Mediators, cytokines, and growth factors in liver-lung interactions

Cardiac risk stratification of the liver transplant candidate: A comprehensive review

Cardiovascular diseases (CVD) form a principal consideration in patients with end-stage liver disease (ESLD) undergoing evaluation for liver transplant (LT) with prognostic implications in the peri- and post-transplant periods. As the predominant etiology of ESLD continues to evolve, addressing CVD in these patients has become increasingly relevant. Likewise, as the number of LTs increase by the year, the proportion of older adults on the waiting list with competing comorbidities increase, and the demographics of LT candidates evolve with parallel increases in their CVD risk profiles. The primary goal of cardiac risk assessment is to preemptively reduce the risk of cardiovascular morbidity and mortality that may arise from hemodynamic stress in the peri- and post-transplant periods. The complex hemodynamics shared by ESLD patients in the pre-transplant period with adverse cardiovascular events occurring in only some of these recipients continue to challenge currently available guidelines and their uniform applicability. This review focusses on cardiac assessment of LT candidates in a stepwise manner with special emphasis on preoperative patient optimization. We hope that this will reinforce the importance of cardiovascular optimization prior to LT, prevent futile LT in those with advanced CVD beyond the stage of optimization, and thereby use the finite resources prudently.

Portopulmonary Hypertension: A Review of the Current Literature

Portopulmonary hypertension is defined as the development of pulmonary arterial hypertension in the setting of portal hypertension with or without liver cirrhosis. Portal hypertension-associated haemodynamic changes, including hyperdynamic state, portosystemic shunts and splanchnic vasodilation, induce significant alterations in pulmonary vascular bed and play a pivotal role in the pathogenesis of the disease. If left untreated, portopulmonary hypertension results in progressive right heart failure, with a poor prognosis. Although Doppler echocardiography is the best initial screening tool for symptomatic patients and liver transplantation candidates, right heart catheterisation remains the gold standard for the diagnosis of the disease. Severe portopulmonary hypertension exerts a prohibitive risk to liver transplantation by conferring an elevated perioperative mortality risk. It is important for haemodynamic parameters to correspond with non-severe portopulmonary hypertension before patients can proceed with the liver transplantation. Small uncontrolled studies and a recent randomised controlled trial have reported promising results with vasodilatory therapies in clinical and haemodynamic improvement of patients, allowing a proportion of patients to undergo liver transplantation. In this review, the epidemiology, pathogenesis, diagnostic approach and management of portopulmonary hypertension are discussed. We also highlight fields of ongoing investigation pertinent to risk stratification and optimal patient selection to maximise long-term benefit from currently available treatments.

Hepatoma-derived growth factor is associated with pulmonary vascular remodeling and PAH disease severity and survival

Hepatoma-derived growth factor (HDGF) was previously shown to be associated with increased mortality in a small study of idiopathic and connective tissue disease-associated pulmonary arterial hypertension (PAH). In this study, we measured serum HDGF levels in a large multicenter cohort (total 2017 adult PAH-Biobank enrollees), we analyzed the associations between HDGF levels and various clinical measures using linear or logistic regression models. Higher HDGF levels were found to be significantly associated with worse pulmonary hemodynamics, prostacyclin treatment; among PAH subtypes, higher HDGF levels were most associated with portopulmonary hypertension (beta = 0.469, p < 0.0001). Both Kaplan-Meier curve and Cox proportional hazard regression demonstrated that higher HDGF levels are associated with a higher risk of mortality (COX hazard ratio 1.31, p < 0.0001). Further, in the Sugen hypoxia (SuHx) rat model, the highest HDGF levels were post-pulmonary circulation, and HDGF levels significantly increased with the development of PAH. In pulmonary arteries, immunohistochemistry staining showed that HDGF was highly expressed in pulmonary smooth muscle cells in both PAH patients and SuHx rats. In conclusion, we found that higher serum HDGF was linked with increased mortality, and associated with disease severity in a large multi-center adult PAH cohort (n = 2017). In the SuHX PAH models, circulating HDGF levels are pulmonary in origin and increase with PAH progression. HDGF may be actively involved in vascular remodeling in PAH.

Liver-lung interactions in acute respiratory distress syndrome

Patients with liver diseases are at high risk for the development of acute respiratory distress syndrome (ARDS). The liver is an important organ that regulates a complex network of mediators and modulates organ interactions during inflammatory disorders. Liver function is increasingly recognized as a critical determinant of the pathogenesis and resolution of ARDS, significantly influencing the prognosis of these patients. The liver plays a central role in the synthesis of proteins, metabolism of toxins and drugs, and in the modulation of immunity and host defense. However, the tools for assessing liver function are limited in the clinical setting, and patients with liver diseases are frequently excluded from clinical studies of ARDS. Therefore, the mechanisms by which the liver participates in the pathogenesis of acute lung injury are not totally understood. Several functions of the liver, including endotoxin and bacterial clearance, release and clearance of pro-inflammatory cytokines and eicosanoids, and synthesis of acute-phase proteins can modulate lung injury in the setting of sepsis and other severe inflammatory diseases. In this review, we summarized clinical and experimental support for the notion that the liver critically regulates systemic and pulmonary responses following inflammatory insults. Although promoting inflammation can be detrimental in the context of acute lung injury, the liver response to an inflammatory insult is also pro-defense and pro-survival. A better understanding of the liver–lung axis will provide valuable insights into new diagnostic targets and therapeutic strategies for clinical intervention in patients with or at risk for ARDS.

Vascular syndromes in liver cirrhosis

Liver cirrhosis is associated with multiple vascular syndromes affecting almost all body systems. Many of these syndromes are directly related to impaired liver function and sometimes reversible after liver transplantation while others arise secondary to portal hypertension and ascites. Altered expression of angiogenic and vasoactive compounds (most importantly nitric oxide), endothelial dysfunction, dysregulated neurohormonal control, and systemic inflammatory state play differential roles in mediating homeostatic instability and abnormal vasogenic response. Important vascular features encountered in liver disease include portal hypertension, splanchnic overflow, abnormal angiogenesis and shunts, portopulmonary syndrome, hepatopulmonary syndrome, and systemic hyperdynamic circulation. Redistribution of effective circulatory volume deviating from vital organs and pooling in splanchnic circulation is also encountered in liver patients which may lead to devastating outcomes as hepatorenal syndrome. Etiologically, vascular syndromes are not isolated phenomena and vascular dysfunction in one system may lead to the development of another in a different system. This review focuses on understanding the pathophysiological factors underlying vascular syndromes related to chronic liver disease and the potential links among them. Many of these syndromes are associated with high mortality, thus it is crucial to look for early biomarkers for these syndromes and develop novel preventive and therapeutic strategies.

Acute-on-chronic liver failure in chronic hepatitis B: an update

Acute-on-chronic liver failure is a common pattern of end-stage liver disease in clinical practice and occurs frequently in patients with chronic hepatitis B or HBV-related cirrhosis. New progress in recent years leads to a better understanding of this disease. Areas covered: This review updates the current comprehensive knowledge about HBV-ACLF from epidemiological studies, experimental studies, and clinical studies and provide new insights into the definition, diagnostic criteria, epidemiology, nature history, pathogenesis, treatment and prognostication of HBV-ACLF. Expert commentary: Patients with chronic hepatitis B or HBV-related cirrhosis are at risk of developing acute-on-chronic liver failure, with multi-organ failure and high short-term mortality. The precipitating events can be intra-hepatic or extra-hepatic and the underlying chronic liver injury can be cirrhotic or non-cirrhotic. Host and viral factors contribute to the susceptibility of developing HBV-ACLF. Systemic inflammation is the driver of HBV-ACLF, which can be attributed to non-sterile and sterile factors. Liver transplantation is the definitive treatment for HBV-ACLF. Cell therapy is a promising alternative to LT, but requires validation and still has concern of long-term safety. Other medical therapies, such as nucleoside analogue, artificial liver supporting and glucocorticoid may improve survival in a specific subgroup. New scoring systems improve the accuracy of prognostication in HBV-ACLF, which is critical for early identification of candidates for LT.

Impact of Bacterial Translocation on Hepatopulmonary Syndrome: A Prospective Observational Study

BACKGROUND/AIMS

Hepatopulmonary syndrome (HPS) is characterized by a defect in oxygenation induced by pulmonary vascular dilatation in cirrhosis. While severe HPS is responsible for a high rate of mortality, the prevalence and pathophysiology of HPS are not fully elucidated. We evaluated the prevalence and pathophysiology of HPS in patients with cirrhosis.

METHODS

A total of 142 patients with cirrhosis who underwent saline-agitated contrast echocardiography were enrolled in this prospective observational study. HPS was defined by positive findings on contrast echocardiography, cirrhosis, and the presence of an oxygenation defect (alveolar-arterial oxygen gradient > 15 mmHg). HPS grades from 0 to 3 were assigned based on the density and spatial distribution of microbubbles in the left ventricle. The primary endpoint was the prevalence of HPS. The secondary endpoints included clinical characteristics and levels of lipopolysaccharide (LPS), LPS-binding protein (LBP), nitric oxide, and endothelin-1 in HPS.

RESULTS

Fifty-nine patients (41.5%) were diagnosed with HPS (grade 1: 24, grade 2: 23, and grade 3: 12 patients). The mean levels of LPS (0.36 ± 0.02, 1.02 ± 0.18, 2.86 ± 0.77, and 6.56 ± 1.46 EU/mL, p < 0.001) and LBP (7026 ± 3336, 11,445 ± 1247, 11,947 ± 1164, and 13,791 ± 2032 ng/mL, p = 0.045) were found to be increased according to HPS grade (negative, grade 1-3). Endothelin-1 levels were significantly elevated according to HPS grade (1.83 ± 0.17, 2.62 ± 0.22, 3.69 ± 0.28, and 4.29 ± 0.34 pg/mL, p < 0.001), demonstrating a significant difference between each grade (p < 0.05).

CONCLUSIONS

HPS is a common complication with a prevalence of 41.5% in patients with cirrhosis. Bacterial translocation and portal pulmonary vascular dilatation are key mechanism involved in the progression of HPS.

Optimal management of pulmonary arterial hypertension: prognostic indicators to determine treatment course

Pulmonary arterial hypertension (PAH) is a rapidly progressive pulmonary vascular disease with a multifactorial etiopathogenesis that can result in right-sided heart failure and death. A number of studies indicate that an early therapeutic intervention yields better results on disease progression as compared to delayed treatment. In this review, we will analyze treatment strategies that may be used for monitoring disease progression and for guiding treatment decisions. Several factors (ie, symptoms, functional class, exercise capacity as assessed by a walking test and cardiopulmonary stress testing, hemodynamic parameters, cardiac magnetic resonance imaging, and plasma levels of biochemical markers) have been prognostic of survival. These indicators may be used both at the time of diagnosis and during treatment follow-up. No resolutive therapy is currently available for PAH; however, in the last decade, the advent of specific pharmacological treatments has given new hope to patients suffering from this debilitating disease with a poor prognosis. Combination drug therapies offer increased benefits over monotherapy, and current guidelines recommend a sequential “add on” design approach for patients in functional class II–IV. The goal-oriented “treat to target” therapy sets the timing for treatment escalation in case of inadequate response to currently known prognostic indicators. To date, further longitudinal studies should be urgently conducted to identify new goals that may improve therapeutic strategies in order to optimize personalized treatment in PAH patients.

Beyond a broken heart: circulatory dysfunction in the failing Fontan

The role of ventricular dysfunction in late morbidity and mortality of univentricular hearts has been described previously. However, a significant proportion of adult Fontan patients who die or require heart transplantation do so with preserved ventricular function. The clinical deterioration in patients who have undergone Fontan palliation requires a broader view of circulatory dysfunction, one that takes into account the complex interaction of regulatory systems affecting hepatic, renal, and pulmonary blood flow, in addition to cardiac function. This review focuses primarily on the pathophysiology of multiple organ involvement in this circulatory dysfunction, with particular focus on the consequences of hepatic dysfunction and portal hypertension. The authors discuss hepatic perfusion, both in health and disease, and review the current understanding of liver histopathology and liver disease in adult Fontan patients and similar clinicopathologic states. They compare and contrast features of postsinusoidal portal hypertension with more typical adult cirrhotic disease. Finally, they delineate the related effects of portal hypertensive physiology on the systemic and pulmonary vasculature, the kidney, and the heart itself and discuss how these changes affect the care of the adult Fontan patient.

Pharmacological treatment for hepatopulmonary syndrome

AIM

Hepatopulmonary syndrome is a pulmonary dysfunction in the context of liver cirrhosis characterized by arterial deoxygenation. Affected patients have increased morbidity and mortality, and many of them expire before undergoing liver transplantation. Therefore, finding medical therapy as a bridge to transplantation or as a final treatment is necessary. In this study, we aimed to review the current literature about pharmacological options available for treatment of hepatopulmonary syndrome.

METHODS

A PubMED and Scopus search was conducted in January 2013 on the English literature published in any time period to find human and animal studies reporting pharmacological therapy of hepatopulmonary syndrome.

RESULTS

Out of 451 studies, 29 relevant articles were included. The number of patients, type, dose, duration, and mechanism of drugs in these studies was extracted and summarized separately. Most of pharmacologic agents act through inhibition of nitric oxide synthase and reduction in nitric oxide production, inactivation of endothelin-1, and treatment of bacterial translocation and pulmonary angiogenesis.

CONCLUSION

Several drugs have been applied for the treatment of HPS with conflicting results. However, no large randomized trial has been conducted probably due to low number of patients. Multicentered clinical trials are necessary to investigate these drugs.

Liver in cardiopulmonary disease

Hepatopulmonary syndrome (HPS) and portopulmonary hypertension (PoPH) are two fascinating and incompletely understood pulmonary vascular conditions seen in the setting of cirrhotic patients. Of the two HPS is more common and is primarily caused by pulmonary vasodilatation resulting in hypoxaemia and hyperdynamic circulation. PoPH is less common and conversely, pulmonary vasoconstriction and vascular remodelling occurs resulting in increased pulmonary vascular resistance. However, both conditions can co-exist and it is usually PoPH which develops in a patient with pre-existing HPS. Although these two pulmonary conditions are not common complications of chronic liver diseases, the treatment options are mainly limited to liver transplantation. Cirrhotic cardiomyopathy is closely related to haemodynamic changes in portal hypertension. The key features are normal cardiac pressures at rest, with reduced ability to compensate for physiological or iatrogenic stresses such as drug therapy or TIPSS. There is no effective therapy and outcomes after liver transplantation are variable.

Pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a chronic and progressive disease leading to right heart failure and ultimately death if untreated. The first classification of PH was proposed in 1973. In 2008, the fourth World Symposium on PH held in Dana Point (California, USA) revised previous classifications. Currently, PH is devided into five subgroups. Group 1 includes patients suffering from idiopathic or familial PAH with or without germline mutations. Patients with a diagnosis of PAH should systematically been screened regarding to underlying mutations of BMPR2 gene (bone morphogenetic protein receptor type 2) or more rarely of ACVRL1 (activine receptor-like kinase type 1), ENG (endogline) or Smad8 genes. Pulmonary veno occusive disease and pulmonary capillary hemagiomatosis are individualized and designated as clinical group 1'. Group 2 'Pulmonary hypertension due to left heart diseases' is divided into three sub-groups: systolic dysfonction, diastolic dysfonction and valvular dysfonction. Group 3 'Pulmonary hypertension due to respiratory diseases' includes a heterogenous subgroup of respiratory diseases like PH due to pulmonary fibrosis, COPD, lung emphysema or interstitial lung disease for exemple. Group 4 includes chronic thromboembolic pulmonary hypertension without any distinction of proximal or distal forms. Group 5 regroup PH patients with unclear multifactorial mechanisms. Invasive hemodynamic assessment with right heart catheterization is requested to confirm the definite diagnosis of PH showing a resting mean pulmonary artery pressure (mPAP) of ≥ 25 mmHg and a normal pulmonary capillary wedge pressure (PCWP) of ≤ 15 mmHg. The assessment of PCWP may allow the distinction between pre-capillary and post-capillary PH (PCWP > 15 mmHg). Echocardiography is an important tool in the management of patients with underlying suspicion of PH. The European Society of Cardiology and the European Respiratory Society (ESC-ERS) guidelines specify its role, essentially in the screening proposing criteria for estimating the presence of PH mainly based on tricuspid regurgitation peak velocity and systolic artery pressure (sPAP). The therapy of PAH consists of non-specific drugs including oral anticoagulation and diuretics as well as PAH specific therapy. Diuretics are one of the most important treatment in the setting of PH because right heart failure leads to fluid retention, hepatic congestion, ascites and peripheral edema. Current recommendations propose oral anticoagulation aiming for targeting an International Normalized Ratio (INR) between 1.5-2.5. Target INR for patients displaying chronic thromboembolic PH is between 2–3. Better understanding in pathophysiological mechanisms of PH over the past quarter of a century has led to the development of medical therapeutics, even though no cure for PAH exists. Several specific therapeutic agents were developed for the medical management of PAH including prostanoids (epoprostenol, trepoprostenil, iloprost), endothelin receptor antagonists (bosentan, ambrisentan) and phosphodiesterase type 5 inhibitors (sildenafil, tadalafil). This review discusses the current state of art regarding to epidemiologic aspects of PH, diagnostic approaches and the current classification of PH. In addition, currently available specific PAH therapy is discussed as well as future treatments.

Review article: liver transplantation for the pulmonary disorders of portal hypertension

BACKGROUND

Liver transplantation is potentially a life-saving therapeutic intervention for patients with portopulmonary hypertension and hepatopulmonary syndrome. However, due to limited data, listing criteria for patients with these conditions have not been clearly established. Indeed, this has led some to speculate that transplantation may not be appropriate in cases of moderate-to-severe portopulmonary hypertension and severe hepatopulmonary syndrome.

AIM

To critically discuss the utility of LT for the treatment of hepatopulmonary syndrome and portopulmonary hypertension.

METHODS

A literature search was conducted in 2012 on PubMed, Ovid Embase, Ovid Medline and Scopus using the following search terms: hepatopulmonary syndrome, portopulmonary hypertension, pulmonary arterial hypertension, liver transplantation. Relevant manuscripts were included in the review.

RESULTS

Liver transplantation has established itself as an effective treatment for selected patients with hepatopulmonary syndrome and portopulmonary hypertension. A multidisciplinary team approach incorporating focused strategies (both pre- and post-operatively) aimed at improving oxygenation in patients with hepatopulmonary syndrome has led to a dramatic improvement in patient outcomes. Additionally, careful patient selection and the use of targeted pulmonary vascular therapies are successfully being used to treat portopulmonary hypertension and 'bridge' patients to successful liver transplantation.

CONCLUSIONS

Liver transplantation is an effective therapy for patients with hepatopulmonary syndrome and portopulmonary hypertension. However, rigorous screening and early identification of these conditions allied with aggressive pre-operative optimisation of physiology and diligent post-operative care are imperative to ensuring a good outcome.

Pentoxifylline in hepatopulmonary syndrome

AIM: To determine the effects of pentoxifylline (PTX) on clinical manifestations and evaluate arterial blood gas data in hepatopulmonary syndrome (HPS) in children.

METHODS: In a pilot study of 10 children with chronic liver disease, who had HPS, 20 mg/kg/d PTX was administered for 3 mo. Clinical data and arterial blood gas parameters were evaluated at baseline, the end of the treatment period, and 3 mo after drug discontinuation.

RESULTS: Six patients could tolerate PTX, while four patients experienced complications. Among patients who could tolerate PTX, there was a significant increase in arterial oxygen pressure (PaO₂) (P = 0.02) and oxygen saturation (SaO₂) (P = 0.04) and alveolar-arterial oxygen gradient (P = 0.02) after 3 mo of treatment. Significant decreases in PaO₂ (P = 0.02) and alveolar-arterial oxygen gradient (P = 0.02) were also seen after drug discontinuation.

CONCLUSION: PTX may improve PaO₂, SaO₂ and alveolar-arterial oxygen gradient in the early stage of HPS.

Clinical manifestations of portal hypertension

The portal hypertension is responsible for many of the manifestations of liver cirrhosis. Some of these complications are the direct consequences of portal hypertension, such as gastrointestinal bleeding from ruptured gastroesophageal varices and from portal hypertensive gastropathy and colopathy, ascites and hepatorenal syndrome, and hypersplenism. In other complications, portal hypertension plays a key role, although it is not the only pathophysiological factor in their development. These include spontaneous bacterial peritonitis, hepatic encephalopathy, cirrhotic cardiomyopathy, hepatopulmonary syndrome, and portopulmonary hypertension.

Portopulmonary hypertension and serum endothelin levels in hospitalized patients with cirrhosis

BACKGROUND

Cirrhosis is associated with several extrahepatic manifestations including portopulmonary hypertension (PPHT). Recent data suggest that endothelins (ETs) are related to the pathophysiology of PPHT. The study aimed to measure serum ET levels in hospitalized cirrhotic patients and to determine their association with PPHT and patient outcome.

METHODS

Fifty-seven cirrhotic patients [43 males; median age 58 (28-87) years] underwent Doppler echocardiography. Patients with systolic pulmonary arterial pressure ≥40 mmHg and pulmonary acceleration time <100 ms were deemed to have PPHT. ET-1, 2, and 3 serum levels were measured with an ELISA assay. All-cause mortality was recorded over a median period of 24 months.

RESULTS

Nine out of 57 patients (15.8%) had PPHT. Among various clinical variables, only autoimmune hepatitis was associated with PPHT (OR=11.5; 95% CI, 1.58-83.4; P=0.01). ET-1 levels [9.1 (1.6-20.7) vs 2.5 (1.4-9.2) pg/mL, P=0.02] and the ET-1/ET-3 ratio [4.73 (0.9-22.4) vs 1.6 (0.3-10.7), P=0.02] were significantly higher in patients with PPHT than in those without. ET-2 and ET-3 levels did not differ between the two groups. There was no difference in survival between the two groups, although ET-1 levels were associated with an adverse outcome in Cox regression analysis (HR=1.11; 95% CI, 1.02-1.22; P=0.02 per unit increase in ET-1).

CONCLUSION

Our data suggest that ET-1 and the ET-1/ET-3 ratio are elevated in patients with PPHT and that ET-1 is associated with a poor outcome irrespective of PPHT.

Risk factors and mortality associated with an elevated tricuspid regurgitant jet velocity measured by Doppler-echocardiography in thalassemia: a Thalassemia Clinical Research Network report

An elevated tricuspid regurgitant jet velocity (TRV) is associated with hemolysis and early mortality in sickle cell disease, yet risk factors, clinical parameters, and mortality associated with this biomarker in thalassemia are poorly defined. This report summarizes the prevalence of an elevated TRV in 325 patients screened by Doppler echocardiography in the Thalassemia Clinical Research Network. A documented TRV was reported in 148 of 325 (46%) of patients. Average age was 25.9 years (range, 5-56 years) and 97% were transfusion-dependent. Mean TRV was 2.3 ± 0.4 m/s (range, 0.2-3.5 m/s). An abnormal TRV ≥ 2.5 m/s was identified in 49 of 148 (33%) of patients with a documented TRV, 5% (8/148), with a TRV ≥ 3.0 m/s, suggesting significant PH risk. Older age was strongly associated with a high TRV; however, 16% of children had a TRV ≥ 2.5 m/s. A history of splenectomy, hepatitis C, smoking, or high white blood cell count was associated with TRV elevation. In summary, an elevated TRV is noted in one-third of transfusion-dependent thalassemia patients with a documented value and develops in both children and adults. Age, splenectomy, hepatitis C, and smoking are significant univariate risk factors, with splenectomy surfacing as the dominant risk factor over time. Mortality was low in this cohort. Prospective longitudinal studies are needed. This study is registered at http://www.clinicaltrials.gov as NCT00661804.

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.

Portopulmonary hypertension: challenges in diagnosis and management

Portopulmonary hypertension is defined as the combination of pulmonary arterial hypertension with portal hypertension and presents management complications in patients awaiting liver transplantation. The combination of these vascular disorders has a marked impact on mortality. At present the recommendations for management are limited because of the paucity of definitive clinical trials. We have reviewed the available data on prevalence, diagnosis and treatment. It is clearly time to more formally approach the study of this patient population.

Two Cases of Pulmonary Hypertension Associated with Type III Glycogen Storage Disease

Glycogen storage diseases (GSDs) comprise a large, heterogeneous group of disorders characterized by abnormal glycogen deposition. Multiple cases in the literature have demonstrated an association between GSD type I and pulmonary arterial hypertension (PAH). We now also report on two patients with GSD type III and PAH, a novel association. The first patient was a 16-year-old girl of Nicaraguan descent with a history of hepatomegaly and growth retardation. Molecular testing identified a homozygous 17delAG mutation in AGL consistent with GSD type IIIb. At the age of 16, she was found to have PAH and was started on medical therapy. Two years later, she developed acute chest pain and died shortly thereafter. The second patient is a 13-year-old girl of Colombian descent homozygous for the c.3911dupA mutation consistent with GSD IIIa. An echocardiogram at age 2 showed left ventricular hypertrophy, which resolved following the institution of a high protein, moderate carbohydrate diet during the day and continuous gastric-tube feeding overnight. At the age of 12, she was found to have pulmonary hypertension. She was started on sildenafil, and her clinical status has shown marked improvement including normalization of her elevated transaminases. PAH may be a rare association in patients with GSD IIIa and IIIb and should be evaluated with screening echocardiograms for cardiac hypertrophy or if they present with symptoms of right-sided heart failure such as shortness of breath, chest pain, cyanosis, fatigue, dizziness, syncope, or edema. Early diagnosis of PAH is important as increasingly effective treatments are now available.

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.

Prevalence of hepatic parasites in Korean wild rats (Rattus norvegicus) and their association with pulmonary arteriolar medial hypertrophy

C hepatica, an important zoonotic parasite, and C fasciolaris are common parasites in rodents. In rodent livers, C hepatica causes sequential morphologic changes that are designated as early, intermediate, or late phase, and C fasciolaris forms cysts surrounded by fibroplasia and granulomatous inflammation. The present study describes the prevalence of these parasites and associated liver and lung lesions in wild rats (Rattus norvegicus) living around pig farms in South Korea. Selected parenchymal organs, including liver and lung, of 89 wild rats were examined. Of 89 rats, 28 (31.5%) were infected with either C hepatica or C fasciolaris or with both parasites. Severe medial hypertrophy of small arterioles was observed in the lungs of 11 of the 28 parasite-infected rats (P < .01). The pulmonary arteriolar hypertrophy in the rats infected with C hepatica was strongly associated with early and/or intermediate phases (88.8%) of morphologic change in the livers (P < .01). As such, this report is the first to suggest a significant association between parasite-induced hepatitis and pulmonary arteriolar hypertrophy in rodents. Further studies are warranted for the use of C hepatica-infected rats as an animal model to explore the underlying mechanisms of portopulmonary hypertension in humans.

Pulmonary complications of cirrhosis

Advanced liver disease and portal hypertension produce various intrathoracic complications that involve the pleural space, the lung parenchyma, and the pulmonary circulation. Dyspnea and arterial hypoxemia are the most common symptoms and signs in patients with such complications. This article focuses on the diagnosis and management of hepatopulmonary syndrome, portopulmonary hypertension, and hepatic hydrothorax. All are pulmonary processes associated with end-stage liver disease that lead to significant morbidity and affect the quality of life of patients who are suffering from liver cirrhosis.

Review: Therapeutic advances in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is characterized by vasoconstriction, in situ thrombosis, and vascular remodeling of small pulmonary arteries inducing increased pulmonary arterial resistance. Conventional treatment is based on life style modification and nonspecific treatment (warfarine, diuretics, oxygen). Calcium channel blockers are vasodilatators that have been shown to be of great efficacy in a very specific subpopulation of patients with PAH. For the majority of patients, specific PAH therapies are still lacking. Numerous studies evaluating prostacyclin agonists, endothelin-receptor antagonists, and phosphodiesterase type 5 inhibitors are now available to guide therapeutic choices. Despite those important advances there is still no cure for PAH. Fortunately, research is ongoing and many drugs show promises.

Primary biliary cirrhosis complicated by polymyositis and pulmonary hypertension

A 68-year-old woman was admitted to a hospital with pulmonary hypertension (PH) in August 2006. Perfusion scintigraphy of the lung was normal and showed no interstitial change. Liver dysfunction was noted and antinuclear antibodies (x1,280) were positive. In November 2006, muscle pain and weakness gradually developed in the brachial muscle and a quadriceps. She was referred and admitted to our hospital for elevated CPK and liver dysfunction in March 2007. She was diagnosed with polymyositis (PM) on the basis of the histological findings of muscle biopsy and treated with prednisolone. In addition, because anti-centromere antibodies and anti-mitochondrial M2 antibodies were positive with high titers, she was also diagnosed with primary biliary cirrhosis (PBC). Although PBC is often associated with other autoimmune diseases, there have been no reports of PBC complicated by PM and PH.

Pre- and postoperative systemic hemodynamic evaluation in patients subjected to esophagogastric devascularization plus splenectomy and distal splenorenal shunt: A comparative study in schistomomal portal hypertension

AIM: To investigate the systemic hemodynamic effects of two surgical procedures largely employed for treatment of schistosomal portal hypertension.

METHODS: Thirty-six patients undergoing elective surgical treatment of portal hypertension due to hepatosplenic mansonic schistosomiasis were prospectively evaluated. All patients were subjected to preoperative pulmonary artery catheterization; 17 were submitted to esophagogastric devascularization and splenectomy (EGDS) and 19 to distal splenorenal shunt (DSRS). The systemic hemodynamic assessment was repeated 4 d after the surgical procedure.

RESULTS: Preoperative evaluation revealed (mean ± SD) an increased cardiac index (4.78 ± 1.13 L/min per m²), associated with a reduction in systemic vascular resistance index (1457 ± 380.7 dynes.s/cm⁵.m²). The mean pulmonary artery pressure (18 ± 5.1 mmHg) as well as the right atrial pressure (7.9 ± 2.5 mmHg) were increased, while the pulmonary vascular resistance index (133 ± 62 dynes.s/cm⁵.m²) was decreased. Four days after EGDS, a significant reduction in cardiac index (3.80 ± 0.4 L/min per m², P < 0.001) and increase in systemic vascular resistance index (1901.4 ± 330.2 dynes.s/cm⁵.m², P < 0.001) toward normal levels were observed. There was also a significant reduction in pulmonary artery pressure (12.65 ± 4.7 mmHg, P < 0.001) and no significant changes in the pulmonary vascular resistance index (141.6 ± 102.9 dynes.s/cm⁵.m²). Four days after DSRS, a non-significant increase in cardiac index (5.2 ± 0.76 L/min per m²) and systemic vascular resistance index (1389 ± 311 dynes.s/cm⁵.m²) was observed. There was also a non-significant increase in pulmonary artery pressure (19.84 ± 5.2 mmHg), right cardiac work index (1.38 ± 0.4 kg.m/m²) and right ventricular systolic work index (16.3 ± 6.3 g.m/m²), without significant changes in the pulmonary vascular resistance index (139.7 ± 67.8 dynes.s/cm⁵.m²).

CONCLUSION: The hyperdynamic circulatory state observed in mansonic schistosomiasis was corrected by EGDS, but was maintained in patients who underwent DSRS. Similarly, the elevated mean pulmonary artery pressure was corrected after EGDS and maintained after DSRS. EGDS seems to be the most physiologic surgery for patients with schistosomal portal hypertension.

Clinical differences between children and adults with pulmonary hypertension and sickle cell disease

Pulmonary hypertension (PHT) is an important co-morbidity in sickle cell disease (SCD). Despite increasing research in adults, the prevalence and implication of this condition in children is unknown. Charts of 362 SCD patients followed at the Children's Hospital & Research Center Oakland were reviewed to determine clinical variables associated with obtaining echocardiographic screening for PHT, clinical associations of PHT, and associated mortality following diagnosis in adults and children with SCD. In this cohort, patients with underlying lung abnormalities or those on chronic transfusions were more likely to have echocardiograms, however the diagnosis of PHT was often unrecognized. A different clinical phenotype for PHT in adults versus children was identified. Associations with PHT for adults included age, renal and lung disease, hepatitis C, chronic transfusions, and a history of acute chest syndrome (ACS), with ACS being protective. Surprisingly, for children, a history of sepsis, along with a history of ACS, or obstructive lung disease were associated with PHT. Survival analysis found significant mortality for PHT, with a hazard ratio of 17.3 (95% confidence interval 4.9-60.4). The divergent clinical spectrum for PHT between adults and children may point to different age-specific mechanisms or biological expression of PHT.

Cirrhotic rats with bacterial translocation have higher incidence and severity of hepatopulmonary syndrome

BACKGROUND

Bacterial translocation, that is, extra-intestinal dissemination of gut bacteria, occurs in approximately 50% of humans and rats with cirrhosis and plays a significant role in enhanced tumor necrosis factor-alpha (TNF-alpha) production. The authors' previous studies have indicated that prevention of bacterial translocation with norfloxacine or inhibition of TNF-alpha with pentoxifylline treatment decreased both the incidence and severity of hepatopulmonary syndrome by attenuating the induction of pulmonary intravascular macrophages in cirrhotic rats. In the present study the hypothesis was tested that the cirrhotic rats with bacterial translocation had higher TNF-alpha production, higher level of sequestration of macrophages in pulmonary vessels, and increased incidence and severity of hepatopulmonary syndrome.

METHODS

Rats were studied 5 weeks after common bile duct ligation or sham operation. Bacterial translocation was defined by positive mesenteric lymph node cultures. Hepatopulmonary syndrome was assessed by measurements of alveoloarterial oxygen difference (AaPO(2)) and intrapulmonary shunt. The TNF-alpha concentration in plasma was measured by ELISA. Pulmonary intravascular macrophage sequestration was assessed by lung morphometric analysis.

RESULTS

Bacterial translocation occurred in 48% of cirrhotic rats. Plasma concentrations of TNF-alpha and the percentage of vessels with pulmonary intravascular macrophages were higher in the cirrhotic rats with bacterial translocation. Rats with bacterial translocation also had a higher incidence (9% vs 63%, P < 0.01) and severity of hepatopulmonary syndrome, as indicated by higher levels of both AaPO(2) and intrapulmonary shunt.

CONCLUSIONS

These results suggest that bacterial translocation may play a role in the pathogenesis of hepatopulmonary syndrome by inducing pulmonary intravascular macrophages through TNF-alpha upregulation.

Hipertensão portopulmonar

Hipertensão portal e cirrose podem causar complexas alterações do leito vascular pulmonar, dentre elas a síndrome hepatopulmonar e a hipertensão portopulmonar. A associação de hipertensão pulmonar com cirrose e hipertensão portal é pouco diagnosticada, sendo sua prevalência estimada por volta de 1% a 2% dos pacientes com hipertensão portal ou cirrose, sem preferência por sexo, e com predomínio na faixa dos 40 anos. Fatores etiológicos não foram bem definidos para explicar o aumento da pressão da artéria pulmonar e da resistência vascular pulmonar. A maioria dos pacientes é assintomática até que desenvolva dispnéia aos esforços, o que geralmente ocorre quando a pressão média na artéria pulmonar ultrapassa o valor de 40 mmHg. A mortalidade é elevada pela associação de doença hepática e hipoxemia progressiva ou falência ventricular direita. Novos estudos são necessários para se estabelecer os benefícios do uso dos vasodilatadores orais, inalatórios ou endovenosos e os resultados do transplante hepático, talvez a única possibilidade terapêutica definitiva.

Hepatopulmonary syndrome: role of nitric oxide and clinical aspects

Hepatopulmonary syndrome is defined by oxygenation impairment due to abnormal intrapulmonary vascular dilatations in patients with liver disease. The implication of enhanced pulmonary production of nitric oxide in the pathogenesis of intrapulmonary vascular dilatations has been demonstrated both in murine models and in human hepatopulmonary syndrome. The diagnosis of hepatopulmonary syndrome in chronic liver disease is of paramount importance, considering the fact that severe hypoxemia related to hepatopulmonary syndrome may occur in patients with well compensated liver disease and that survival is reduced in patients with hepatopulmonary syndrome relative to non hepatopulmonary syndrome patients. Priority for liver transplantation, which is presently the only cure, has been recently increased in patients with advanced hepatopulmonary syndrome.

Pulmonary arteriovenous malformations after cavopulmonary anastomosis

Pulmonary arteriovenous malformations (PAVMs) are a cause of progressive cyanosis after cavopulmonary anastomosis in children with single ventricle physiology who are on the pathway leading to a Fontan procedure. Investigations into possible mechanisms for the etiology of PAVMs are ongoing and suggest that the liver might play a key regulatory role in the development of these lesions.

Improvement of hepatopulmonary syndrome after transjugular intrahepatic portasystemic shunting: case report and review of literature

The hepatopulmonary syndrome has been described in as many as 5-29% of patients with liver disease. Patients with this syndrome may suffer from chronic hypoxemia, and mortality rates of liver patients with this syndrome are as high as 41%. Early diagnosis of such patients is essential. Currently, liver transplantation is the only effective therapy for such patients, and reversal of this syndrome is seen in up to 80% of patients post-transplant. Transjugular intrahepatic portasystemic shunting (TIPS) as a therapeutic maneuver for this syndrome has been described in five patients to date with mixed results. Reduction in portal hypertension with consequent redistribution of blood flow and altered synthesis of vasodilatory chemicals have been postulated to help resolve this disease. In this report, we describe an 11-yr-old female with biliary atresia and hepatopulmonary syndrome. Her disease was complicated with recurrent variceal bleeding. TIPS achieved a therapeutic response of both her bleeding and respiratory complications.

Prevention of gram-negative translocation reduces the severity of hepatopulmonary syndrome

Hepatopulmonary syndrome (HPS) is characterized by intrapulmonary vascular dilatations and an increased alveoloarterial oxygen difference (AaPO(2)). These abnormalities are related to augmented pulmonary nitric oxide (NO) production, dependent primarily on increases in the expression and activity of inducible NO-synthase (iNOS) within pulmonary intravascular macrophages and, to a lesser extent, of endothelial NOS (eNOS). Production of iNOS by pulmonary intravascular macrophages might be related to translocated gut bacteria present in the pulmonary circulation. To test this hypothesis, we determined whether macrophage sequestration, lung iNOS expression and activity, and HPS severity were decreased after norfloxacin was given for 5 weeks to prevent Gram-negative bacterial translocation in rats with common bile duct ligation-induced cirrhosis. Norfloxacin decreased the incidence of Gram-negative translocation from 70 to 0% and the percentage of pulmonary microvessels containing more than 10 macrophages from 52 +/- 7 to 21 +/- 8% (p < 0.01). AaPO(2) and cerebral uptake of intravenous (99m)Tc-labeled albumin macroaggregates (reflecting intrapulmonary vascular dilatations) were intermediate to those of untreated cirrhotic and sham-operated rats. The activity and expression of lung iNOS, but not eNOS, were reduced to normal. Norfloxacin may reduce HPS severity by inhibiting Gram-negative bacterial translocation, thereby decreasing NO production by pulmonary intravascular macrophages. Bacterial translocation may be the key to the pathogenesis of HPS.

Implications of estradiol and progesterone in pulmonary vasodilatation in cirrhotic patients

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

Role of nitric oxide in hepatopulmonary syndrome in cirrhotic rats

The hepatopulmonary syndrome (HPS) is characterized by intrapulmonary vascular dilatations and an increased alveolar-arterial oxygen difference (AaPO(2)). Exhaled nitric oxide (NO) concentrations are elevated, suggesting that pulmonary NO overproduction may be the mechanism underlying HPS. We investigated whether common bile duct ligation in rats results in lung NO overproduction and whether normalization of NO synthesis by a 6-wk course of N(G)-nitro-L-arginine methyl ester (L-NAME) (5 mg x kg(-)(1) x d(-)(1)) prevents HPS. Untreated cirrhotic rats showed increases in AaPO(2) and in cerebral uptake of intravenous (99m)Tc-labeled albumin macroaggregates (indicating intrapulmonary vascular dilatations), with decreases in pulmonary vascular resistance and in pulmonary vasoconstriction induced by angiotensin II and hypoxia. Increases were found in exhaled NO; pulmonary total and calcium-dependent NO synthase (NOS) activities; and pulmonary expression of inducible and, to a lesser extent, endothelial NOS. Accumulation of intravascular macrophages accounted for the inducible NOS expression. L-NAME normalized AaPO(2), brain radioactivity, pulmonary vascular resistance, reactivity to hypoxia and angiotensin II, exhaled NO, and NOS activities. These findings suggest that HPS and the associated reduced response to pulmonary vasoconstrictors seen in untreated cirrhotic rats are related to increased pulmonary NO production dependent primarily on increases in the expression and activities of inducible NOS within pulmonary intravascular macrophages.

Pulmonary hypertension associated with liver cirrhosis: an echocardiographic study

Conflicting results about the prevalence of pulmonary hypertension, ranging from 0.25% to 20%, in liver patients with portal hypertension, have previously been reported. The aim of this study was to evaluate pulmonary arterial pressure in a consecutive series of cirrhotic patients, using a noninvasive method. A complete clinical, laboratory, ultrasonographic, and endoscopic evaluation were performed in 83 consecutive liver patients assessed according to Child's classification and Pugh's score and according to evidence of ultrasonographic and/or endoscopic signs of portal hypertension. A complete echocardiographic evaluation was also performed and pulmonary arterial systolic pressure (PASP) was estimated by measuring tricuspidal regurgitation, using the modified Bernoulli equation. These same evaluations were performed by the same observers in a group of 60 healthy volunteers. The results showed a surprisingly high prevalence (about 20%) of pulmonary hypertension. Patients with more severe liver damage and portal hypertension showed a high prevalence for pulmonary hypertension. A progression in the frequency of portopulmonary hypertension (PPH) was found in Child's classification A to C, and in patients without to patients with evidence of portal hypertension. However, increased PASP was detected in some patients belonging to Child's class A, without evidence of portal hypertension. In conclusion, the echocardiographic examination (a noninvasive technique), appears suitable for detecting pulmonary hypertension in patients with compensated liver cirrhosis, and can elucidate some aspects of the clinical course of the so-called PPH syndrome.

Diseases of the hepatopulmonary axis

Hepatopulmonary syndrome is the most widely recognized of the processes associated with end-stage liver disease. Chronic liver dysfunction is associated with pulmonary manifestations due to alterations in the production or clearance of circulating cytokines and other mediators. Hepatopulmonary syndrome results in hypoxemia due to pulmonary vasodilatation with significant arteriovenous shunting and ventilation-perfusion mismatch. Hepatic hydrothorax may develop in patients with cirrhosis and ascites. Rarely, pulmonary hypertension occurs in the setting of portal hypertension. A second group of disorders may primarily affect the lungs and liver (the hepatopulmonary axis). Among these are the congenital conditions alpha(1)-antitrypsin deficiency and cystic fibrosis. Autoimmune liver disease may be associated with lymphocytic interstitial pneumonitis, fibrosing alveolitis, intrapulmonary granulomas, and bronchiolitis obliterans with organizing pneumonia. Sarcoidosis affects the lung and liver in up to 70% of patients. Medications such as amiodarone can result in a characteristic radiologic appearance of pulmonary and hepatic toxic effects. Knowledge of these associations will assist the radiologist in forming a meaningful differential diagnosis and may influence treatment decisions.

Cardiopulmonary dysfunction in cirrhosis

Cirrhosis is associated with several circulatory abnormalities. These include hyperkinetic systemic and splanchnic circulation, hepatopulmonary syndromes including pulmonary hypertension, and cirrhotic cardiomyopathy. Hepatopulmonary syndrome generally refers to hypoxaemia seen in patients with chronic liver disease and appears to be relatively common, although often subclinical. However, significant pulmonary hypertension occurs in 0.2-0.7% of cirrhotic patients. Nitric oxide and/or other vasodilators appear to be involved in the pathogenesis of hepatopulmonary syndrome through induction of pulmonary capillary dilatation which increases the alveolar-arterial oxygen gradient. Cirrhotic cardiomyopathy refers to abnormal left ventricular function which is manifested under conditions of physiological or pharmacological stress. The emergence of liver transplantation as an effective treatment for end-stage liver disease has led to recognition of previously subclinical cardiomyopathy and congestive heart failure accounts for significant morbidity and mortality after this procedure. Diminished myocardial beta-adrenergic receptor function has been shown to play an important role in the pathogenesis of this condition. The contributions of other factors including nitric oxide, catecholamines and membrane fluidity changes are under investigation. Cirrhotic patients also have an increased incidence of other cardiac abnormalities, such as endocarditis and pericardial effusions.

The hepatopulmonary syndrome

The hepatopulmonary syndrome is a disease entity seen in association with liver failure and other disease entities. It is a devastating consequence of liver failure that results in a significant morbidity for affected patients. Currently, there are no identified medications that ameliorate the symptoms of hypoxemia in this disease state. Recent research, however, has begun to unravel the pathobiology of the vascular dilations that arise in the lungs of patients with liver failure. In this article, a compendium of current knowledge is presented, as well as the contemporary methods for identifying and treating patients.