Hepatopulmonary Syndrome: A Brief Review

Hepatopulmonary syndrome (HPS) is a pulmonary complication of liver disease characterized by arterial hypoxemia. Mechanisms related to this event are diffusion-perfusion flaw, ventilation-perfusion (V/Q) mismatch, and direct arteriovenous shunts. Diagnosis of HPS is based on the presence of liver disease or portal hypertension, increased alveolar-arterial (A-a) PO2, and intrapulmonary vascular dilatations (IPVD). Lung transplantation (LT) remains the most effective therapy for HPS. In spite of its poor prognosis, we could improve the quality of life and survival rate of patients.

[The hepatopulmonary syndrome]

The hepatopulmonary syndrome (HPS) - a complication of liver disease - seems to be underdiagnosed, probably because of decreased awareness. HPS consists of the triade liver disease, intrapulmonary vascular dilatation and as a consequence arterial hypoxaemia. No medical therapy has proven effective perhaps with the exception of garlic, which has been effective in one controlled clinical trial. However, liver transplantation seems to improve HPS in most cases. Liver patients with unexplained hypoxaemia should be investigated for HPS.

The Art and Science of Diagnosing and Treating Lung and Heart Disease Secondary to Liver Disease

Patients with chronic liver disease are at risk of extrahepatic complications related to cirrhosis and portal hypertension, as well as organ-specific complications of certain liver diseases. These complications can compromise quality of life, while also increasing morbidity and mortality before and after liver transplantation. Patients with chronic liver disease are at risk for pulmonary complications of hepatopulmonary syndrome and portopulmonary syndrome; the cardiac complication fall under the general concept of cirrhotic cardiomyopathy, which can affect systolic and diastolic function, as well as cardiac conduction. In addition, patients with certain diseases are at risk of lung and/or cardiac complications that are specific to the primary disease (ie, emphysema in α-1-antitrypsin deficiency) or occur with increased incidence in certain conditions (ie, ischemic heart disease associated with nonalcoholic steatohepatitis). This article focuses on the epidemiology, clinical presentation, pathogenesis, treatment options, and role of transplantation for lung and heart diseases secondary to liver disease, while also highlighting select liver diseases that directly affect the lungs and heart.

Clinical characteristics, predictors, and survival among patients with hepatopulmonary syndrome

BACKGROUND

Hepatopulmonary syndrome (HPS) is a complication of advanced liver disease. The impact of HPS on survival is not clearly understood.

MATERIAL AND METHODS

A prospective study was carried out at Department of Medicine, King Edward Medical University Lahore from June 2011 to May 2012. Patients with cirrhosis of liver were evaluated for presence of HPS with arterial blood gas analysis and saline bubble echocardiography. All patients were followed for 6 months for complications and mortality. Cox regression analysis was done to evaluate role of HPS on patient survival.

RESULTS

110 patients were included in the study. Twenty-nine patients (26%) had HPS. MELD score was significantly higher (p < 0.01) in patients with HPS (18.93 ± 3.51) as compared to that in patients without HPS (13.52 ± 3.3). Twenty two (75.9%) patients of Child class C, 5 (17.2%) patients of Child class B and 2 (6.9%) patients of Child class A had HPS (P 0.03). The clinical variables associated with presence of HPS were spider nevi, digital clubbing, dyspnea, and platypnea. HPS significantly increased mortality during six month follow up period (HR: 2.47, 95% CI: 1.10- 5.55). Child-Pugh and MELD scores were also associated with increased mortality. HPS was no longer associated with mortality when adjustment was done for age, gender, Child-Pugh, and MELD scores (HR: 0.44, 95% CI: 0.14-1.41). Both the Child-Pugh and MELD scores remained significantly associated with mortality in the multivariate survival analysis.

CONCLUSIONS

HPS indicates advanced liver disease. HPS does not affect mortality when adjusted for severity of cirrhosis.

Hepatopulmonary Syndrome, Severe Cyanosis and Marfanoid Habitus

We report the case of a 17-year-old male with Marfanoid habitus who presented with deep cyanosis, haematemesis, dyspnoea and platypnoea. He had oesophageal varices, indicating portal hypertension, with mildly deranged liver function. His arterial blood gas (ABG) revealed hypoxia and orthodeoxia. Contrast-enhanced echocardiography with agitated saline and a 99m Technetium macro-aggregated albumin perfusion lung scan confirmed intrapulmonary shunting. Pulmonary angiogram showed multiple, small diffuse pulmonary arteriovenous fistulae scattered all over the lungs and predominantly in the bases of the lungs. Based on these results and the clinical background a diagnosis of hepatopulmonary syndrome with Marfanoid habitus was made. Patient was treated conservatively as he was not prepared for liver transplantation.

Portopulmonary hypertension and hepatopulmonary syndrome

Portopulmonary hypertension (POPH) and hepatopulmonary syndrome (HPS) are two frequent complications of liver disease, with prevalence among liver transplant candidates of 6% and 10%, respectively. Both conditions result from a lack of hepatic clearance of vasoactive substances produced in the splanchnic territory. Subsequently, these substances cause mainly pulmonary vascular remodeling and some degree of vasoconstriction in POPH with resulting elevated pulmonary pressure and right ventricular dysfunction. In HPS the vasoactive mediators cause intrapulmonary shunts with hypoxemia. Medical treatment is disappointing overall. Whereas liver transplantation (LT) results in the disappearance of HPS within six to twelve months, its effect on POPH is highly unpredictable. Modern strategies in managing HPS and POPH rely on a thorough screening and grading of the disease’s severity, in order to tailor the appropriate therapy and select only the patients who will benefit from LT. The anesthesiologist plays a central role in managing these high-risk patients. Indeed, the important hemodynamic and respiratory modifications of the perioperative period must be avoided through continuation of the preoperatively initiated drugs, appropriate intraoperative monitoring and proper hemodynamic and respiratory therapies.

Impact of the hepatopulmonary syndrome MELD exception policy on outcomes of patients after liver transplantation: an analysis of the UNOS database

BACKGROUND & AIMS

Patients with hepatopulmonary syndrome (HPS) are prioritized for liver transplantation (given exception points) due to their high pre- and post-transplantation mortality. However, few studies have evaluated the outcomes of these patients.

METHODS

We performed a retrospective cohort study using data submitted to the United Network for Organ Sharing in a study of the effects of room-air oxygenation on pre- and post-transplantation outcomes of patients with HPS. We identified thresholds associated with post-transplantation survival using cubic spline analysis and compared overall survival times of patients with and without HPS.

RESULTS

From 2002 through 2012, nine hundred and seventy-three patients on the liver transplant waitlist received HPS exception points. There was no association between oxygenation and waitlist mortality among patients with HPS exception points. Transplant recipients with more severe hypoxemia had increased risk of death after liver transplantation. Rates of 3-year unadjusted post-transplantation survival were 84% for patients with PaO2 of 44.1-54.0 mm Hg vs 68% for those with PaO2 ≤ 44.0 mm Hg. In multivariable Cox models, transplant recipients with an initial room-air PaO2 ≤ 44.0 mm Hg had significant increases in post-transplantation mortality (hazard ratio = 1.58; 95% confidence interval [CI]: 1.15-2.18) compared with those with a PaO2 of 44.1-54.0 mm Hg. Overall mortality was significantly lower among waitlist candidates with HPS exception points than those without (hazard ratio = 0.82; 95% CI: 0.70-0.96), possibly because patients with HPS have a reduced risk of pre-transplantation mortality and similar rate of post-transplantation survival.

CONCLUSIONS

Although there was no association between pre-transplantation oxygenation and waitlist survival in patients with HPS Model for End-Stage Liver Disease exception points, a pre-transplantation room-air PaO2 ≤ 44.0 mm Hg was associated with increased post-transplantation mortality. HPS Model for End-Stage Liver Disease exception patients had lower overall mortality compared with others awaiting liver transplantation, suggesting that the appropriateness of the HPS exception policy should be reassessed.

[Hepatopulmonary syndrome causing severe hypoxaemia]

Dyspnoea is a common complaint in patients with chronic liver disease. Hepatopulmonary syndrome (HPS) is an important cause to be aware of in the setting of liver disease, dyspnoea and hypoxaemia. HPS causes microvascular dilatation, angiogenesis and arteriovenous bypassing. The patients suffer from hypoxaemia in upright position and even during minimal psychical activity. Contrast echocardiography, using micro-bubbles as the contrast, is required to establish the diagnosis. No medical therapy is available, only liver transplantation can cure the disease.

Cirrhosis and hepatopulmonary syndrome

Hepatopulmonary syndrome (HPS) is characterized as a triad: liver disease, intrapulmonary vascular dilatation and arterial hypoxemia. HPS is reported to be present in 4% to 32% of adult patients with end-stage liver disease and in 9%-20% of children. The pathogenesis of HPS has not been clearly identified. Portal hypertension causes impairment in the perfusion of the bowel and increases the enteral translocation of Gram (-) bacteria and endotoxins. This stimulates the release of vasoactive mediators, such as tumor necrosis factor-alpha, heme oxygenase-derived carbon monoxide and nitric oxide. Genetic alterations have not been associated with this syndrome yet; however, cytokines and chemokines have been suggested to play a role. Recently, it was reported that cumulated monocytes lead to the activation of vascular endothelial growth factor-dependent signaling pathways and pulmonary angiogenesis, which plays an important role in HPS pathogenesis. At present, the most effective and only radical treatment is a liver transplant (LT). Cirrhotic patients who are on the waiting list for an LT have a shorter survival period if they develop HPS. Therefore, it is suggested that all cirrhotic cases should be followed closely for HPS and they should have priority in the waiting list.

Pulse oximetry is insufficient for timely diagnosis of hepatopulmonary syndrome in children with liver cirrhosis

OBJECTIVE

To prospectively investigate the prevalence of hepatopulmonary syndrome (HPS), the importance of pulse oximetry in diagnosing HPS, and the longitudinal course after liver transplantation in children with cirrhosis referred for liver transplantation.

STUDY DESIGN

Fifty-six patients aged 1-17 years (mean age, 4.6 ± 5.0 years) with liver cirrhosis were screened for HPS by hyperemic capillary blood gas (CBG) analysis and contrast-enhanced transthoracic echocardiography. Eleven patients were excluded owing to conditions that can produce cardiopulmonary dysfunction, including 5 with cystic fibrosis, 1 with pulmonary arterial hypertension, and 5 with an intracardial shunt. HPS was classified in accordance with the European Respiratory Society Task Force criteria on pulmonary-hepatic disorders. Patient groups were compared for biochemical and clinical characteristics.

RESULTS

Eighteen children (40%) with cirrhosis were intrapulmonary vasodilatation (IPVD)-positive and had a pulse oximetry oxygen saturation level >98%. Two of these patients (11%) exhibited moderate HPS with an elevated alveolar arterial oxygen gradient >15 mm Hg and PaO2 <70 mm Hg; they died before undergoing liver transplantation. The sensitivity and specificity of CBG analysis for detecting elevated alveolar arterial oxygen gradient in children with IPVD was 94% and 53%, respectively. HPS was associated with late hepatoportoenterostomy (P < .04). Liver transplantation led to resolution of HPS in all patients.

CONCLUSION

IPVD is frequent in children with liver cirrhosis (40%). Pulse oximetry is insufficient for timely HPS diagnosis. Pathological CBG analysis data indicate IPVD in the majority of cases, but are imprecise in children aged <2 years. Contrast-enhanced transthoracic echocardiography and CBG analysis are recommended for evaluation of HPS in children with cirrhosis, regardless of liver synthesis capacity and clinical chemistry data.

[Hepatopulmonary syndrome]

Hepatopulmonary syndrome (HPS) is characterized by the triad of liver disease, intrapulmonary vascular dilatation and arterial deoxygenation. Mediating factors are tumor necrosis factor a, endothelin 1 and nitric oxide. Typical symptom is an increase in dyspnea while in standing position, orthodeoxia. In orthodeoxia hypoxemia accentuates while the partial pressure of oxygen in arterial blood decreases by 5% or more. The blood flow distribution to the lungs is changed as the pulmonary vascular tone is altered. Diagnosis is based on the evidence of liver disease, hypoxemia and pulmonary vascular shunt detected by the so-called bubble test. Liver transplantation is currently the only efficient therapeutic option.

Paradoxical arterial hypoxemia in a left-to-right shunt congenital heart disease

The hepatopulmonary syndrome is a rare complication of different types of chronic hepatic diseases with associated portal venous hypertension, resulting in pulmonary vascular dilatation, predominantly in the lower lung fields, and leading to ventilation-perfusion mismatch, arterial hypoxemia and a poor prognosis. We present the case of 42-year-old male patient with an anomalous drainage of the right superior pulmonary vein into the azygos vein and a portal vein cavernomatosis with associated portal venous hypertension who presented severe oxygen desaturation, during exercise, in the context of a hepatopulmonary syndrome.

Respiratory system involvement in chronic liver diseases

Liver diseases are often associated with respiratory complications. They may manifest as pleural effusion, interstitial lung disease, as well as various combinations of symptoms affecting the pulmonary vasculature. The duration and severity of liver disease is not always reflected by the degree of lung function impairment. On the other hand, progressive damage to the lungs significantly worsens prognosis in the course of severe liver disease. The diagnosis is difficult and often requires multidisciplinary cooperation. The effects of pharmacological treatment are not always satisfactory. In numerous cases, liver transplantation proves to be the best option.

Screening of hepatopulmonary syndrome (HPS) with CEUS and pulse-oximetry in liver cirrhosis patients eligible for liver transplant

BACKGROUND AND AIM

The prevalence of hepatopulmonary syndrome (HPS) in the setting of cirrhosis ranges between 4%-47%. We aimed to detect a correlation between heart and lungs findings on contrast-enhanced ultrasound (CEUS)and pulse-oximetry, in order to early detect HPS and thus to improve patients referral to orthotopic liver transplantation(OLT).

METHODS

We considered at risk for HPS all patients with delayed left ventricle (LV) enhancement of the contrast agent,at least 3 systolic beats after it appears in the right ventricle(RV). We correlated CEUS results with pulse-oximetry findings,considering to have a positive HPS diagnosis in all patients with both CEUS findings and SaO2 95%.

RESULTS

From 186 patients diagnosed with liver cirrhosis, 56 patients (30.10%) had delayed LV enhancement of the contrast agent. Pulse-oximetry showed alterations, such as SaO2 95%and PaO2 70 mmHg in 62 patients (33.33%). Pearson index showed a good correlation between lung and heart CEUS findings and pulse-oximetry (r=0.99) in HPS diagnosis. CONCLUSIONS. Two non-invasive, simple and rapid methods such as CEUS and pulse-oximetry can easily diagnose HPS, a highly fatal complication of liver cirrhosis, and can also guide the future treatment by speeding up OLT recommendations.

[Hepatopulmonary syndrome: a complication of type 1 Gaucher disease]

Gaucher's disease is a not exceptional lysosomial disease in Tunisia. Type 1 is by far the most common one. Pulmonary involvement is considered to be rare in type 1 Gaucher's disease. Pulmonary hypertension, infiltration of the lungs with Gaucher cells, and severe hypoxemia due to intrapulmonary arterial-venous shunts, have been described in case reports and small case series. We reported the case of hepatopulmonary syndrome in a 14-year-old boy with type 1 Gaucher disease. The diagnosis of Gaucher disease was established, at 2 years age, by enzyme assay of leucocyte β-glucosidase. The patient presented dyspnoea, digital clubbing and cyanosis of the lips. The arterial blood gas found severe hypoxaemia with PaO(2) at 56.9 mmHg. The diagnosis of hepatopulmonary syndrome, in our patient, was confirmed by demonstration of the intrapulmonary shunting using contrast-enhanced echocardiography and the technetium-99m-labeled macroaggregated albumin. The patient was treated by symptomatic measure, long term oxygen therapy because the insufficiency of the enzyme replacement therapy. Screening for hypoxemia in children with liver disease should be considered.

Pulmonary complications of cirrhosis

Pulmonary vascular complications of liver disease comprise two distinct clinical entities: hepatopulmonary syndrome (HPS-microvascular dilatation and angiogenesis) and portopulmonary hypertension (POPH-vasoconstriction and remodeling in resistance vessels). These complications occur in similar pathophysiologic environments and may share pathogenic mechanisms. HPS is found in 15% to 30% of patients with cirrhosis and its presence increases mortality and the risks of liver transplantation, particularly when hypoxemia is present. Contrast echocardiography and arterial blood gas analysis are required to establish the diagnosis. No medical therapies are available, although liver transplantation is effective in reversing the syndrome. POPH is found in 4% to 8% of patients undergoing liver transplantation evaluation, and the presence of moderate to severe disease significantly increases perioperative transplant mortality. Transthoracic echocardiography is recommended for screening and right-heart catheterization is required to establish the diagnosis. Medical therapies are increasingly effective in improving pulmonary vascular hemodynamics in POPH and may result in better perioperative outcomes.

Hepatopulmonary syndrome: prevalence and predictors in Egyptian cirrhotic patients

BACKGROUND

The reported prevalence of hepatopulmonary syndrome (HPS) in cirrhotic patients is heterogeneous. Although the prevalence of chronic liver diseases is high in Egypt, however, scanty data is available about HPS.

AIM

To assess the frequency of HPS and factors predictive of diagnosis of HPS in Egyptian patients with liver cirrhosis.

METHODS

Fifty cirrhotic patients were evaluated for the presence of HPS. Orthodeoxia was measured by arterial blood gas test. The patients positive for diagnostic criteria of HPS (the presence of A-a O2 > or = 15 mmHg and pulmonary vascular dilatation assessed by contrast enhanced echocardiography) were defined as clinical HPS cases and those manifesting with intrapulmonary arterial dilation but no other criteria were defined as subclinical HPS cases.

RESULTS

Subclinical HPS and clinical HPS was observed in 10 (20%) and 17 (34%) of the patients, respectively. The presence of HPS was significantly associated with severity of liver disease assessed by the Child-Pugh score (CP) or MELD score. Portal vein diameter (mm) (OR 3.3; 95% C.I 1.3-8.2; p=0.01) was the only independent predictor for HPS; the specificity of orthodeoxia for diagnosis of HPS was 100%.

CONCLUSIONS

HPS and intrapulmonary vein dilation are relatively frequent in patients with liver cirrhosis and occur in 34% and 20% of cirrhosis patients, respectively. They are associated with disease severity according to the MELD and CP score. Alveolar arterial oxygen gradient is the most valuable negative and positive diagnostic predictor for presence of HPS in cirrhotic patients.

[Pulmonary affection in advanced liver disease - hepatepulonary syndrome and portopulmonary hypertension]

Patients suffering from severe chronic liver disease, in particular cirrhosis, are at risk for pulmonary complications. The leading clinical symptom is shortness of breath, which can accompany the actual disease as indirect effect because of anemia, faint muscles or ascites. On the other hand, dyspnea can have multiple additive causes in case of accompanying cardial or pulmonary disease. The hepatopulmonary syndrome (HPS) and the portopulmonary hypertension (PoPH) belong to the most relevant pulmonary complications in liver cirrhosis. HPS appears to be more common than PoPH and the presence of either entity increases morbidity and mortality in patients with liver disease. The two diseases have to be strictly distinguished, as they have opposed histological and pathophysiological origin. While the HPS is a dilatative pulmonary- vascular disease, the PoPH is a constrictive or obliterative pulmonary-vascular disease in the context of a liver disease or a portal hypertension. Therefore, these diseases are separate entities also when it comes to diagnostics and therapy.

[Hepato-pulmonary syndrome]

The hepato-pulmonary syndrome (HPS) is a rare complication of liver cirrhosis, with poor outcome; the term includes liver disease, increased alveolo-arterial gradient and intrapulmonary vascular dilations, described by Fluckiger, Kennedy and Knudson. HPS impairs survival in cirrhotic patients and the posttransplant outcome is altered in correlation with severity of HPS. Combined determination of SaO2 in clino- and orthostatic position by a pulsoximeter is a simple test for HPS identification in patients with chronic liver disease or non-cirrhotic portal hypertension.

[Hepatopulmonary syndrome: case report and literature review]

Hepatopulmonary syndrome is an important complication of chronic liver disease occurring in 16 24% of patients. It is characterized by an increase in alveolar -capillary gradient, with or without hypoxemia, due to intrapulmonary vasodilatation. The course of the disease is progressive and associated with increased morbidity and mortality. There is no effective medical treatment and liver transplant is a priority. To exemplify the authors present the case of a 39 year -old male patient sent to the Pulmonology outpatient clinic and presenting with secondary polycythemia and progressive exertional dyspnoea. Clinical investigation identified a hepatopulmonary syndrome.

Physiopathological, clinical and therapeutic aspects of hepatopulmonary syndrome

Patients with cirrhosis or portal hypertension may develop hepatopulmonary syndrome (HPS) and portopulmonary hypertension (PPHT). HPS occurs in 25% of the subjects with chronic hepatopathy waiting for a liver transplantation. HPS is characterized by chronic hepatopathy and/or portal hypertension, increased P(A-a)O2 gradient (more than 20 mmHg) with hypoxemia and intrapulmonary vascular dilatations without a primary cardiovascular disease. Hypoxiemia is due to intrapulmonary arteriovenous shunts and to dilatation of microvessels in basal parts of the lung and of pleural vessels. In patients with cirrhosis an impaired cardiovascular function is frequent, often in a subclinical phase of the disease. Left ventricular systolic and diastolic dysfunction may develop a chronic hepatopathy and the relation between right ventricular and liver failure has been studied. During cirrhosis characteristic alterations of systemic hemodynamic can cause the hyperdynamic circulatory syndrome. Contrast enhanced 2D ECHO cardiography is the preferred screening test for intrapulmonary arteriovenous shunts. The aim of HPS therapy is to contrast intrapulmonary vasodilatation, increased portal flux and hyperdynamic syndrome. New therapeutical agents are fosfodiesterase inhibitors, ET-1 receptor antagonists and selective NOS inhibitors. However, medical treatment is not much effective in HPS and liver transplantation is considered the only therapeutical chance.

Pulmonary vascular complications in asymptomatic children with portal hypertension

OBJECTIVES

: To determine the prevalence of portopulmonary hypertension, hepatopulmonary syndrome (HPS), and intrapulmonary vascular shunting (IPVS) in children with clinically stable portal hypertension and to assess the value of vasoactive peptide levels, biochemical tests and clinical signs or symptoms to predict these conditions.

PATIENTS AND METHODS

: A prospective, cross-sectional analysis was conducted on 33 children, ages 4 to 17 years, with stable cirrhosis (n = 28) or extrahepatic portal hypertension (n = 5). The children were screened for IPVS and hypoxia with contrast-enhanced echocardiography (cECHO) and pulse oximetry, and screened for pulmonary hypertension with Doppler echocardiography. Chemistries, radiographs, physical examinations, and levels of vasoactive peptides were compared between subjects with IPVS and those with normal cECHO.

RESULTS

: No subject had pulmonary hypertension. Six (19%) had IPVS, all of which had intrahepatic causes of portal hypertension, and 1 of whom had HPS. Compared with subjects with normal cECHO, those with IPVS had biochemical evidence of more advanced liver disease and higher b-type natriuretic peptide levels.

CONCLUSIONS

: Prevalence of portopulmonary hypertension and HPS appear to be rare in clinically stable children with portal hypertension. Intrapulmonary vascular shunting was present in 19% of these patients. A novel finding of this study is the elevation of b-type natriuretic peptide in children with IPVS.