The hepatopulmonary syndrome. Effect of liver transplantation

Pulmonary Assessment of the Liver Transplant Recipient

Respiratory symptoms and hypoxemia can complicate chronic liver disease and portal hypertension. Various pulmonary disorders affecting the pleura, lung parenchyma, and pulmonary vasculature are seen in end-stage liver disease, complicating liver transplantation (LT). Approximately 8% of cirrhotic patients in an intensive care unit develop severe pulmonary problems. These disorders affect waiting list mortality and posttransplant outcomes. A thorough history, physical examination, and appropriate laboratory tests help diagnose and assess the severity to risk stratify pulmonary diseases before LT. Hepatopulmonary syndrome (HPS), portopulmonary hypertension (POPH), and hepatic hydrothorax (HH) are respiratory consequences specific to cirrhosis and portal hypertension. HPS is seen in 5-30% of cirrhosis cases and is characterized by impaired oxygenation due to intrapulmonary vascular dilatations and arteriovenous shunts. Severe HPS is an indication of LT. The majority of patients with HPS resolve their hypoxemia after LT. When pulmonary arterial hypertension occurs in patients with portal hypertension, it is called POPH. All other causes of pulmonary arterial hypertension should be ruled out before labeling as POPH. Since severe POPH (mean pulmonary artery pressure [mPAP] >50 mm Hg) is a relative contraindication for LT, it is crucial to screen for POPH before LT. Those with moderate POPH (mPAP >35 mm Hg), who improve with medical therapy, will benefit from LT. A transudative pleural effusion called hepatic hydrothorax (HH) is seen in 5-10% of people with cirrhosis. Refractory cases of HH benefit from LT. In recent years, increasing clinical expertise and advances in the medical field have resulted in better outcomes in patients with moderate to severe pulmonary disorders, who undergo LT.

First presentation of portal hypertension complicated by hepatopulmonary syndrome

Hepatopulmonary syndrome (HPS) is a serious complication of chronic liver disease, characterised by portal hypertension and arterial hypoxaemia due to intrapulmonary vascular dilatation. We report an unusual case in which a 27-year-old man had a first presentation of portal hypertension and cirrhosis complicated by HPS. This patient presented with progressive dyspnoea on exertion and deterioration in mobility, with a type 1 respiratory failure and increased oxygen demand. A bubble echocardiogram showed a possible right-to-left shunt, CT aortogram displayed evidence of portal hypertension and cirrhosis, and liver biopsy findings were consistent with alpha-1 antitrypsin deficiency. The patient's increased oxygen demand was subsequently treated with continuous positive airway pressure before he was discharged with 8 L home oxygen. With no current established medical therapy for HPS, the patient was assessed for liver transplantation and a decision was made in favour of this.

Treatment of Severe Acute on Chronic Liver Failure: Management of Organ Failures, Investigational Therapeutics, and the Role of Liver Transplantation

Acute on chronic liver failure (ACLF) is a unique syndrome that afflicts patients with chronic liver disease and results in high short-term mortality, in the setting of organ system failures. Given this prognosis, there is an urgent need to understand risk factors for this condition, for appropriate medical management of organ failures, and for selection criteria for patients who may benefit from liver transplantation (LT). Although several definitions exist to identify ACLF, all of them are designed to identify patients with uniquely high mortality. Currently, management of severe ACLF relies on best supportive care for specific organ failures. Thromboelastography should guide the evaluation of coagulation pathways and hyperfibrinolysis in ACLF; prophylactic blood product transfusions and thrombopoetin agonists are not recommended. Combination therapy with terlipressin and albumin has been shown to be efficacious in the management of the hepatorenal syndrome but should be administered with caution in patients with ACLF-3. Recent data have characterized the role of beta-blockers and transjugular intrahepatic portosystemic shunt placement in the management of ACLF. Investigational therapies such as extracorporeal liver support and hepatocyte stem cell therapies have shown promise; larger scale studies may better define the subpopulations of patients with ACLF mostly likely to benefit from these evolving therapeutics. Regarding LT in ACLF, data suggest that even patients with 3 or more organ system failures may have a 1-year survival >80%. However, further efforts are needed to understand the predictors of post-LT survival to facilitate LT criteria for this condition.

Pulmonary Complications of Portal Hypertension

The most common pulmonary complications of chronic liver disease are hepatic hydrothorax, hepatopulmonary syndrome, and portopulmonary hypertension. Hepatic hydrothorax is a transudative pleural effusion in a patient with cirrhosis and no evidence of underlying cardiopulmonary disease. Hepatic hydrothorax develops owing to the movement of ascitic fluid into the pleural space. Hepatopulmonary syndrome and portopulmonary hypertension are pathologically linked by the presence of portal hypertension; however, their pathophysiologic mechanisms are significantly different. Hepatopulmonary syndrome is characterized by low pulmonary vascular resistance secondary to intrapulmonary vascular dilatations and hypoxemia; portopulmonary hypertension features elevated pulmonary vascular resistance and constriction/obstruction within the pulmonary vasculature.

Intrapulmonary vascular dilation in children with chronic liver diseases: pre- and post-liver transplantation

BACKGROUND AND STUDY AIMS

Chronic liver disease (CLD) can cause hepatopulmonary syndrome (HPS), defined as triad of liver disease, hypoxemia, and intrapulmonary vascular dilation (IPVD). The aim of this study was to determine the evidence of IPVD in a cohort of pediatric patients with CLD pre- and post-liver transplantation (LT).

MATERIAL AND METHODS

All pediatric patients with CLD listed for LT were studied. Pulse oxygen saturation (SpO(2)), technetium-99m-labeled macroaggregated albumin ((99m)Tc- MAA) perfusión scan (positive test: uptake of the isotope ≥ 6% in the brain), and echocardiography with saline bubble test (SBT) were performed. SBT was re-evaluated at 3-6 months after LT. Grading of SBT included grade 0 (no bubble), I (1-9 bubbles), grade II (10-20 bubbles), and grade III (> 20 bubbles).

RESULTS

Eighteen patients, median age 22.5 months (8-108), were enrolled. Most had biliary atresia (77.8%). Pre-LT, all patients had SpO(2) of 100% and none had positive (99)mTc- MAA perfusion scan. Two patients (11%) had negative SBT (grade 0), 1 (5.5%) had grade I, 3 (16.5%) had grade II, and 12 (67%) had grade III, respectively. Post-LT SBT became negative in all survivors (n = 16), (p = 0.0001).

CONCLUSIONS

Most cirrhotic children in this cohort study had evidence of IPVD by positive SBT. However, none of these met the criteria for diagnosis of HPS. This evidence of IPVD subsided after LT.

Pulmonary Vessel Cross-sectional Area before and after Liver Transplantation: Quantification with Computed Tomography

RATIONALE AND OBJECTIVES

Pulmonary vascular complications of liver disease have a substantial impact on morbidity and mortality in patients who undergo liver transplant. The effect of liver transplantation on the pulmonary vasculature in patients without pulmonary vascular disease, however, has not been described. This study was undertaken to characterize the regional effect of liver transplant on the cross-sectional area (CSA) of pulmonary vessels.

MATERIALS AND METHODS

We performed a single-center, retrospective, cohort study of patients who had a liver transplant between 2002 and 2012 and who had chest computed tomography scans within 1 year before and after transplant. Using ImageJ software, we measured the CSA of small pulmonary vessels (0-5 mm(2)) and the total lung CSA to calculate the percent CSA of pulmonary vessels <5 mm (%CSA<5) at the level of the aortic arch, carina, and right inferior pulmonary vein (RIPV). Pretransplant and posttransplant, %CSA<5 were compared, and associations of pretransplant %CSA<5 with clinical parameters were measured.

RESULTS

There was a significant decrease in %CSA<5 at the level of the RIPV (0.19% [interquartile range {IQR}, 0.15-0.26] before vs. 0.15% [IQR, 0.12-0.21] after; P = .0003), with a median change of -16.2% (IQR, -39.3 to 3.9) posttransplant. Changes at the level of the aortic arch and carina were not significant. Pretransplant RIPV %CSA<5 was not significantly correlated with severity of liver disease or oxygenation but was inversely correlated with percent change in %CSA<5 (r = -0.39; P = .0039).

CONCLUSIONS

This is the first study to describe a significant regional change in the pulmonary vessels of patients without known pulmonary vascular disease who undergo liver transplant.

Management of Complications of End-Stage Liver Disease in the Intensive Care Unit

The management of critically ill patients with end-stage liver disease can be challenging due to the vulnerability of this population and the wide-ranging complications of the disease. This review proposes an approach based on the major organ systems affected, to provide a framework for managing the most common complications. Although considerable practice variation exists, a focus on the evidence behind the most common practices will ensure the development of the optimal skillset to appropriately manage this disease.

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.

Evaluation of liver transplant candidates: A pulmonary perspective

Chronic liver disease is one of the leading causes of mortality and morbidity in the worldwide adult population. Liver transplant is the gold standard therapy for end-stage liver disease and many patients are on the waiting list for a transplant. A variety of pulmonary disorders are encountered in cirrhotic patients. Pleura, lung parenchyma, and pulmonary vasculature may be affected in these patients. Hypoxemia is relatively common and can be asymptomatic. Hepatopulmonary syndrome should be investigated in hypoxic cirrhotic patients. Gas exchange abnormalities are common and are generally correlated with the severity of liver disease. Both obstructive and restrictive types of airway disease can be present. Abnormal diffusion capacity is the most frequently observed pulmonary function disorder in patients with cirrhosis. Hepatic hydrothorax is another finding which is usually seen in conjunction with, but occasionally without ascites. Portopulmonary hypertension is a complication of long standing liver dysfunction and when severe, is accepted as a containdication to liver transplant. Since respiratory disorders are common and have significant impact on postoperative outcome in patients undergoing liver transplant, a careful preoperative pulmonary assessment is important.

Management of cardiopulmonary complications of cirrhosis

Advanced portal hypertension accompanying end-stage liver disease results in an altered milieu due to inadequate detoxification of blood from splanchnic circulation by the failing liver. The portosystemic shunts with hepatic dysfunction result in an increased absorption and impaired neutralisation of the gastrointestinal bacteria and endotoxins leads to altered homeostasis with multiorgan dysfunction. The important cardiopulmonary complications are cirrhotic cardiomyopathy, hepatopulmonary syndrome, portopulmonary hypertension, and right-sided hydrothorax.

[Perioperative anesthesia management of extended partial liver resection. Pathophysiology of hepatic diseases and functional signs of hepatic failure]

The importance of partial liver resection as a therapeutic option to cure hepatic tumors has increased over the last decades. This has been influenced on the one hand by advances in surgical and anesthetic management resulting in a reduced mortality after surgery and on the other hand by an increased incidence of hepatocellular carcinoma. Nowadays, partial resection of the liver is performed safely and as a routine operation in specialized centers. This article describes the pathophysiological changes secondary to liver failure and assesses the perioperative management of patients undergoing partial or extended liver resection. It looks in detail at the preoperative assessment, the intraoperative anesthetic management including fluid management and techniques to reduce blood loss as well as postoperative analgesia and intensive care therapy.

Reversal of severe hepatopulmonary syndrome in chronic hepatic cirrhosis by living donor liver transplantation: report of two cases

Severe hepatopulmonary syndrome (HPS) is a rare complication of decompensated liver cirrhosis and a relative contraindication for liver transplantation. This report describes the treatment of two cases with severe HPS resulting from chronic liver failure by living donor liver transplantation (LDLT). The clinical data of the two cases were reviewed. The parameters included the intrapulmonary shunt ratio as measured by (99m)Tc pulmonary scintigraphy, perioperative treatment and examination results, and the duration of post-transplant hypoxemia. Liver dysfunction was reversed in both patients 2-3 weeks after LDLT. Both patients experienced slightly increased intrapulmonary shunt ratios in the first postoperative month, followed by substantial decreases at postoperative days 90 and 361. These findings suggest severe HPS can be resolved by LDLT. Pulmonary infection requires proper treatment and may be anticipated during the early postoperative course. The differences in the intrapulmonary shunt ratio between these patients may contribute to the differences in the time required for rehabilitation.

Coexisting hepatopulmonary syndrome and portopulmonary hypertension: implications for liver transplantation

Hepatopulmonary syndrome (HPS) and portopulmonary hypertension (POPH) represent pulmonary complications of liver disease and portal hypertension. The underlying pathophysiology behind these entities is complex and involves different effects of vasoactive substances on the pulmonary vasculature, among them endothelin-1 and nitric oxide (NO). Hepatopulmonary syndrome results from vasodilation, intrapulmonary shunting, and hypoxia. In contrast, portopulmonary hypertension is predominantly owing to generalized vasoconstriction that leads to remodeling and an increase in pulmonary vascular resistance, but is rarely associated with hypoxia. We present a case report in which these 2 processes with opposing pathologic mechanisms coexist in the same patient. We also conducted a literature search to identify other documented cases of coexisting hepatopulmonary syndrome and portopulmonary hypertension, common clinical features of these patients, and outcomes with or without treatment. Our case highlights the importance of recognizing the coexistence of these 2 disease processes, as they may occur simultaneously and affect the approach to treatment, including liver transplantation.

Respiratory failure and hypoxemia in the cirrhotic patient including hepatopulmonary syndrome

PURPOSE OF REVIEW

Liver cirrhosis and portal hypertension present with three unique pulmonary complications that are the subject of ongoing clinical research: hepatopulmonary syndrome, portopulmonary hypertension (POPH), and hepatic hydrothorax. The present article is based on a review of the current literature on how to manage these disorders, which are highly important to both anesthesiologists and intensive care physicians.

RECENT FINDINGS

Hepatopulmonary syndrome leads to progressive hypoxemia through diffuse vasodilatation of the pulmonary microcirculation. Liver transplantation, although associated with increased mortality, is the only viable treatment. POPH occurs when vascular remodeling triggers an increase in pulmonary artery pressure and resistance. The role of liver transplantation in POPH is controversial given the excessive mortality in patients with moderate to severe POPH. Medical treatment is able to decrease pulmonary artery pressures, though multicenter randomized controlled trials showing improved outcome are lacking to date. Ultrasound plays an increasingly important role in the diagnosis of all three conditions.

SUMMARY

Patients with end-stage liver disease are at risk for respiratory failure and hypoxemia and need to be screened for hepatopulmonary syndrome, POPH, and hepatic hydrothorax. Failure to timely recognize and adequately treat these complications of cirrhosis may have severe consequences.

Improvement in hepatopulmonary syndrome after methadone withdrawal: a case report with implications for disease mechanism

Spontaneous resolution of hepatopulmonary syndrome (HPS) without liver transplantation or improvement in the underlying liver disease has rarely been reported in the literature. Increased endogenous production of nitric oxide has been implicated in the pathogenesis of HPS. We report the case of a 50-year-old man with hepatitis C cirrhosis who demonstrated dramatic improvement in HPS after withdrawal from chronic methadone therapy. We speculate on the potential role of opiate receptors in the pulmonary vasculature and their effect on nitric oxide signaling as a potential mechanism accounting for the patient's clinical improvement.

Cardiovascular changes in cirrhosis: pathogenesis and clinical implications

Liver cirrhosis is associated with a wide range of cardiovascular abnormalities including hyperdynamic circulation, cirrhotic cardiomyopathy, and pulmonary vascular abnormalities. The pathogenic mechanisms of these cardiovascular changes are multifactorial and include neurohumoral and vascular dysregulations. Accumulating evidence suggests that cirrhosis-related cardiovascular abnormalities play a major role in the pathogenesis of multiple life-threatening complications including hepatorenal syndrome, ascites, spontaneous bacterial peritonitis, gastroesophageal varices, and hepatopulmonary syndrome. Treatment targeting the circulatory dysfunction in these patients may improve the short-term prognosis while awaiting liver transplantation. Careful fluid management in the immediate post-transplant period is extremely important to avoid cardiac-related complications. Liver transplantation results in correction of portal hypertension and reversal of all the pathophysiological mechanisms that lead to the cardiovascular abnormalities, resulting in restoration of a normal circulation. The following is a review of the pathogenesis and clinical implications of the cardiovascular changes in cirrhosis.

Pulmonary artery embolotherapy in a patient with type I hepatopulmonary syndrome after liver transplantation

Although liver transplantation (LT) is the only effective treatment option for hepatopulmonary syndrome (HPS), the post-LT morbidity and mortality have been high for patients with severe HPS. We performed post-LT embolotherapy in a 10-year-old boy who had severe type I HPS preoperatively, but he failed to recover early from his hypoxemic symptoms after an LT. Multiple embolizations were then successfully performed on the major branches that formed the abnormal vascular structures. After the embolotherapy, the patient had symptomatic improvement and he was discharged without complications.

Constitutively active endothelial Notch4 causes lung arteriovenous shunts in mice

Lung arteriovenous (AV) shunts or malformations cause significant morbidity and mortality in several distinct clinical syndromes. For most patients with lung AV shunts, there is still no optimal treatment. The underlying molecular and cellular etiology for lung AV shunts remains elusive, and currently described animal models have insufficiently addressed this problem. Using a tetracycline-repressible system, we expressed constitutively active Notch4 (Notch4*) specifically in the endothelium of adult mice. More than 90% of mice developed lung hemorrhages and respiratory insufficiency and died by 6-7 wk after gene expression began. Vascular casting and fluorescent microsphere analysis showed evidence of lung AV shunts in affected mice. Cessation of Notch4* expression reversed these pathophysiological effects. Assessment of the vascular morphology revealed enlarged, tortuous vessels in the lungs that resembled arteriovenous malformations. By using whole lung organ culture, we demonstrated the effects of constitutively active Notch4 on the lung vasculature to be a primary lung phenomenon. Together, our results indicate the importance of Notch signaling in maintaining the lung vasculature and offer a new, reliable model with which to study the pathobiology of lung arteriovenous shunts and malformations.

Pulmonary manifestations of liver diseases

Respiratory problems are common in patients with chronic liver diseases. The most common causes are disorders that are not related to liver diseases such as asthma and COPD. In addition certain liver diseases that are associated with specific pulmonary abnormalities, and conditions associated with end stage liver disease like tense ascites and intercostal muscular wasting are considered. Finally two unique disorders characterizing by vascular abnormalities independent of cardiorespiratory disorder-the hepatopulmonary syndrome (HPS) and portopulmonary hypertension (POPH) are observed. These disorders have different pathogenesis, different clinical pictures, treatment and prognosis. This article reviews the epidemiology, pathophysiology, clinical features, evaluation and current therapy of these two disorders.

Saline contrast echocardiography in patients with hepatopulmonary syndrome awaiting liver transplantation

BACKGROUND

Patients with hepatopulmonary syndrome (HPS) with end-stage liver disease (ESLD) have higher cardiorespiratory mortality than those without. The aims of this study were to determine whether echocardiography could distinguish patients with ESLD with and without HPS and whether the diagnosis of HPS by contrast echocardiography (CE) was altered by the performance of the test in a supine or standing position.

METHODS

Subjects were recruited prospectively from patients with end-stage liver disease undergoing assessment for liver transplantation. Hepatopulmonary syndrome was diagnosed on the basis of arterial blood gas analysis, lung function testing and agitated saline contrast echocardiography in the absence of primary cardiac or pulmonary disease. Bubble contrast injections were performed supine or standing in a randomised order and read by a blinded observer.

RESULTS

CE showed late right-to-left shunting in 13 of 50 consecutive patients with cirrhosis (26%). Eight patients (16%) had definite diagnoses of HPS. CE in the standing position consistently increased both the number and the size of shunts compared with supine injection. CE detected intrapulmonary shunting before a change in arterial blood gases. Standard echocardiographic parameters did not distinguish between those with and without HPS.

CONCLUSION

This study suggests that screening for HPS in patients with advanced cirrhosis should be done using CE with patients in the upright position.

Pilot study of pentoxifylline in hepatopulmonary syndrome

Hepatopulmonary syndrome (HPS) results when chronic liver disease or portal hypertension causes intrapulmonary microvascular dilatation with hypoxemia. In experimental HPS, tumor necrosis factor alpha (TNF-alpha) overproduction contributes to vasodilatation, which is improved by pentoxifylline, a TNF-alpha inhibitor. The effectiveness of pentoxifylline in humans is unknown. The aim of this open-label, single-arm clinical trial was to assess the efficacy and tolerability of pentoxifylline in patients with cirrhosis and advanced HPS undergoing liver transplantation evaluation. Nine adults with cirrhosis and moderate to severe HPS were enrolled. All patients had an initial 2-week titration to a target dose of pentoxifylline of 400 mg by mouth every 8 hours, which was continued for 6 weeks. Baseline and follow-up arterial blood gases and TNF-alpha levels were evaluated. Adverse effects and tolerability were assessed. The 9 patients had a mean age of 55 +/- 10 years, and 67% were female. The most common causes of cirrhosis were hepatitis C virus and alcohol (55%). The mean Model for End-Stage Liver Disease score was 11 (range, 6-19), and patients had advanced hypoxemia [mean partial pressure of arterial oxygen (PaO(2)) = 54 +/- 12 mm Hg, mean alveolar-arterial oxygen gradient (A-a PaO(2)) = 57 +/- 15 mm Hg]. Of the 9 patients enrolled, follow-up blood gases were done in 7. There was no significant change in PaO(2) (P = 0.3) or A-a PaO(2) (P = 0.3) with treatment. Pentoxifylline was poorly tolerated. Nausea (100%) and vomiting (56%) were the predominant side effects, and only a single patient was able to complete full-dose therapy. Treatment with pentoxifylline did not improve arterial oxygenation in advanced HPS, and tolerance was limited by gastrointestinal toxicity.

Current concepts in the management of hepatopulmonary syndrome

The hepatopulmonary syndrome is characterized as the triad of liver disease, pulmonary gas exchange abnormalities leading to arterial deoxygenation and evidence of intrapulmonary vascular dilatations. This review summarizes the pathological mechanisms leading to pulmonary vascular changes in hepatopulmonary syndrome. The role of the three currently used diagnostic imaging modalities of contrast-enhanced echocardiography, perfusion lung scanning and pulmonary arteriography that identify the presence of intrapulmonary vascular abnormalities are reviewed. Liver transplantation is considered to be the definitive treatment of hepatopulmonary syndrome with often successful reversal of hypoxemia, however other treatments have been trialed. This review further appraises the evidence for the use of pharmacological agents and the role of radiological interventions in hepatopulmonary syndrome.

Inhaled iloprost for hepatopulmonary syndrome: improvement of hypoxemia

Hepatopulmonary syndrome is characterized by advanced liver disease, hypoxemia, and intrapulmonary shunting. The only reported curative option is orthotopic liver transplantation. We describe here a beneficial effect of inhaled prostacyclin including a decrease in respiratory symptoms and improved oxygenation in this clinical situation, with no approved pharmacological long-term therapy. The prostanoid iloprost, approved for pulmonary and portopulmonary hypertension, caused an increase in oxygenation, relief of dyspnea, and increased exercise tolerance in a patient suffering from liver-cirrhosis-associated hepatopulmonary syndrome. After liver transplantation, restitution of hepatopulmonary syndrome did not occur immediately. Inhaling iloprost resulted in improved physical condition and better clinical rehabilitation potential until hypoxemia finally resolved 3 months after transplantation. Therefore, iloprost could improve quality of life in patients with hepatopulmonary syndrome waiting for liver transplantation and post surgery until the resolution of the hypoxemia.

Resolution of hepatopulmonary syndrome after auxiliary partial orthotopic liver transplantation in Abernethy malformation. A case report

Congenital absence of portal vein and extrahepatic portocaval shunt, also referred to as an Abernethy type 1, is a rare malformation of the mesenteric vasculature. A 9-year-old girl presented with dyspnea on exertion and orthodeoxia. A diagnosis of an Abernethy malformation type 1b and hepatopulmonary syndrome (HPS) was made, and she underwent auxiliary partial orthotopic liver transplantation (APOLT). Symptoms and signs of HPS resolved 2 months after the operation. HPS in Abernethy syndrome is a manifestation of normal portal blood flow bypassing the liver and can be ameliorated by redirecting blood flow to a segment of liver with normal portal anatomy. APOLT is a feasible and successful surgical procedure for patients with Abernethy malformation and HPS.

Hepatopulmonary syndrome

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

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

Background

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

Methods

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

Results

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

Conclusion

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

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

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

Hepatopulmonary syndrome

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

[Hepatopulmonary syndrome: relationship with liver dysfunction and systemic hemodynamic disorder]

BACKGROUND AND OBJECTIVE

The hepatopulmonary syndrome (HPS) causes an increased alveolar to arterial gradient of oxygen and in advanced phases hypoxemia, as the result of pulmonary vasodilation. In liver cirrhosis, it has been demonstrated the existence of splachnic vasodilation and also in other vascular beds. Our main objectives were to know the hemodynamic status, the renal function and the condition of some humoral systems in patient diagnosed of HPS.

PATIENTS AND METHOD

We studied consecutively 32 cirrhotic patients Divided in two groups, a group of 18 cirrhotic patients with normal gaseous exchange (NGE), and another group of 14 cirrhotic patients diagnosed of HPS by contrast-enhanced transthoracic echocardiography and/or lung and brain scintigraphy with 99Tc albumin macroaggregates. They were all in rest in bed, upon alcohol and tobacco abstinence and on a diet of 50 mEq of sodium. Cardiovascular drugs were all withheld during 4 days in order to reach steady state.

RESULTS

Patients of the HPS group were characterized by a more advanced index of Child-Pugh and presence of clubbing and vascular spiders. They presented a greater degree of hypoxemia in a sitting position, greater hypocapnia and smaller transference factor values (TLCO). They also showed a hyperkinetic circulatory condition characterized by smaller arterial blood pressure, greater cardiac index, smaller vascular resistances and greater femoral flows, with smaller clearance of creatinine, elimination of urinary sodium, urinary volume/24 h and an increased plasmatic volume, accompanied with a greater activation of the renin-angiotensin-aldosterone axis and a greater urinary elimination of nitrites and nitrates.

CONCLUSIONS

The pulmonary vasodilation that explains the HPS is a constitutive part of the systemic vasodilation occurring in liver cirrhosis, and it is related to the degree of liver dysfunction as measured by the classification of Child-Pugh. The greater activation of the renin-aldosterone system and the rise of the plasmatic volume express a highest grade of arterial underfilling caused by an increment in the nitric oxide production.

Development of hepatopulmonary syndrome and portopulmonary hypertension in a paediatric liver transplant patient

BACKGROUND

Hepatopulmonary syndrome (HPS) and portopulmonary hypertension (PPH) are pulmonary vascular disorders which occur in patients with severe liver disease and/or portal hypertension. Although these syndromes are frequently diagnosed in patients undergoing assessment for liver transplantation, they seldom occur in the same patient.

METHOD

This report describes a female paediatric patient, born with extra-hepatic biliary atresia, who required liver transplantation, at the age of 15, for secondary biliary cirrhosis. She had severe HPS prior to her first liver transplant, which resolved rapidly following surgery, as well as indirect evidence for PPH. She required a second liver transplant 1 yr later for chronic rejection. Whilst evaluating the patient for a third liver transplant, 4 yr later, severe PPH was discovered. The patient died 3 months later from right heart failure.

CONCLUSION

HPS and PPH may coexist however they may show differing responses to liver transplantation with progression of PPH despite the resolution of HPS.

Síndrome hepatopulmonar: patogenia, diagnóstico e tratamento

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

Hepatopulmonary syndrome

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

The biological "scrabble" of pulmonary arteriovenous malformations: considerations in the setting of cavopulmonary surgery

Pulmonary arteriovenous fistulas are vascular malformations, which, by virtue of producing abnormal vascular connections proximal to the units of gas exchange, result in intrapulmonary right-to-left shunting. These malformations or fistulas reflect at least in part disordered angiogenesis, and less commonly recruitment and dilation of pre-existing vascular channels. Pulmonary arteriovenous fistulas occur in a number of diverse clinical settings. Such fistulas are a well-established feature of the Weber-Osler-Rendu complex, or hereditary haemorrhagic telangiectasia, an autosomal dominant vascular dysplasia characterized by mucocutaneous telangiectasis, epistaxis, gastrointestinal haemorrhage, and arteriovenous malformations in the lung, brain, liver and elsewhere. They are also seen in the patient with acute or chronic liver disease, disease that is usually but not invariably severe, or those with non-cirrhotic portal hypertension. They may occur as congenital malformations, single or diffuse, large or small in isolation, and when large or extensive enough may result in hypoxaemia, clinical cyanosis, and heart failure. Cerebral vascular accidents are also a well-known complication of this disorder. An extensive literature has accumulated with regard to the pulmonary arteriovenous fistulas seen in the setting of the Weber-Osler-Rendu complex, and there is considerable information on the genetics, basic biology, clinical findings, complications and therapeutic interventions of these malformations in the setting of this syndrome. These issues, however, are not the primary considerations of this review, although some aspects of this fascinating disorder will be discussed later. Rather the focus will be on pulmonary arteriovenous malformations that develop in the setting of cavopulmonary surgery, and their relationship to the pulmonary arteriovenous fistulas occurring in the hepatopulmonary syndrome. The complex tapestry of these overlapping and intersecting clinical observations will be unfolded in the light of their chronology.

Frequency, clinical characteristics, and respiratory parameters of hepatopulmonary syndrome

OBJECTIVES

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Liver transplantation for hepatopulmonary syndrome: a ten-year experience in Paris, France

BACKGROUND

Although the possibility of reversing hepatopulmonary syndrome (HPS) after liver transplantation is now well established, the proportion of patients in whom reversibility is observed and the time to resolution of HPS remain uncertain.

METHODS

We analyzed the outcome of all adult patients with HPS who underwent orthotopic liver transplantation in all the liver transplant centers in Paris, during a 10-year period.

RESULTS

Twenty-three adult patients (median age, 47 years; range, 14-64) underwent transplantation in four institutions. Median PaO(2) was 52 (range, 32-67) mm Hg and median alveolar-arterial oxygen gradient was 66 mm Hg. When patients were breathing 100% O(2), median PaO(2) was 310 (range, 74-663) mm Hg. Median isotopic shunt ratio was 33% (range, 0-80%). The overall mortality during the study period was 30.5% (7/23). Perioperative mortality was 8.5%, whereas late mortality was 22%. None of the preoperative characteristics of HPS (isotopic shunt ratio, PaO(2) on room air or on 100% oxygen) was associated with overall postoperative mortality. Of the 21 patients surviving the perioperative period (median follow-up, 17 months; range, 0.5-72), a decrease in alveolar-arterial oxygen gradient of at least 5 mm Hg and at least 10 mm Hg was observed in 21 of 21 and in 18 of 21 patients, respectively, with great variations in the time of improvement. The threshold of 70 mm Hg was reached in 15 patients. The lower the preoperative PaO(2), the longer the time to reach this point.

CONCLUSION

Our data strongly support the role of orthotopic liver transplantation in adult patients with HPS, regardless of its severity.