 alcoholic patients but in only six (11%) of the 57 nonalcoholic patients (p < 0.001). Oxygen consumption was significantly higher in the alcoholic group than in the nonalcoholic group (p < 0.0001), and a high incidence of oxygen consumption was seen in all 45 (100%) of the alcoholic patients and in 34 (60%) of the nonalcoholic subjects, the difference being significant (p < 0.01). The relationship between oxygen consumption and PaO2 in the 102 cirrhotic patients showed an inverse correlation (r = -0.85, p < 0.0001). Among the alcoholic patients, the incidence of hypoxemia did not differ between the 33 smokers and the 12 nonsmokers. After 1 wk of abstinence from alcohol a significant increase (p < 0.0001) in the PaO2 was seen in 14 of 19 patients with alcoholic cirrhosis.

CONCLUSIONS

We conclude that the hypoxemia in Japanese patients with liver cirrhosis occurs mainly in drinking alcoholic patients, presumably due to an increased oxygen consumption by alcohol.

Intrapulmonary shunting in biliary atresia before and after living-related liver transplantation

BACKGROUND

Intrapulmonary shunting (IPS) is frequently observed and causes hypoxaemia in liver cirrhosis. This study investigated the prevalence, predictors of reversibility and the effect of living-related liver transplantation (LRLT) on IPS using contrast echocardiography in patients with end-stage biliary atresia.

METHODS

Fifty consecutive patients with biliary atresia were examined for IPS using contrast echocardiography before and after LRLT until IPS disappeared. The severity of IPS was classified into five grades according to the extent of contrast in the left ventricle (0, none; 1, trivial; 2, apparent; 3, complete but less than in right ventricle; 4, as dense as in right ventricle).

RESULTS

Thirty-two patients (grade 1, n = 15; grade 2, n = 7; grade 3, n = 4; grade 4, n = 6) had IPS before LRLT. Forty-four patients have survived for 9-26 months after LRLT. Among patients with grade 3 or 4 IPS (n = 8), there was a significant correlation between age at LRLT and the duration of IPS persistence after LRLT (P = 0.044).

CONCLUSION

IPS takes longer to disappear in older children than in younger ones, but always disappears eventually. LRLT is an effective treatment for biliary atresia with IPS. Presented to the 31st annual meeting of the Pacific Association of Pediatric Surgeons, Maui, Hawaii, June 1998

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.

Portal hypertension

Cirrhosis represents the end stage of any chronic liver disease. Two major syndromes result from cirrhosis: portal hypertension and hepatic insufficiency. Additionally, vasodilatation and the hyperdynamic circulation are hemodynamic abnormalities typical of cirrhosis and portal hypertension. Complications of cirrhosis occur as a consequence of a combination of these factors. Gastroesophageal varices result almost solely from portal hypertension, although the hyperdynamic circulation contributes to variceal growth and hemorrhage. Ascites results from sinusoidal hypertension and sodium retention, which is, in turn, secondary to vasodilatation and activation of neurohumoral systems. Hyponatremia and the hepatorenal syndrome result from water retention and renal vasoconstriction, respectively, both of which are also consequences of peripheral vasodilatation. Vasodilatation that occurs in the pulmonary circulation leads to the hepatopulmonary syndrome. Another complication of cirrhosis, portosystemic encephalopathy, is a consequence of both portal hypertension (shunting of blood through portosystemic collaterals) and hepatic insufficiency. This paper reviews the recent advances in the pathophysiology and management of the complications of cirrhosis and portal hypertension.

Localizing intrapulmonary shunt in hepatopulmonary syndrome by transesophageal echocardiography

Transesophageal echocardiography combining with peripheral injection of agitated saline solution is a useful diagnostic tool to detect the intrapulmonary shunt. We performed transesophageal contrast echocardiography in a case of hepatopulmonary syndrome with normal pulmonary angiography to define the intrapulmonary right-to-left shunt bilaterally.

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.

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.

Analysis of intrapulmonary right to left shunt in the hepatopulmonary syndrome

BACKGROUND/AIMS

Severe hypoxaemia in patients with chronic liver disease in the absence of intrinsic lung disease, the hepatopulmonary syndrome, is associated with pulmonary vascular dilatation and may be an indication for liver transplantation. Divergence between two methods of measuring right to left shunt (radiolabelled albumin macroaggregates and 100% oxygen breathing) has been described, but the mechanism and reason for the inter-patient variability for this shunt difference are not well understood.

METHODS

Eight hepatopulmonary syndrome patients were studied, with characteristic pulmonary diffusion abnormalities (carbon monoxide transfer factor 41+/-5 (mean+/-SE)% predicted) and significant decreases in arterial oxygen saturation (%) on standing vs. supine (-10%+/-3) and on exercise vs. rest (-15%+/-2). All had hypoxaemia at rest (arterial oxygen tension 8.2+/-0.6 kPa), partially corrected by breathing 100% oxygen (48.2+/-8.8 kPa). Pulmonary angiography was performed and right to left shunt measured by two independent methods: (a) 100% oxygen breathing and (b) i.v. injection of radiolabelled microspheres.

RESULTS

Measurement of right to left shunt with 99mTc-labelled albumin macroaggregates confirmed significant intrapulmonary microvascular dilatation, i.e. an "anatomical" shunt equalling 32+/-4% of cardiac output. Shunt measurements made simultaneously by the classical 100% oxygen technique were significantly smaller (19+/-3%, p=0.01). For individuals, the difference between the 99mTc-albumin macroaggregate shunt and the 100% oxygen shunt ranged from 2% to 30% absolute, convergence suggesting larger shunt channels (pure anatomical shunt) and divergence representing a combination of anatomical shunt and alveolar-capillary diffusion limitation (smaller microvascular channels).

CONCLUSIONS

Hypoxaemia in the hepatopulmonary syndrome may be due functionally either to right to left shunting or to diffusion limitation, depending upon the degree of dilatation of the pulmonary microvessels.

Intrapulmonary shunting in primary pulmonary hypertension: an observation in two patients treated with epoprostenol sodium

Continuous intravenous infusion of epoprostenol sodium in selected patients with primary pulmonary hypertension improves symptoms and survival. This report describes two patients with primary pulmonary hypertension treated with epoprostenol in whom intrapulmonary shunting and severe hypoxemia occurred. Intrapulmonary shunting was confirmed by contrast echocardiography showing delayed appearance of bubbles in the left cardiac chambers after peripheral venous injection of agitated saline solution.

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.

Complications of cirrhosis. Why they occur and what to do about them

Cirrhosis is a chronic disease of the liver in which dense bands of fibrosis enclose regenerative hepatocellular nodules. Clinical and radiologic features of advanced liver disease provide presumptive evidence for the presence of cirrhosis. Major complications are related to the increased hepatic resistance, increased sodium and water retention, and hyperdynamic changes of the circulatory system. Patient management should consist of appropriate prophylaxis for the life-threatening complications of variceal bleeding and spontaneous bacterial peritonitis and treatment of other complications as signs and symptoms develop.

Combined Interatrial and Intrapulmonary Shunting in Orthodeoxia Detected by Transesophageal Echocardiography

Contrast transesophageal echocardiography was found useful in diagnosing combined interatrial and intrapulmonary right-to-left shunts in a patient presenting with orthodeoxia. This was done by separately examining the pulmonary veins and the interatrial septum during intravenous normal saline injections.

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.

Comparison of transesophageal and transthoracic contrast echocardiography for detection of an intrapulmonary shunt in liver disease

STUDY OBJECTIVES

Contrast transthoracic echocardiography (TTE) is currently used to identify intrapulmonary shunt (IPS) in patients with end-stage liver disease. The aim of this study was to compare the use of contrast TTE and transesophageal echocardiography (TEE) in detecting IPS.

DESIGN

Thirty-seven consecutive outpatients with severe liver disease awaiting liver transplantation underwent contrast TEE and TTE. The IPS was assessed semiquantitatively in four grades with TEE and as positive or negative with TTE.

SETTING

ICU.

INTERVENTIONS

Patients underwent contrast TEE after pharyngeal anesthesia alone followed by contrast TTE. Contrast echocardiography was performed with a modified fluid gelatin solution.

RESULTS

Overall detection rate of an IPS was 51% with TEE and 32% with TTE (p < 0.001). Four patients had an IPS detected with TEE but not with TTE. Quality of imaging was poor in 22% with TTE and 0% with TEE (p < 0.001). A PaO2 < 80 mm Hg or a dyspnea was associated with an IPS in 56% and 50% of patients with TEE and in 33% and 25% with TTE, respectively.

CONCLUSION

Contrast-enhanced TEE is superior to TTE for detecting an IPS in patients with severe liver disease awaiting liver transplantation. The use of gelatin contrast solution allows an early detection of IPS. Because of the high sensitivity of TEE, all patients suspected of hepatopulmonary syndrome should undergo TEE in search of an IPS if TTE is normal.

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.

Scenario number one: hepatopulmonary syndrome

HPS is an increasingly recognized clinical entity resulting from intrapulmonary vasodilatation in patients with liver disease and/or portal hypertension. The pathogenesis of alterations in the pulmonary vascular bed in affected patients is poorly understood and the subject of ongoing investigation. The differential diagnosis of pulmonary symptoms and gas-exchange abnormalities in patients with liver disease being evaluated for transplantation is broad and should be focused on differentiating pulmonary causes that significantly increase the risk for transplantation from HPS where transplantation has emerged as a useful treatment. Specific contraindications to transplantation in patients with HPS have not been identified, though unique postoperative complications have been observed and may be treatable during the frequently prolonged resolution of intrapulmonary vasodilatation. The development of a database of information on patients with HPS undergoing transplantation will provide insight into potential contraindications, prognostic features, and postoperative complications unique to these patients.