Hepatopulmonary Syndrome and Portopulmonary Hypertension: Implications for Liver Transplantation

Hepatopulmonary syndrome is associated with low sphingosine-1-phosphate levels and can be ameliorated by the functional agonist fingolimod

BACKGROUND & AIMS

Hepatopulmonary syndrome (HPS) is characterised by a defect in arterial oxygenation induced by pulmonary vascular dilatation in patients with liver disease. Fingolimod, a sphingosine-1-phosphate (S1P) receptor modulator, suppresses vasodilation by reducing nitric oxide (NO) production. We investigated the role of S1P in patients with HPS and the role of fingolimod as a therapeutic option in an experimental model of HPS.

METHODS

Patients with cirrhosis with HPS (n = 44) and without HPS (n = 89) and 25 healthy controls were studied. Plasma levels of S1P, NO, and markers of systemic inflammation were studied. In a murine model of common bile duct ligation (CBDL), variations in pulmonary vasculature, arterial oxygenation, liver fibrosis, and inflammation were estimated before and after administration of S1P and fingolimod.

RESULTS

Log of plasma S1P levels was significantly lower in patients with HPS than in those without HPS (3.1 ± 1.4 vs. 4.6 ± 0.2; p <0.001) and more so in severe intrapulmonary shunting than in mild and moderate intrapulmonary shunting (p <0.001). Plasma tumour necrosis factor-α (76.5 [30.3-91.6] vs. 52.9 [25.2-82.8]; p = 0.02) and NO (152.9 ± 41.2 vs. 79.2 ± 29.2; p = 0.001) levels were higher in patients with HPS than in those without HPS. An increase in Th17 (p <0.001) and T regulatory cells (p <0.001) was observed; the latter inversely correlated with plasma S1P levels. In the CBDL HPS model, fingolimod restored pulmonary vascular injury by increasing the arterial blood gas exchange and reducing systemic and pulmonary inflammation, resulting in improved survival (p = 0.02). Compared with vehicle treatment, fingolimod reduced portal pressure (p <0.05) and hepatic fibrosis and improved hepatocyte proliferation. It also induced apoptotic death in hepatic stellate cells and reduced collagen formation.

CONCLUSIONS

Plasma S1P levels are low in patients with HPS and even more so in severe cases. Fingolimod, by improving pulmonary vascular tone and oxygenation, improves survival in a murine CBDL HPS model.

IMPACT AND IMPLICATIONS

A low level of plasma sphingosine-1-phosphate (S1P) is associated with severe pulmonary vascular shunting, and hence, it can serve as a marker of disease severity in patients with hepatopulmonary syndrome (HPS). Fingolimod, a functional agonist of S1P, reduces hepatic inflammation, improves vascular tone, and thus retards the progression of fibrosis in a preclinical animal model of HPS. Fingolimod is being proposed as a potential novel therapy for management of patients with HPS.

Vascular Extracellular Vesicles Indicate Severe Hepatopulmonary Syndrome in Cirrhosis

Background: Hepatopulmonary syndrome (HPS) is a pulmonary vasculature complication in the setting of liver disease that is characterized by pathological vasodilation resulting in arterial oxygenation defects. We investigated the role of extracellular vesicles (EV) in cirrhosis patients with HPS, as well as the functional effect of EV administration in a common bile duct ligation (CBDL) HPS mouse model. Methods: A total of 113 cirrhosis patients were studied: 42 (Gr. A) with HPS and 71 (Gr. B) without HPS, as well as 22 healthy controls. Plasma levels of EV associated with endothelial cells, epithelial cells, and hepatocytes were measured. The cytokine cargoes were estimated using ELISA. The effect of EV administered intranasally in the CBDL mouse model was investigated for its functional effect in vascular remodeling and inflammation. Results: We found endothelial cells (EC) associated EV (EC-EV) were elevated in cirrhosis patients with and without HPS (p < 0.001) than controls. EC-EV levels were higher in HPS patients (p = 0.004) than in those without HPS. The epithelial cell EVs were significantly high in cirrhosis patients than controls (p < 0.001) but no changes found in patients with HPS than without. There was a progressive increase in EC-EV levels from mild to severe intrapulmonary shunting in HPS patients (p = 0.02 mild vs. severe), and we were able to predict severe HPS with an AUROC of 0.85; p < 0.001. An inverse correlation of EC-EVs was found with hemoglobin (r = −0.24; p = 0.031) and PaO2 (r = 0.690; p = 0.01) and a direct correlation with MELD (r = 0.32; p = 0.014). Further, both TNF-α (p = 0.001) and IL-1β (p = 0.021) as cargo levels were significantly elevated inside the EVs of HPS patients than without HPS. Interestingly, upon administration of intranasal EVs, there was a significant decrease in Evans blue accumulation and lung wet–dry ratio (p = 0.042; 0.038). A significant reduction was also noticed in inflammation and cholestasis. Conclusion: High levels of plasma EC-EV levels were found in patients with HPS with elevated pro-inflammatory cytokine cargoes. EC-EVs were indicative of severe HPS condition. In the CBDL HPS model, we were able to prove the beneficial effects of improving vascular tone, inflammation, and liver pathogenesis.

Value of Contrast Transesophageal Echocardiography in the Detection of Intrapulmonary Vascular Dilatations in Hepatosplenic Schistosomiasis

Background

Hepatopulmonary syndrome (HPS), found in cirrhotic patients, has been little studied in hepatosplenic schistosomiasis (HSS) and includes the occurrence of intrapulmonary vascular dilatations (IPVD). Contrast transesophageal echocardiography (cTEE) with microbubbles is more sensitive than contrast transthoracic echocardiography (cTTE) with microbubbles in the detection of IPVD in cirrhosis.

Objective

To assess the performance of the cTEE, compared with that of cTTE, in detecting IPVD for the diagnosis of HPS in patients with HSS.

Methods

cTEE and cTTE for investigation of IPVD and laboratory tests were performed in 22 patients with HSS. Agitated saline solution was injected in peripheral vein during the cTEE and cTTE procedures. Late appearance of the microbubbles in the left chambers indicated the presence of IPVD. Results of the two methods were compared by the Student’s t-test and the chi-square test (p < 0.05).

Results

cTEE was performed in all patients without complications. Three patients were excluded due to the presence of patent foramen ovale (PFO). The presence of IPVD was confirmed in 13 (68%) of 19 patients according to the cTEE and in only six (32%, p < 0.01) according to the cTTE. No significant differences in clinical or laboratory data were found between the groups with and without IPVD, including the alveolar-arterial gradient. The diagnosis of HPS (presence of IPVD with changes in the arterial blood gas analysis) was made in five patients by the cTEE and in only one by the cTTE (p = 0.09).

Conclusion

In HSS patients, cTEE was safe and superior to cTTE in detecting IPVD and allowed the exclusion of PFO.

Pulse Oximetry Is Insensitive for Detection of Hepatopulmonary Syndrome in Patients Evaluated for Liver Transplantation

Screening for hepatopulmonary syndrome (HPS) using pulse oximetry is recommended in liver transplant (LT) candidates because mortality is increased, independently of the severity of the oxygenation defect. LT exception points may be afforded to those with HPS and severe hypoxemia. We assessed the screening characteristics of pulse oximetry for HPS. The Pulmonary Vascular Complications of Liver Disease 2 study is a multicenter, prospective cohort study of adults undergoing their first LT evaluation. Patients underwent protocolized assessment of oxygen saturation by pulse oximetry (SpO2 ), arterial blood gas, spirometry, and contrast-enhanced echocardiography (CE). HPS was defined as an alveolar-arterial gradient ≥15 mm Hg (≥20 mm Hg if age >64 years), intrapulmonary vascular dilatation on CE, and absence of lung disease. The study sample included 363 patients. Of these, 75 (20.7%; 95% confidence interval [CI], 16.6%-25.2%) met the criteria for HPS. The area under the receiver operating characteristic curve (or c-statistic) for SpO2 in discriminating HPS was 0.59 (95% CI, 0.51-0.66). An SpO2 <96%, recommended by practice guidelines as a threshold to require further testing, had low sensitivity (28%; 95% CI, 18%-28%). The c-statistic of SpO2 in discriminating HPS with a partial pressure of oxygen (PaO2 ) <60 mm Hg (eligible for LT exception points) was 0.76 (95% CI, 0.46-1.00). An SpO2 cutoff of <96% had higher sensitivity for detecting HPS with PaO2 <60 mm Hg (71%; 95% CI, 38%-100%) but was still inadequate. Conclusion: Pulse oximetry is not sufficiently sensitive to screen for HPS in LT candidates. Arterial blood gas and CE are required in LT candidates for diagnosis of HPS.

Perioperative management with phosphodiesterase type 5 inhibitor and prostaglandin E1 for moderate portopulmonary hypertension following adult-to-adult living-donor liver transplantation: a case report

Background

Portopulmonary hypertension (PPH) is a relatively rare but well-recognized complication of end-stage liver disease. Moderate or severe PPH (mean pulmonary artery pressure [mPAP] ≥ 35 mmHg) is usually a contraindication for liver transplantation due to high operation-related mortality. Here, we report on a patient with moderate PPH whose condition was successfully managed with a phosphodiesterase type 5 (PDE5) inhibitor (tadalafil) and prostaglandin E1, who experienced rapid improvement of PPH after living-donor liver transplantation (LDLT).

Case presentation

A 63-year-old woman with alcoholic decompensated cirrhosis was referred to our hospital for LDLT. She had mild dyspnea on exertion as well as fatigue. Echocardiography and subsequent cardiac catheterization revealed a high mPAP (35 mmHg), and she was diagnosed with moderate PPH. We commenced treatment with oral tadalafil for the PPH. A second preoperative echocardiography demonstrated improved PPH, and she underwent LDLT. An intravenous infusion of prostaglandin E1 was introduced instead of tadalafil during and after the operation.

The mPAP value showed a rapid decrease in mPAP value to 22 mmHg in 2 days. After discontinuation of the prostaglandin E1, the mPAP value remained 23 mmHg. Postoperative catheterization 2 months after LDLT showed no exacerbation of PPH. She was discharged on foot 70 days after LDLT in good condition and has shown a good clinical condition more than 2 years after LDLT.

Conclusion

LDLT could be a radical treatment for PPH with careful management and adequate patient selection. PDE5 inhibitor and PGE1 is effective and feasible for perioperative management of the patient with moderate portopulmonary hypertension in LDLT.

Hepatopulmonary Syndrome and Portopulmonary Hypertension: Implications for Liver Transplantation

Hepatopulmonary syndrome (HPS) and portopulmonary hypertension (PoPH) represent serious pulmonary complications of advanced liver diseases. Orthotopic liver transplantation (OLT) is capable of completely resolving the underlying abnormalities associated with HPS. On the other hand, post-OLT response in patients with PoPH is less predictable, although heavily influenced by pre-OLT mean pulmonary arterial pressure. It remains the case that the opportunity to reverse 2 potentially fatal organ dysfunctions in the liver and the lung make HPS and PoPH more than worthy for further clinical investigations.

Left Ventricular Dilation and Pulmonary Vasodilatation after Surgical Shunt for Treatment of Pre-Sinusoidal Portal Hypertension

Objective

The aim of this study was to prospectively investigate the long-term cardiovascular and pulmonary hemodynamic effects of surgical shunt for treatment of portal hypertension (PH) due to Schistosomiasis mansoni.

Location

The University of São Paulo Medical School, Brazil; Public Practice.

Methods

Hemodynamic evaluation was performed with transesophageal Doppler and contrast-enhanced echocardiography (ECHO) on twenty-eight participants with schistosomal portal hypertension. Participants were divided into two groups according to the surgical procedure used to treat their schistosomal portal hypertension within the last two years: group 1—distal splenorenal shunt (DSRS, n = 13) and group 2—esophagogastric devascularization and splenectomy (EGDS, n = 15).

Results

The cardiac output (5.08 ± 0.91 L/min) and systolic volume (60.1 ± 5.6 ml) were increased (p = 0.001) in the DSRS group. DSRS participants had a significant increase (p < 0.0001) in their left ventricular end-systolic and end-diastolic diameters as well as in their left ventricular end-diastolic and end-systolic volumes (p < 0.001) compared with the preoperative period. No statistically significant difference was found in the patients who underwent EGDS. ECHO revealed intrapulmonary vasodilatation (IPV) in 18 participants (64%), 9 DSRS and 9 EGDS (p > 0.05).

Conclusions

The late increase in the cardiac output, stroke volume and left ventricular diameters demonstrated left ventricular dilatation after a distal splenorenal shunt. ECHO revealed a greater prevalence for IPV in patients with schistosomiasis than has previously been described in patients with PH from liver cirrhosis.

Intrapulmonary vascular dilatations are common in portopulmonary hypertension and may be associated with decreased survival

Hepatopulmonary syndrome (HPS) and portopulmonary hypertension (POPH) are pulmonary vascular complications of portal hypertension with divergent clinicopathologic features and management. The presence of intrapulmonary vascular dilatations (IPVDs), detected by agitated saline contrast-enhanced transthoracic echocardiography (cTTE), is an essential feature of HPS but is not typically characteristic of POPH. Although IPVDs have been reported rarely in POPH, the prevalence and significance of this finding have not been systematically studied. We conducted a retrospective chart review of 80 consecutive patients diagnosed with POPH from January 1, 2002 to June 30, 2014 with documentation of cTTE findings, pulmonary hemodynamics, oxygenation, and survival. A total of 34 of the 80 patients (42%) underwent cTTE during initial diagnosis of POPH. IPVDs were detected in 20/34 patients (59%); intracardiac shunting was detected in 9/34 patients (26%; 4 also had IPVDs); and 9 patients (26%) had negative cTTE with no evidence of IPVD or intracardiac shunting. Patients with IPVD had decreased survival as compared to those without IPVD (P = 0.003), a trend that persisted after exclusion of liver transplant recipients (P =  0.07). The IPVD group had a trend toward higher Model for End-Stage Liver Disease score with and without incorporating sodium (MELD or MELD-Na; P = 0.05 for both). The right ventricular index of myocardial performance (RIMP) was lower in the IPVD group (median, 0.4 versus 0.6; P = 0.006). Patients with moderate or large IPVDs (n = 6) had worse oxygenation parameters (partial pressure of arterial oxygen, diffusing capacity of the lung for carbon monoxide, and alveolar-arterial oxygen gradient) as compared to the rest of the cohort. Unexpectedly, IPVDs were frequently documented in POPH and associated with decreased survival. To further understand this observation, we recommend screening for IVPD in all patients with POPH.

Cirrhotic Multiorgan Syndrome

Patients with cirrhosis and portal hypertension are at an increased risk of the development of circulatory dysfunction that may potentially result in multiple organ failure. Apart from the liver, this may involve the heart, lungs, kidneys, the immune system, the adrenal glands, and other organ systems. As the disease progresses, the circulation becomes hyperdynamic, and signs of cardiac, pulmonary, and renal dysfunction are observed, in addition to reduced survival. Infections and an altered cardiac function known as cirrhotic cardiomyopathy may be precipitators for the development of other complications such as hepatorenal syndrome. In patients with chronic organ dysfunction, various precipitating events may induce an acute-on-chronic renal failure and acute-on-chronic liver failure that negatively affect the prognosis. Future research on the pathophysiologic mechanisms of the complications and the precipitating factors is essential to understand the basics of the treatment of these challenging conditions. The aim of the present review is to focus on the development and precipitating factors of various organ failures in patients with decompensated cirrhosis.

Diagnosis of pulmonary arterial hypertension

Accurate diagnosis of pulmonary arterial hypertension can be challenging and often requires a high index of clinical suspicion. Use of a variety of noninvasive tests can help define the population of patients in whom invasive cardiac catheterization should be pursued. An understanding of the historical, physical exam, electrocardiographic, radiographic, and echocardiographic clues in the diagnosis is important. A ventilation-perfusion scan and careful assessment for left-to-right shunting are mandatory to avoid missing reasons for pulmonary hypertension that may require nonpharmacologic management. Right heart, and sometimes concomitant left heart, catheterization is required to establish the diagnosis and distinguish pulmonary arterial from pulmonary venous hypertension.

Hepatopulmonary syndrome and portopulmonary hypertension

Hepatopulmonary syndrome and portopulmonary hypertension are 2 of many diseases that affect the lungs in patients with liver disease. The 2 vascular conditions are often confused. We review both hepatopulmonary syndrome and portopulmonary hypertension to better understand their pathophysiologies, clinical presentations, tools to aid in differentiating and diagnosing the disease states, treatment options, and influences on patient prognosis. We also consider patient viability for liver transplantation.

Surgery in a patient with liver disease

Surgery is often needed in patients with concurrent liver disease. The multiple physiological roles of the liver places these patients at an increased risk of morbidity and mortality. Diseases necessitating surgery like gallstones and hernia are more common in patients with cirrhosis. Assessment of severity of liver dysfunction before surgery is important and the risk benefit of the procedure needs to be carefully assessed. The disease severity may vary from mild transaminase rise to decompensated cirrhosis. Surgery should be avoided if possible in the emergency setting, in the setting of acute and alcoholic hepatitis, in a patient of cirrhosis who is child class C or has a MELD score more than 15 or any patient with significant extrahepatic organ dysfunction. In this subset of patients, all possible means to manage these patients conservatively should be attempted. Modified Child-Pugh scores and model for end-stage liver disease (MELD) scores can predict mortality after surgery fairly reliably including nonhepatic abdominal surgery. Pre-operative optimization would include control of ascites, correction of electrolyte imbalance, improving renal dysfunction, cardiorespiratory assessment, and correction of coagulation. Tests of global hemostasis like thromboelastography and thrombin generation time may be more predictive of the risk of bleeding compared with the conventional tests of coagulation in patients with cirrhosis. Correction of international normalized ratio with fresh frozen plasma does not necessarily mean reduction of bleeding risk and may increase the risk of volume overload and lung injury. International normalized ratio liver may better reflect the coagulation status. Recombinant factor VIIa in patients with cirrhosis needing surgery needs further study. Intra-operatively, safe anesthetic agents like isoflurane and propofol with avoidance of hypotension are advised. In general, nonsteroidal anti-inflammatory drug (NSAIDs) and benzodiazepines should not be used. Intra-abdominal surgery in a patient with cirrhosis becomes more challenging in the presence of ascites, portal hypertension, and hepatomegaly. Uncontrolled hemorrhage due to coagulopathy and portal hypertension, sepsis, renal dysfunction, and worsening of liver failure contribute to the morbidity and mortality in these patients. Steps to reduce ascitic leaks and infections need to be taken. Any patient with cirrhosis undergoing major surgery should be referred to a specialist center with experience in managing liver disease.

Elevated levels of endothelin-1 in hepatic venous blood are associated with intrapulmonary vasodilatation in humans

BACKGROUND

Hepatopulmonary syndrome is a pulmonary vascular complication of cirrhosis in which intrapulmonary vasodilatation (IPV) results in hypoxemia. Endothelin-1 (ET-1), produced by proliferating cholangiocytes, has been identified as a mediator of IPV in an animal model of HPS, but the pathophysiology of IPV in humans has not been defined.

AIM

The purpose of this study was to assess whether cirrhosis with IPV, which often leads to HPS, is associated with increased hepatic venous ET-1 blood levels.

METHODS

We performed a prospective cohort pilot study of 40 patients with liver disease undergoing transjugular liver biopsy from November 1, 2008 to September 1, 2009. Patients were categorized according to absence (-) or presence (+) of IPV as determined by bubble-contrasted echocardiography. Hepatic venous blood was assayed for ET-1 by ELISA. The percent volume of cholangiocytes in the liver biopsy specimen was determined by morphometric analysis, as a measure of bile duct proliferation.

RESULTS

Nine subjects were excluded, due to absence of cirrhosis (6) and patent foramen ovale (3). Of the remaining 31 subjects, IPV was present in 18 (58%). Median hepatic venous ET-1 was higher with IPV+ than IPV- at levels of 9.1 pg/mL (range 7.5-11.7) versus 2.1 pg/mL (1.3-5.6), respectively (P = 0.004). ET-1 levels correlated positively with cholangiocyte percent volume (r = 0.72, P < 0.001) but not with measures of liver dysfunction (bilirubin, INR, MELD score, or hepatic venous pressure gradient).

CONCLUSION

In human cirrhosis, increased hepatic venous ET-1 is associated with IPV and increased hepatic cholangiocyte volume.

Management of pulmonary complications in pretransplant patients

This article addresses the most common pulmonary issues that affect liver transplant candidates. Pretransplant diagnostic criteria of these pulmonary problems in liver transplant patients are reviewed. Successful pulmonary management schemes and caveats are described. Risks for liver transplant are emphasized.

Extracorporeal membrane oxygenation as a bridge to liver transplantation for acute respiratory distress syndrome-induced life-threatening hypoxaemia aggravated by hepatopulmonary syndrome

Introduction

Combined with massive lung aeration loss resulting from acute respiratory distress syndrome, hepatopulmonary syndrome, a liver-induced vascular lung disorder characterized by diffuse or localized dilated pulmonary capillaries, may induce hypoxaemia and death in patients with end-stage liver disease.

Methods

The case of such a patient presenting with both disorders and in whom an extracorporeal membrane oxygenation was used is described.

Results

A 51-year-old man with a five-year history of alcoholic cirrhosis was admitted for acute respiratory failure, platypnoea and severe hypoxaemia requiring emergency tracheal intubation. Following mechanical ventilation, hypoxaemia remained refractory to positive end-expiratory pressure, 100% of inspired oxygen and inhaled nitric oxide. Two-dimensional contrast-enhanced (agitated saline) transthoracic echocardiography disclosed a massive right-to-left extracardiac shunt, without patent foramen ovale. Contrast computed tomography (CT) of the thorax using quantitative analysis and colour encoding system established the diagnosis of acute respiratory distress syndrome aggravated by hepatopulmonary syndrome. According to the severity of the respiratory condition, a veno-venous extracorporeal membrane oxygenation was implemented and the patient was listed for emergency liver transplantation. Orthotopic liver transplantation was performed at Day 13. At the end of the surgical procedure, the improvement in oxygenation allowed removal of extracorporeal membrane oxygenation (Day 5). The patient was discharged from hospital at Day 48. Three months after hospital discharge, the patient recovered a correct physical autonomy status without supplemental O₂.

Conclusions

In a cirrhotic patient, acute respiratory distress syndrome was aggravated by hepatopulmonary syndrome causing life-threatening hypoxaemia not controlled by standard supportive measures. The use of extracorporeal membrane oxygenation, by controlling gas exchange, allowed the performing of a successful liver transplantation and final recovery.

Liver regeneration is promoted by increasing serotonin content in rat liver with secondary biliary cirrhosis

AIM

  Liver cirrhosis clinically shows thrombocytopenia and hypersplenism. Although splenectomy is performed to achieve higher platelet count and better hemostasis, the effect of splenectomy for liver cirrhosis remains unclear. The aim of the present study that was focused on serotonin was to investigate the relationship between splenectomy and liver regeneration in rats with secondary biliary cirrhosis.

METHODS

  Liver cirrhosis was induced in Sprague-Dawley rats by bile duct ligation (BDL). In addition, splenectomy and administration of ketanserin, which selectively antagonizes 5-HT2A and 2B serotonin receptors, were performed. Three weeks after the interventions, whole blood, plasma, serum, and liver specimens were obtained for the following studies: peripheral platelet counts, hemodynamics of serotonin, histopathological examination, immunostaining, and quantification of mRNA expression.

RESULTS

  Splenectomy induced thrombocytosis, and increased serotonin content in cirrhotic liver. Stimulation of liver regeneration was indicated by the following parameters: hepatocyte ratio to the entire liver area, Ki67-positive hepatocyte count, and expression of phosphorylated extracellular signal-regulated kinases. This enhancement of liver regeneration was negated by ketanserin.

CONCLUSION

  Our results showed that splenectomy promoted liver regeneration by increasing serotonin content in liver even under cirrhotic conditions.

Serial pulse oximetry in hepatopulmonary syndrome

BACKGROUND/AIM

The natural history of hepatopulmonary syndrome (HPS) is poorly characterized and how hypoxemia develops and progresses over time is unclear. We evaluated oxygenation over time in advanced liver disease patients with and without HPS using serial pulse oximetry.

METHODS

Data from a prospective cohort of patients evaluated for liver transplantation were analyzed. All patients with significant cardiopulmonary disease were excluded and patients with and without HPS were compared. Arterial oxygen saturation measurements with pulse oximetry (SpO(2)) were recorded serially from initial evaluation until transplantation or last clinic visit on record. Patients with SpO(2) measurements at ≥ 2 visits were included.

RESULTS

A total of 22 HPS patients were compared to 32 non-HPS patients (18 with intrapulmonary vasodilation on contrast echocardiography, CE) over a mean duration of 20 months and 4 SpO(2) measurements. HPS patients had lower SpO(2) at baseline (96.8 vs. 98.4%, P = 0.02) and at end of follow-up (95.8 vs. 98.2%, P = 0.02), and were more likely to have a ≥ 2% reduction (P = 0.04) and faster decline in SpO(2) as compared to non-HPS patients (F = 2.2, P = 0.04). HPS patients with lower SpO(2) and/or PO(2) at baseline appeared more likely to worsen over time. There was no difference in SpO(2) over time between the 2 non-HPS subgroups (- or +CE).

CONCLUSIONS

HPS patients have a significant decline in SpO(2) over time compared to non-HPS patients, and therefore, pulse oximetry may be useful for monitoring cirrhotics for development or worsening of HPS. Presence of intrapulmonary vasodilation in the absence of hypoxemia does not appear to affect SpO(2) over time.

Living donor liver transplantation for end-stage liver disease with severe hepatopulmonary syndrome: report of a case

Hepatopulmonary syndrome (HPS) is a serious complication of terminal liver disease, which manifests as severe hypoxia without any pulmonary anatomic or functional causes. The precise indications for liver transplantation in patients with severe HPS also remain unclear. A 49-year old woman was referred to our department for investigation and management of liver cirrhosis with severe hypoxia (PaO(2), 38 mmHg). A pulmonary perfusion scintigram showed an intrapulmonary shunt ratio of 40%, confirming a diagnosis of severe HPS. She underwent living donor liver transplantation using a right lobe graft donated by her 27-year-old daughter. Her post-transplant graft function was excellent, and her oxygenation recovered slowly but steadily. She was discharged from hospital on posttransplant day 39 with an SpO(2) of 94% under 3 l/min of O(2), delivered nasally. Despite the severity of the HPS, her postoperative recovery was smooth after the liver transplant.

Genetic risk factors for hepatopulmonary syndrome in patients with advanced liver disease

BACKGROUND & AIMS

Hepatopulmonary syndrome (HPS) affects 10%-30% of patients with cirrhosis and portal hypertension and significantly increases mortality. Studies in experimental models indicate that pulmonary angiogenesis contributes to the development of HPS, but pathogenesis in humans is poorly understood. We investigated genetic risk factors for HPS in patients with advanced liver disease.

METHODS

We performed a multicenter case-control study of patients with cirrhosis being evaluated for liver transplantation. Cases had an alveolar-arterial oxygen gradient > or = 15 mm Hg (or > or =20 mm Hg if age > 64 years) and contrast echocardiography with late appearance of microbubbles after venous injection of agitated saline (intrapulmonary vasodilatation); controls did not meet both criteria for case status. The study sample included 59 cases and 126 controls. We genotyped 1086 common single nucleotide polymorphisms (SNPs) in 94 candidate genes.

RESULTS

Forty-two SNPs in 21 genes were significantly associated with HPS after adjustments for race and smoking. Eight genes had at least 2 SNPs associated with disease: CAV3, ENG, NOX4, ESR2, VWF, RUNX1, COL18A1, and TIE1. For example, rs237872 in CAV3 showed an odds ratio of 2.75 (95% confidence interval: 1.65-4.60, P = .0001) and rs4837192 in ENG showed an odds ratio of 0.35 (95% confidence interval: 0.14-0.89, P = .027). Furthermore, variation in CAV3 and RUNX1 was associated with HPS in gene-based analyses.

CONCLUSIONS

Polymorphisms in genes involved in the regulation of angiogenesis are associated with the risk of HPS. Further investigation of these biologic pathways might elucidate the mechanisms that mediate the development of HPS in certain patients with severe liver disease.

Portopulmonary hypertension: short review

Portopulmonary hypertension (PoPH) is an underrecognized complication of portal hypertension, related to cirrhosis and noncirrhotic portal hypertension. PoPH has been found in 5-6% of patients with decompensated liver disease and may adversely affect outcome after liver transplantation. The prevalence of PoPH is unrelated to the severity of liver disease but associated with female sex and underlying autoimmune liver disease. Diagnosis of PoPH is based on screening with Doppler echocardiography and confirmation by right-heart catheterization. Treatment options with proven efficacy in idiopathic pulmonary hypertension include endothelin receptor antagonists, prostanoids, and sildenafil. In PoPH, such targeted treatment was found to be safe in small uncontrolled studies but randomized trials demonstrating its benefit are lacking.

Non-congenital heart disease associated pediatric pulmonary arterial hypertension

Recognition of causes of pulmonary hypertension other than congenital heart disease is increasing in children. Diagnosis and treatment of any underlying cause of pulmonary hypertension is crucial for optimal management of pulmonary hypertension. This article discusses the available knowledge regarding several disorders associated with pulmonary hypertension in children: idiopathic pulmonary arterial hypertension (IPAH), pulmonary capillary hemangiomatosis, pulmonary veno-occlusive disease, hemoglobinopathies, hepatopulmonary syndrome, portopulmonary hypertension and HIV. Three classes of drugs have been extensively studied for the treatment of IPAH in adults: prostanoids (epoprostenol, treprostinil, iloprost, beraprost), endothelin receptor antagonists (bosentan, sitaxsentan, ambrisentan), and phosphodiesterase inhibitors (Sildenafil, tadalafil). These medications have been used in treatment of children with pulmonary arterial hypertension, although randomized clinical trial data is lacking. As pulmonary vasodilator therapy in certain diseases may be associated with adverse outcomes, further study of these medications is needed before widespread use is encouraged.

Hepatopulmonary syndrome in patients with Schistosoma mansoni periportal fibrosis

Hepatopulmonary syndrome (HPS) is characterized by the presence of liver disease, arterial hypoxemia and intrapulmonary vascular dilatation (IPVD). IPVD includes diffused or localized dilated pulmonary capillaries and, less commonly, pleural and pulmonary arteriovenous communications. The aim of the present study was to investigate the occurrence of HPS in patients with Schistosoma mansoni periportal fibrosis in treatment at a university hospital in northeastern Brazil.

PATIENTS AND METHODS

Eighty-four patients were enrolled in the study between April and July 2007 and underwent arterial blood gas analysis. Patients with an alveolar-arterial oxygen gradient (DA-aO(2)) > or = 15 mmHg were submitted to contrast-enhanced transthoracic echocardiogram (CE-TTE) with saline microbubbles. The diagnostic criterion for HPS was DA-aO(2) > or = 15 mmHg associated to IPVD, as identified through CE-TTE. Patients with HPS underwent contrast-enhanced 16-channel multidetector-row computed tomography (MDCT) of the thorax.

RESULTS

Twenty-two patients (26.19%) had DA-aO(2) > or = 15 mmHg (mean value=20.86+/-7.91). CE-TTE was positive for IPVD in five of the 22 patients with DA-aO(2) > or = 15 mmHg and all these patients had hepatosplenic disease, revealing a 6% prevalence of HPS (CI: 1.96-13.35) in the overall population of 84 patients, with a 10.2% prevalence in the group with hepatosplenic disease. The following were the 16-channel MDCT findings in these five patients: dilated peripheral pulmonary vasculature (100%); ratio of segmental arterial diameter to adjacent bronchial diameter equal to or greater than 2:1 (100%); higher number of visible terminal vessel branches in lung dependent regions (40%); and micronodules associated with subpleural surface centrilobular vessels (40%). No patient had evidence of arteriovenous fistula. These findings reveal that HPS occurs (usually in a mild form) in patients with Schistosoma mansoni periportal fibrosis and portal hypertension seems to be an important factor related to the occurrence of HPS in such cases.

Hepatopulmonary syndrome: an update

Hepatopulmonary syndrome (HPS) is a clinical threesome composed of liver disease, intrapulmonary vascular dilatation (IPVD) and arterial gas abnormalities. Its occurrence has been described in up to 32% of cirrhotic candidates for liver transplantation. It also affects non-cirrhotic patients with portal hypertension. Its pathogenesis is not well defined, but an association of factors such as imbalance in the endothelin receptor response, pulmonary microvascular remodeling and genetic predisposition is thought to lead to IPVD. Diagnosis is based on imaging methods that identify these dilatations, such as contrast echocardiography or perfusion scintigraphy with 99mTc, as well as analysis of arterial gases to identify elevated alveolar-arterial differences in O2 or hypoxemia. There is no effective pharmacological treatment and complete resolution only occurs through liver transplantation. The importance of diagnosing HPS lies in prioritizing transplant candidates, since presence of HPS is associated with worse prognosis. The aim of this paper was to review the pathogenetic theories and current diagnostic criteria regarding HPS, and to critically analyze the prioritization of patients with HPS on the liver transplant waiting list. Searches were carried out in the Medline (Medical Literature Analysis and Retrieval System Online) via PubMed, Cochrane Library and Lilacs (Literatura Latino-Americana e do Caribe em Ciências da Saúde) databases for articles published between January 2002 and December 2007 involving adults and written either in English or in Portuguese, using the term hepatopulmonary syndrome. The studies of greatest relevance were included in the review, along with text books and articles cited in references that were obtained through the review.

Liver transplantation: from Child to MELD

The widespread availability of transplantation in most major medical centers in the United States, together with a growing number of transplant candidates, has made it necessary for primary care providers, especially internal medicine and family practice physicians to be active in the clinical care of these patients before and after transplantation. This review provides an overview of the liver transplantation process, including indications, contraindications, time of referral to a transplant center, the current organ allocation system, and briefly touches on the expanding field of living donor liver transplantation.

Pulmonary hypertension after liver transplantation: case presentation and review of the literature

Hepatopulmonary syndrome and portopulmonary hypertension are the most common pulmonary vascular complications in patients with cirrhosis. Usually but not universally mutually exclusive, they each may present prior to liver transplantation and, if severe enough, may be a contraindication to transplant. However, there have been a number of case reports describing patients developing pulmonary hypertension de novo after liver transplantation. This report describes one such patient from our institution and reviews the medical literature describing this unusual clinical entity.

Serotonin transporter polymorphisms in patients with portopulmonary hypertension

BACKGROUND

The long allele of a functional promoter polymorphism in the serotonin transporter (SERT) is associated with an increased risk of some forms of pulmonary arterial hypertension. We hypothesized that the long allele or other polymorphisms in SERT would be associated with an increased risk of portopulmonary hypertension (PPHTN) in patients with advanced liver disease.

METHODS

We performed a multicenter case-control study. Subjects undergoing liver transplant evaluation at seven centers were prospectively screened for the presence of PPHTN using transthoracic echocardiography. PPHTN was confirmed by right heart catheterization using standard criteria.

RESULTS

The study sample included 30 case patients with PPHTN and 109 control subjects with advanced liver disease. There was no significant association between the long allele and case status in an adjusted additive model (odds ratio, 0.63; 95% confidence interval, 0.33 to 1.21; p = 0.17). If anything, LL genotype tended to be associated with a lower risk of PPHTN. There were no associations between other SERT polymorphisms and PPHTN.

CONCLUSIONS

SERT polymorphisms are not associated with the risk of PPHTN in patients with advanced liver disease. Other clinical or genetic risk factors may play a role in this complication of portal hypertension.

Pulmonary hypertension is associated with reduced patient survival after kidney transplantation

INTRODUCTION

Pulmonary hypertension (PH) is common in patients on dialysis where it is associated with reduced survival. The possible association between PH and kidney transplant recipient survival has not been previously evaluated.

METHODS

In this retrospective study, we screened for PH pretransplant in 215 transplant candidates using cardiac echocardiography and measurements of right ventricular systolic pressure (RVSP).

RESULTS

Sixty-eight percent of patients had normal RVSP (<35 mm Hg), 47 (22%) had mild to moderately elevated RVSP (36-50), and 22 (10%) had markedly elevated RVSP more than 50 suggestive of severe PH. Time on dialysis was the strongest correlate of an elevated RVSP (r=0.253, P<0.001) and this relationship was independent of other variables. Elevated RVSP was observed in 25%, 25%, 38%, and 58% of patients not on dialysis, on dialysis for less than 1 year, more than 1 to 2 years, or more than 2 years, respectively. An RVSP more than 50 was associated with significantly reduced posttransplant survival (hazard ratio =3.75 [1.17-11.97], P=0.016). This relationship seemed to be independent of other variables including older age, reduced left ventricular ejection fraction, low serum albumin, and delayed graft function.

CONCLUSION

These analyses suggest for the first time that pretransplant PH correlates with patient survival after kidney transplantation.

Impact of hepatopulmonary syndrome on quality of life and survival in liver transplant candidates

BACKGROUND & AIMS

Hepatopulmonary syndrome (HPS) affects 10%-30% of patients with cirrhosis and portal hypertension, but the impact on functional status, quality of life, and survival is poorly defined. We assessed the impact of HPS in patients evaluated for liver transplantation.

METHODS

We performed a prospective multicenter cohort study of patients being evaluated for liver transplantation in 7 academic centers in the United States. Patients with HPS (defined as an increased alveolar-arterial oxygen gradient with intrapulmonary vasodilation) were compared with those without HPS in terms of demographics and clinical variables. New York Heart Association functional class, quality of life, and survival were assessed.

RESULTS

Seventy-two patients with HPS and 146 patients without HPS were compared. There were no differences in age, sex, or etiology or severity of liver disease between the groups; however, patients with HPS were less likely to have a history of smoking (P = .03). Patients with HPS had worse New York Heart Association functional class (P = .005) and had significantly worse quality of life in certain domains compared with patients without HPS. In addition, patients with HPS also had a significantly increased risk of death compared with patients without HPS despite adjustment for age, sex, race/ethnicity, Model for End-Stage Liver Disease score, and liver transplantation (adjusted hazard ratio = 2.41; 95% confidence interval, 1.31-4.41; P = .005).

CONCLUSIONS

HPS was associated with a significant increase in risk of death as well as worse functional status and quality of life in patients evaluated for liver transplantation.

Liver transplantation for pulmonary vascular complications of pediatric end-stage liver disease

PURPOSE

Hepatopulmonary syndrome (HPS) and portopulmonary hypertension (PPH) are poorly understood pulmonary complications of end-stage liver disease (ESLD). We present a case series of children with HPS and PPH.

METHODS

After institutional review board approval, query of our medical database identified children 0 to 18 years of age with ESLD diagnosed with HPS or PPH. Data were collected via chart review.

RESULTS

We identified 7 children with either HPS (n = 5) or PPH (n = 2). Patients with HPS presented with progressive dyspnea over a mean of 7 months (range, 4-12 months) at a mean of 13 years (range, 5-17 years) of age. Pulmonary shunting by albumin perfusion scan averaged 41% (range, 20%-66%) with an initial mean resting SpO(2) of 88% (range, 84%-94%) and mean SpO(2) during exertion of 79% (range, 60%-89%). Four patients required supplemental O(2) and, upon United Network for Organ Sharing (UNOS) appeal, received pediatric model for ESLD (or Child-Pugh) score exceptions, enabling them to undergo orthotopic liver transplant (OLT) within 1-2 months. The fifth patient was initially rejected by the UNOS regional review board, but 6 months of worsening hypoxemia led to OLT 2 months after successful UNOS appeal. All patients with HPS undergoing OLT experienced complete resolution of hypoxemia within 8 months. Both children with PPH were treated with intravenous epoprostenol, which lowered or stabilized mean pulmonary artery pressure and bridged them to OLT within 7 months of listing. Overall, there were no pulmonary complications; however, 1 patient with PPH expired shortly after OLT. The remaining patients are alive at a median follow-up of 27 months (range, 6-96 months).

CONCLUSION

Hepatopulmonary syndrome and PPH are uncommon complications of ESLD in children. Epoprostenol can bridge PPH patients to OLT. OLT leads to rapid resolution of HPS and PPH and currently represents the only successful treatment for these children.

Current concepts in the evaluation of patients for liver transplantation

Candidates for liver transplantation undergo a thorough medical, surgical, psychosocial and financial evaluation prior to listing for transplantation. Prioritization for allocating livers is based upon the model for end-stage liver disease score and waiting-time mortality with the fundamental concept of giving organs to the sickest first. In the upcoming years the allocation system may be modified to include other factors associated with mortality, such as serum sodium, and may incorporate both pre- and post-transplant mortality. Strategies to expand the donor pool include utilizing livers from donors after cardiac death, split liver transplantation and living donor liver transplantation. Future challenges for liver transplantation will include the obesity epidemic and the prevention and treatment of recurrent disease, particularly hepatitis C.

Diagnosis of pulmonary arterial hypertension

Accurate diagnosis of pulmonary arterial hypertension is a challenging and complex process that requires a high index of clinical suspicion from even the most astute clinician. This article discusses the use of a variety of noninvasive tests that can help define the population of patients in whom invasive cardiac catheterization should be pursued. It points out the vagaries and limitations of electrocardiography and the radiographic and echocardiographic clues to the diagnosis. Ultimately, right- and, often, concomitant left-heart catheterization is required to establish the diagnosis and distinguish pulmonary arterial hypertension from pulmonary venous hypertension.

Preoperative evaluation of patients with liver disease

Patients with end-stage liver disease often undergo surgery for indications other than liver transplantation. These patients have an increased risk of morbidity and mortality that is related to their underlying liver disease. Assessments of surgical risk provide a basis for discussion of risks and benefits, treatment decision making, and for optimal management of patients for whom surgery is planned. The most useful indicators of surgical risk are indices that predict advanced disease, such as the Child-Turcotte-Pugh score, or those that predict prognosis, such as the Model for End-stage Liver Disease score. Careful preoperative risk assessment, patient selection, and management of various manifestations of advanced disease might decrease morbidity and mortality from nontransplant surgery in patients with liver disease.

Portopulmonary hypertension

Portopulmonary hypertension (PPHT) is defined as precapillary pulmonary hypertension accompanied by hepatic disease or portal hypertension. Pulmonary hypertension results from excessive pulmonary vascular remodeling and vasoconstriction. These histological alterations have been indistinguishable from those of other forms of pulmonary arterial hypertension. Factors involved in the pathogenesis of PPHT include volume overload, hyperdynamic circulation, and circulating vasoactive mediators. The disorder has a substantial impact on survival and requires focused treatment. Liver transplantation in patients with moderate to severe PPHT is associated with a significantly reduced survival rate. The best medical treatment for patients with PPHT is controversial; most authors currently regard continuous intravenous application of prostacyclin as the treatment of choice for patients with severe PPHT. There is only very limited reported experience with inhaled prostacyclin or its analog, iloprost. Increasing evidence of the efficacy of the endothelin-receptor antagonist bosentan and of the phosphodiesterase-5 inhibitor sildenafil is emerging in highly selected patients with PPHT. In the future, a combination therapy of the above-mentioned agents might become a therapeutic option. Other agents such as beta-blockers seem to be harmful to patients with moderate to severe portopulmonary hypertension. Up-to-date, randomized, double-blind, controlled clinical trials are lacking and are needed urgently.