Analysis of impaired exercise capacity in patients with cirrhosis

Relationship of Nonalcoholic Fatty Liver Disease and Heart Failure With Preserved Ejection Fraction

Although there is an established bidirectional relationship between heart failure with reduced ejection fraction and liver disease, the association between heart failure with preserved ejection fraction (HFpEF) and liver diseases, such as nonalcoholic fatty liver disease (NAFLD), has not been well explored. In this paper, the authors provide an in-depth review of the relationship between HFpEF and NAFLD and propose 3 NAFLD-related HFpEF phenotypes (obstructive HFpEF, metabolic HFpEF, and advanced liver fibrosis HFpEF). The authors also discuss diagnostic challenges related to the concurrent presence of NAFLD and HFpEF and offer several treatment options for NAFLD-related HFpEF phenotypes. The authors propose that NAFLD-related HFpEF should be recognized as a distinct HFpEF phenotype.

Exercise and physical activity in cirrhosis: opportunities or perils

Reduced exercise capacity and impaired physical performance are observed in nearly all patients with liver cirrhosis. Physical activity and exercise are physiological anabolic stimuli that can reverse dysregulated protein homeostasis or proteostasis and potentially increase muscle mass and contractile function in healthy subjects. Cirrhosis is a state of anabolic resistance, and unlike the beneficial responses to exercise reported in physiological states, there are few systematic studies evaluating the response to exercise in cirrhosis. Hyperammonemia is a mediator of the liver-muscle axis with net skeletal muscle ammonia uptake in cirrhosis causing signaling perturbations, mitochondrial dysfunction with decreased ATP content, modifications of contractile proteins, and impaired ribosomal function, all of which contribute to anabolic resistance in cirrhosis and have the potential to impair the beneficial responses to exercise. English language-publications in peer-reviewed journals that specifically evaluated the impact of exercise in cirrhosis were reviewed. Most studies evaluated responses to endurance exercise, and readouts included peak or maximum oxygen utilization, grip strength, and functional capacity. Endurance exercise for up to 12 wk is clinically tolerated in well-compensated cirrhosis. Data on the safety of resistance exercise are conflicting. Nutritional supplements enhance the benefits of exercise in healthy subjects but have not been evaluated in cirrhosis. Whether the beneficial physiological responses with endurance exercise and increase in muscle mass with resistance exercise that occur in healthy subjects also occur in cirrhotics is not known. Specific organ-system responses, changes in body composition, or improved long-term clinical outcomes with exercise in cirrhosis need evaluation.

Transjugular intrahepatic portosystemic shunt (TIPS): current indications and strategies to improve the outcomes

Transjugular intrahepatic portosystemic shunt (TIPS) represents a very effective treatment of complications of portal hypertension. Established indications to TIPS in cirrhotic patients include portal hypertensive bleeding and refractory ascites. Over the years additional indications have been proposed, such as the treatment of vascular disease of the liver, hepatic hydrothorax, hepatorenal syndrome and bleeding from ectopic varices. Indications under evaluation include treatment of portal hypertension prior to major abdominal surgery and treatment of portal vein thrombosis. In spite of these advances, there are still uncertainties regarding the appropriate workup for patients to be scheduled for TIPS. Moreover, prevention and management of post-TIPS complications including hepatic encephalopathy and heart failure are still suboptimal. These issues are particularly relevant considering aging in TIPS candidates in Western countries. Correct selection of patients is mandatory to prevent complications which may eventually frustrate the good hemodynamic results and worsen the patient's quality of life or even life expectancy. The possible role of small diameter TIPS to prevent post-procedural complications is discussed.

Frailty, Sarcopenia, and Malnutrition in Cirrhotic Patients

Sarcopenia, frailty, and malnutrition are prevalent complications in patients with end-stage liver disease (ESLD) and are associated with increased risk of morbidity and mortality. It is valuable to measure nutritional status, sarcopenia, and frailty over time in order to create interventions tailored to individuals with ESLD. Evaluating sarcopenia and frailty in patients with ESLD is challenging. Further work is needed to perfect these assessments so that clinicians can incorporate these assessments into their decision-making and management plans for cirrhotic patients.

Etiology of Liver Disease and Cardiovascular Abnormalities in Patients on a Liver Transplantation Waiting List

BACKGROUND The classical cardiovascular risk factors and changes in the circulatory system secondary to end-stage liver disease (ESLD) are associated with an increased risk of cardiac abnormalities (CAs) in patients waiting for liver transplantation (LTx). The aim of this study was to assess the relationship between the etiology of liver disease and the presence of CAs in patients qualified for LTx. MATERIAL AND METHODS The study enrolled patients qualified to LTx due to ESLD at the Clinical Hospital of the Medical University of Warsaw between 2013 and 2016. Out of 396 patients: 65, 157, 117, and 57 had ESLD due to the alcoholic liver disease (ALD), viral infections (VIR), autoimmune disorders (AUTO), and different etiologies (OTHER), respectively. RESULTS An increased frequency of hypertension and diabetes mellitus were observed in ALD and VIR groups, while for hyperlipidemia, the highest rates were observed in ALD and AUTO groups. Significant differences in CAs rates were observed for resting tachycardia, prolonged QT interval, bradycardia, and left ventricular diastolic dysfunction. After adjustment for age, MELD, and Child-Pugh scores, hyperlipidemia (26% vs. 7-15%, p<0.048) was most frequently observed in the AUTO group, while poor aerobic capacity (49% vs. 21-34%, p<0.009) dominated in the OTHER group. CONCLUSIONS The frequency of hyperlipidemia, and poor aerobic capacity were directly related to the etiology of liver disease, while the remaining associations resulted from effects of age, MELD, and Child-Pugh score.

Cirrhotic cardiomyopathy: the liver affects the heart

Cirrhotic cardiomyopathy historically has been confused as alcoholic cardiomyopathy. The key points for diagnosis of cirrhotic cardiomyopathy have been well explained, however this entity was neglected for a long time. Nowadays the diagnosis of this entity has become important because it is a factor that contributes significantly to morbidity-mortality in cirrhotic patients. Characteristics of cirrhotic cardiomyopathy are a hyperdynamic circulatory state, altered diastolic relaxation, impaired contractility, and electrophysiological abnormalities, particularity QT interval prolongation. The pathogenesis includes impaired function of beta-receptors, altered transmembrane currents and overproduction of cardiodepressant factors, such as nitric oxide, cytokines and endogenous cannabinoids. In addition to physical signs of hyperdynamic state and heart failure under stress conditions, the diagnosis can be done with dosage of serum markers, electrocardiography, echocardiography and magnetic resonance. The treatment is mainly supportive, but orthotopic liver transplantation appears to improve this condition although the prognosis of liver transplantation in patients with cirrhotic cardiomyopathy is uncertain.

Exercise as an intervention for patients with end-stage liver disease: Systematic review

BACKGROUND

Various etiologies of chronic liver disease often result in cirrhosis. Beside obvious liver-related complications, cirrhosis also leads to loss of muscle mass and decreased exercise capacity. In this study, our aim was to conduct a systematic review of literature to investigate the efficacy of exercise interventions in patients with cirrhosis.

METHOD

PubMed was used to perform the literature search. The mesh terms used were the following: (liver (and) cirrhosis (and) exercise or (exercise therapy)). The following terms were excluded: Non-alcoholic fatty liver disease (NAFLD). The search was limited to the English language and human research. The initial search was conducted on December 6, 2016 and re-reviewed May 2017.

RESULTS

Seven studies met selection criteria. Training interventions ranged between 4 and 14 weeks in duration with an exercise frequency of 3 to 5 days per week. Most studies demonstrated an increase in maximal oxygen consumption using gas exchange techniques. Two of 3 studies demonstrated increased distance covered in the 6-minute walk test. One study showed a clinically significant decrease in hepatic venous pressure gradient, while another showed a transient increase only during exercise. There were no adverse effects of the exercise program reported.

CONCLUSIONS

Exercise in selected patients with cirrhosis can have potential benefit in endurance and functional outcome measures without adverse effect from exercise.

Preoperative optimization for major hepatic resection

PURPOSE

Major hepatic resections are performed for primary hepatobiliary malignancies, metastatic disease, and benign lesions. Patients with chronic liver disease, including cirrhosis and steatosis, are at an elevated risk of malnutrition and impaired strength and exercise capacity, deficits which cause increased risk of postoperative complications and mortality. The aims of this report are to discuss the pathophysiology of changes in nutrition, exercise capacity, and muscle strength in patient populations likely to require major hepatectomy, and review recommendations for preoperative evaluation and optimization.

METHODS

Nutritional and functional impairment in preoperative hepatectomy patients, especially those with underlying liver disease, have a complex and multifactorial physiologic basis that is not completely understood.

RESULTS

Recognition of malnutrition and compromised strength and exercise tolerance preoperatively can be difficult, but is critical in providing the opportunity to intervene prior to major hepatic resection and potentially improve postoperative outcomes. There is promising data on a variety of nutritional strategies to ensure adequate intake of calories, proteins, vitamins, and minerals in patients with cirrhosis and reduce liver size and degree of fatty infiltration in patients with hepatic steatosis. Emerging evidence supports structured exercise programs to improve exercise tolerance and counteract muscle wasting.

CONCLUSIONS

The importance of nutrition and functional status in patients indicated for major liver resection is apparent, and emerging evidence supports structured preoperative preparation programs involving nutritional intervention and exercise training. Further research is needed in this field to develop optimal protocols to evaluate and treat this heterogeneous cohort of patients.

ALTERAÇÕES DO SISTEMA CARDIOPULMONAR DE PACIENTES CIRRÓTICOS

RESUMO Introdução: A cirrose gera alterações nas trocas gasosas e a desnutrição proteico-calórica em pacientes hepatopatas. Objetivo: Avaliar e comparar as variáveis cardiopulmonares, a força do aperto de mão (FAM) e a composição corporal entre pacientes cirróticos pelo vírus da hepatite C e indivíduos saudáveis, e correlacionar o consumo máximo de oxigênio (VO2MAX) com a FAM. Métodos: Esta pesquisa caracteriza-se como estudo de caso-controle composto por 36 participantes (18 pacientes cirróticos com HCV e 18 indivíduos hígidos) de ambos os sexos, maiores de 18 anos. A força de preensão palmar foi mensurada por dinamometria com dinamômetro mecânico de empunhadura com alça ajustável. As variáveis ventilatórias foram avaliadas por ergoespirometria com teste de carga progressiva em cicloergômetro. A composição corporal foi mensurada por um técnico em cineantropometria nível II. Foram utilizados os testes t independente e Mann-Whitney para comparação entre os grupos e a correlação de Spearman para associação entre as variáveis. Resultados: Foram encontradas diferenças no consumo máximo de oxigênio 16,20 (11,60-18,55), mediana e intervalo interquartil x 19,90 (16,27-26,85), ventilação 45,40 (36,45-54,20) x 63,40 (50,40-78,00), produção de dióxido de carbono 785,88 (655,81-963,14) x 988,04 (826,93-1546,21), frequência cardíaca máxima (127,66 ± 23,26 média e ± DP) x (146,29 ± 23,31), primeiro limiar ventilatório (10,700 ± 3,19) x (14,912 ± 4,45) e segundo limiar ventilatório (14,16 ± 4,48) x (18,25 ± 5,54) entre cirróticos e controles, respectivamente. Encontramos correlação positiva moderada entre o consumo máximo de oxigênio e a força do aperto de mão (r = 0,474, p = 0,047). Conclusão: Existem alterações nas variáveis cardiopulmonares e há associação entre o VO2MAX e a FAM em pacientes cirróticos pelo vírus da hepatite C.

N-Terminal pro-B-Type Natriuretic Peptide Levels are Linked with Modified Child-Pugh Classification in Patients with Nonalcoholic Cirrhosis [NT-ProBNP and Liver Cirrhosis]

Excess N-terminal pro-brain natriuretic peptide secretion has been linked to cirrhosis in previously studies. The relationship of plasma N-terminal pro-brain natriuretic peptide levels and cardiac dysfunction determined by echocardiography were investigated in patients with nonalcoholic cirrhosis and a control group of chronic hepatitis. This study was designed as a cross-sectional study. Thirty-two men and thirty-three women who gave informed consent who were followed-up for chronic liver failure were enrolled. All patients gave clinical history, physical examination was carried out and information about ongoing medication has been obtained. Serum N-terminal pro-brain natriuretic peptide level was measured in all patients. The same cardiologist determined ejection fraction, end-diastolic left ventricular diameter, interventricular septum, and posterior wall on transthoracic echocardiography. Patients with extensive liver disease according to Child-Pugh classification from A to C had increasing N-terminal pro-brain natriuretic peptide levels in association (P < .001). According to the Child-Pugh classification there were no significant difference between groups for echocardiographic measurements (P > .05). N-terminal pro-brain natriuretic peptide may be an important marker for cardiac dysfunction in patients with chronic liver failure in accordance with Child-Pugh stage.

Functional Capacity, Respiratory Muscle Strength, and Oxygen Consumption Predict Mortality in Patients with Cirrhosis

Introduction. Liver diseases influence musculoskeletal functions and may negatively affect the exercise capacity of patients with cirrhosis. Aim. To test the relationship between the six-minute walk test (6MWT), maximal inspiratory pressure (MIP), and exercise capacity (VO2peak) measures and the survival rate of patients with cirrhosis. Methods. This prospective cohort study consisted of 86 patients diagnosed with cirrhosis with the following aetiology: hepatitis C virus (HCV), hepatitis B virus (HBV), and/or alcoholic cirrhosis (AC). All patients were followed up for three years and submitted to the 6MWT, pressure measurements with a compound gauge, and an exercise test (VO2peak). Results. The survival analysis showed that the individuals who covered a distance shorter than 410 m during the 6MWT had a survival rate of 55% compared with a rate of 97% for the individuals who walked more than 410 m (p = 0.0001). Individuals with MIPs below -70 cmH2O had a survival rate of 62% compared with a rate of 93% for those with MIPs above -70 cmH2O (p = 0.0001). The patients with values below 17 mL/kg had a survival rate of 55% compared with a rate of 94% for those with values above 17 mL/kg (p = 0.0001). Conclusion. The 6MWT distance, MIP, and oxygen consumption are predictors of mortality in patients with cirrhosis.

Preoperative cardiovascular investigations in liver transplant candidate: An update

Cardiovascular complications are a major cause of morbidity and mortality in patients with end-stage liver disease (ESLD) undergoing liver transplantation. Identifying candidates at the highest risk of postoperative cardiovascular complications is the cornerstone for optimizing the outcome. Ischaemic heart disease contributes to major portion of cardiovascular complications and therefore warrants evaluation in the preoperative period. Patients of ESLD usually demonstrate increased cardiac output, compromised ventricular response to stress, low systemic vascular resistance and occasionally bradycardia. Despite various recommendations for preoperative evaluation of cardiovascular disease in liver transplant candidates, a considerable controversy on screening methodology persists. This review critically focuses on the rapidly expanding body of evidence for diagnosis and risk stratification of cardiovascular disorder in liver transplant candidates.

Cardiac imaging in patients with chronic liver disease

Cirrhotic cardiomyopathy (CCM) is characterized by an impaired contractile response to stress, diastolic dysfunction and the presence of electrophysiological abnormalities, and it may be diagnosed at rest in some patients or demasked by physiological or pharmacological stress. CCM seems to be involved in the development of hepatic nephropathy and is associated with an impaired survival. In the field of cardiac imaging, CCM is not yet a well-characterized entity, hence various modalities of cardiac imaging have been applied. Stress testing with either physiologically or pharmacologically induced circulatory stress has been used to assess systolic dysfunction. Whereas echocardiography with tissue Doppler is by far the most preferred method to detect diastolic dysfunction with measurement of E/A- and E/E'-ratio. In addition, echocardiography may also possess the potential to evaluate systolic dysfunction at rest by application of new myocardial strain techniques. Experience with other modalities such as cardiac magnetic resonance imaging and cardiac computed tomography is limited. Future studies exploring these imaging modalities are necessary to characterize and monitor the cardiac changes in cirrhotic patients.

The influence that hepatic cirrhosis provides in exercise capacity and muscle strength: a review

AbstractIntroduction Hepatic cirrhosis leads to a series of physiological changes, among which stand out cardiorespiratory and muscle impairments. These changes determine a negative impact on quality of life and may cause physical inactivity.Objective The objective of this study was to review, in the most current scientific literature, the influence that hepatic cirrhosis provides in exercise capacity and muscle strength, and the effect of exercise when applied to this situation.Materials and methods For this review, research on original studies was carried out on Medical Literature Analysis and Retrieval System Online (assessed by PubMed), Scopus and Web of Science between the years 1990 to 2015. In order to be included, studies had to meet the following criteria: a) be from original articles; b) evaluate exercise capacity or muscle strength; and c) provide relevant results.Results and Discussion : The majority of studies concluded that the exercise capacity and muscle strength are decreased in individuals with cirrhosis when compared to control subjects.Final considerations Hepatic cirrhosis has negative effect on cardiorespiratory and neuromuscular capacity during physical exercise in individuals with liver disease.

Impaired functional capacity in potential liver transplant candidates predicts short-term mortality before transplantation

Liver transplantation (LT) is a lifesaving treatment. Because of the shortage of donor organs, some patients will not survive long enough to receive a transplant. The identification of LT candidates at increased risk of short-term mortality without transplantation may affect listing decisions. Functional capacity, determined with cardiopulmonary exercise testing (CPET), is a measure of cardiorespiratory reserve and predicts perioperative outcomes. This study examined the association between functional capacity and short-term survival before LT and the potential for CPET to predict 90-day mortality without transplantation. A total of 176 patients who were assessed for nonacute LT underwent CPET. Ninety days after the assessment, 10 of the 164 patients who had not undergone transplantation were deceased (mortality rate = 6.1%). According to a comparison of survivors and nonsurvivors, the Model for End-Stage Liver Disease score, UK Model for End-Stage Liver Disease (UKELD) score, age, anaerobic threshold, and peak oxygen uptake (VO(2)) were significant univariate predictors of 90-day mortality without transplantation, but only the UKELD score and peak VO(2) retained significance in a multivariate analysis. The mean peak VO(2) was significantly lower for nonsurvivors versus survivors (15.2 ± 3.3 versus 21.2 ± 5.3 mL/minute/kg, P < 0.001). According to a receiver operating characteristic (ROC) curve analysis, peak VO(2) performed well as a diagnostic test (area under the ROC curve = 0.84, 95% confidence interval = 0.76-0.92, sensitivity = 0.90, specificity = 0.74, P < 0.001). The optimal cutoff value for predicting mortality was ≤17.6 mL/minute/kg. The positive predictive value of a peak VO(2)  ≤ 17.6 mL/minute/kg for 90-day mortality was greatest for patients with high UKELD scores: 38% of the patients with a UKELD score ≥ 57 and a peak VO(2)  ≤ 17.6 mL/minute/kg died, whereas only 6% of the patients with a UKELD score ≥ 57 and a peak VO(2)  > 17.6 mL/minute/kg died (P = 0.03). In conclusion, patients assessed for LT with an impaired functional capacity have poorer short-term survival; this is particularly true for individuals with worse liver disease severity.

Aerobic capacity during cardiopulmonary exercise testing and survival with and without liver transplantation for patients with chronic liver disease

Chronic liver disease (CLD) is associated with muscle wasting, reduced exercise tolerance and aerobic capacity (AC). Measures of AC determined with cardiopulmonary exercise testing (CPET) may predict survival after liver transplantation (LT), but the relationship with nontransplant outcomes is uncertain. In patients assessed for LT, we examined the relationship of CPET AC parameters with the severity of liver disease, nutritional state, and survival with and without LT. Patients assessed for elective first LT who underwent CPET and an anthropometric assessment at a single center were studied. CPET-derived measures of AC that were evaluated included the peak oxygen consumption (VO2 peak) and the anaerobic threshold (AT). Three hundred ninety-nine patients underwent CPET, and 223 underwent LT; 45% of the patients had a VO2 peak < 50% of the predicted value, and 31% had an AT < 9 mL/kg/minute. The VO2 peak and AT values correlated with the Model for End-Stage Liver Disease score, but they more closely correlated with serum sodium and albumin levels. The handgrip strength correlated strongly with the VO2 peak. Patients with impaired AC had prolonged hospitalization after LT, and nonsurvivors had lower AT values than survivors 1 year after transplantation (P < 0.05); this was significant in a multivariate analysis. One hundred seventy-six patients did not undergo LT; the 1-year mortality rate was 34.6%. The AT (P < 0.05) and VO2 peak values (P < 0.001) were lower for nonsurvivors. In a multivariate analysis, AT was independently associated with nonsurvival. In conclusion, AC was markedly impaired in many patients with CLD. In patients who did not undergo transplantation, impaired AT was predictive of mortality, and in patients undergoing LT, it was related to postoperative hospitalization and survival. AC should be evaluated as a modifiable factor for improving patient survival whether or not LT is anticipated.

Exercise limitation following transplantation

Organ transplantation is one of the medical miracles or the 20th century. It has the capacity to substantially improve exercise performance and quality of life in patients who are severely limited with chronic organ failure. We focus on the most commonly performed solid-organ transplants and describe peak exercise performance following recovery from transplantation. Across all of the common transplants, evaluated significant reduction in VO2peak is seen (typically renal and liver 65%-80% with heart and/or lung 50%-60% of predicted). Those with the lowest VO2peak pretransplant have the lowest VO2peak posttransplant. Overall very few patients have a VO2peak in the normal range. Investigation of the cause of the reduction of VO2peak has identified many factors pre- and posttransplant that may contribute. These include organ-specific factors in the otherwise well-functioning allograft (e.g., chronotropic incompetence in heart transplantation) as well as allograft dysfunction itself (e.g., chronic lung allograft dysfunction). However, looking across all transplants, a pattern emerges. A low muscle mass with qualitative change in large exercising skeletal muscle groups is seen pretransplant. Many factor posttransplant aggravate these changes or prevent them recovering, especially calcineurin antagonist drugs which are key immunosuppressing agents. This results in the reduction of VO2peak despite restoration of near normal function of the initially failing organ system. As such organ transplantation has provided an experiment of nature that has focused our attention on an important confounder of chronic organ failure-skeletal muscle dysfunction.

Response to exercise in patients with liver cirrhosis: implications for liver transplantation

End-stage liver cirrhosis is a systemic disease carrying a short-term desperate prognosis without liver transplantation. Given the discrepancy between the growing number of candidates and the limited available liver grafts, the pre-transplantation screening process has become a challenging task. Cardiopulmonary exercise testing, by measuring maximal oxygen consumption at peak exercise, provides a global integrative approach of the health status of an individual. In the setting of liver cirrhosis, decreased oxygen consumption at peak exercise may result from a combination of multiple extra-hepatic complications, including deconditioning, malnutrition-associated muscle weakness, anaemia, cirrhotic cardiomyopathy, and hepato-pulmonary syndrome for instance. In addition, oxygen consumption at peak exercise not only correlated with the severity of the liver disease, but it is also independently associated with survival following liver transplantation. The present article aims to review the numerous determinants of impaired aerobic capacity in patients with severe liver disease, and to discuss how useful is cardiopulmonary exercise testing as a critical tool in the pre-transplantation assessment of these patients.

LEFT ventricular function assessed by echocardiography in cirrhosis: relationship to systemic hemodynamics and renal dysfunction

BACKGROUND & AIMS

The current study aimed at assessing the potential role of cardiac abnormalities in the pathogenesis of circulatory and renal dysfunction in cirrhosis.

METHODS

One hundred and fifty-two patients (34 without ascites, 95 with ascites without renal failure and 21 with hepatorenal syndrome) were evaluated using Doppler echocardiography. In 102 patients, diastolic function was assessed by measuring parameters related to ventricular filling velocity, mitral annulus velocity and left atrial dimensions. Cardiopulmonary pressures were also measured by cardiac catheterization in 54 patients. In 50 additional patients, left ventricular myocardial strain was performed to estimate myocardial contractility and systolic function.

RESULTS

Grade 1 and 2 diastolic dysfunction was present in 41% and 16% of the patients, respectively. There was no patient with severe grade 3 diastolic dysfunction. Grade 2 diastolic dysfunction was associated with higher cardiopulmonary pressures but values were within the normal limits in all cases. Diastolic dysfunction directly correlated with liver failure but not with the degree of impairment in circulatory and renal function. The proportion of patients without or with grade 1 or 2 diastolic dysfunction was similar in patients with compensated cirrhosis, with ascites without renal failure or with hepatorenal syndrome despite marked differences in the degree of circulatory dysfunction, as indicated by plasma renin activity and noradrenaline concentration. The heart rate and systolic function were normal in all cases. There were no differences between patients without ascites, with ascites without renal failure or with HRS, despite marked differences in the activity of the renin-angiotensin system and sympathetic nervous system. These features indicate an impaired response of cardiac chronotropic and inotropic function to changes in systemic hemodynamics.

CONCLUSIONS

These data indicates that: (1) diastolic dysfunction is frequent in cirrhosis but in most cases it is of mild degree and does not increase the cardiopulmonary pressure to abnormal levels. This feature, which may be due to the central hypovolemia of cirrhosis, probably accounts for the lack of symptoms associated with this condition. (2) Diastolic dysfunction in cirrhosis is unrelated to circulatory dysfunction, ascites and HRS. (3) In cirrhosis, there is a lack of response of the left ventricular systolic and chronotropic function to peripheral arterial vasodilation and activation of the sympathetic nervous system and this feature is an important contributory factor to the progression of circulatory dysfunction and the pathogenesis of ascites and HRS.

Exercise capacity and muscle strength in patients with cirrhosis

Exercise capacity and muscle strength are predictors of outcome in a number of clinical populations. Advanced liver disease is a catabolic state, and patients often have muscle wasting. However, the relationships between exercise capacity, strength, and outcomes for patients undergoing liver transplantation are poorly understood. Thirteen studies have examined the association between these parameters in patients with cirrhosis, and they have found a significant reduction in the exercise capacity and muscle strength of patients with cirrhosis versus healthy controls. These impairments appear to be independent of the etiology of cirrhosis, but the data are equivocal with respect to their association with disease severity. Two studies reported a significant and independent association between pretransplant exercise capacity and posttransplant survival. Another 2 studies found that exercise training was well tolerated in patients with cirrhosis and resulted in improvements in exercise capacity (both studies) and muscle mass (1 study). These data are provocative and suggest that measuring and improving the exercise capacity and muscle strength of patients with cirrhosis who are awaiting liver transplantation could potentially improve outcomes.

Capacidade funcional e força muscular respiratória de candidatos ao transplante hepático

INTRODUÇÃO: A doença hepática crônica resulta em grande impacto funcional, causando perda de massa e função muscular com consequente redução da capacidade funcional. OBJETIVO: Avaliar e comparar a força muscular respiratória e a capacidade funcional dos candidatos ao transplante hepático que possuem classe B ou C segundo o Child-Pugh Score e correlacionar estas variáveis dentro de cada grupo. MÉTODOS: Estudo transversal, com amostra de conveniência composta por 35 pacientes, divididos em dois grupos a partir da pontuação obtida no Child-Pugh Score, sendo B (19 pacientes) e C (16 pacientes). Todos os indivíduos foram avaliados em um único momento, sendo mensuradas as pressões inspiratória máxima (PImáx) e expiratória máxima (PEmáx) e a distância percorrida no teste de caminhada de seis minutos (TC6M). RESULTADOS: Os indivíduos classificados com Child-Pugh Score B apresentaram maiores valores na PImáx (-86,05 ± 23,89 vs. -57,94 ± 14,14), p = 0,001, na PEmáx (84,16 ± 28,26 vs. 72,00 ± 16,94), p = 0,142, e na distância percorrida no TC6M (473,63 ± 55,276 vs. 376,13 ± 39,00), p = 0,001. Encontramos, ainda, correlação positiva entre os valores da PImáx e a distância percorrida no TC6M dentro grupo Child-Pugh Score B, r = 0,64 e p = 0,003. CONCLUSÃO: O progresso da doença hepática contribui para o surgimento de diversas complicações que, em conjunto, parecem contribuir para a redução da capacidade funcional dos indivíduos. Em nosso trabalho, isso ficou evidenciado pelo pior desempenho do grupo Child-Pugh Score C. Isto pode sugerir que a espera para o transplante hepático (TxH) pode agravar a capacidade funcional e a força muscular respiratória desses indivíduos.

Cardiac structural and functional alterations in infants and children with biliary atresia, listed for liver transplantation

BACKGROUND & AIMS

Cirrhotic liver diseases are associated with abnormalities in cardiac geometry and function in adults (cirrhotic cardiomyopathy) but rarely explored in cirrhotic infants or children. We proposed that features of cirrhotic cardiomyopathy are present in infants with cirrhosis due to biliary atresia (BA) as early as the time of evaluation for liver transplant and will correlate with mortality and postoperative morbidity.

METHODS

Two-dimensional echocardiography (2DE) of infants with BA (n=40; median age, 8 months), listed for transplantation at the Texas Children's Hospital from 2004 to 2010, were reviewed and compared with age- and sex-matched infants without cardiac or liver disease (controls). Length of stay and correlation with 2DE results were assessed.

RESULTS

Compared with controls, children with BA had significant increases in multiple 2DE parameters, notably left ventricle wall thickness (23% increase), left ventricular (LV) mass indexed to body surface area (51% increase), and LV shortening fraction (8% increase). Overall, features of cirrhotic cardiomyopathy were observed in most infants (29/40; 72%); 17 had hyperdynamic contractility, and 24 had altered LV geometry. After liver transplantation (33), infants with abnormal 2DE results had longer stays in the intensive care unit (median, 6 vs 4 days) and the hospital (21 vs 11 days) compared with infants who had normal 2DE reports. On univariate analysis, the length of hospital stay correlated with LV mass index.

CONCLUSIONS

Cardiomyopathy is a prevalent condition in infants with end-stage cirrhotic liver disease due to BA (>70%). This underrecognized condition likely contributes to the prolongation of posttransplant hospitalization.

Cardiopulmonary response to exercise in patients with liver cirrhosis and impaired pulmonary gas exchange

Maximal exercise capacity and pulmonary gas exchange are both commonly impaired in liver cirrhosis. Apart from rare cases of hepatopulmonary syndrome, it is still unknown whether these moderate pulmonary gas exchange abnormalities can alter aerobic capacity of cirrhotic patients. Resting pulmonary function tests and symptom-limited cardiopulmonary exercise testing were prospectively investigated in 30 patients with liver cirrhosis exhibiting a widened alveolar-arterial oxygen gradient (P(A-a)O(2) > 30 mm Hg at peak exercise) without pulmonary vascular dilatations at contrast-enhanced echocardiography. Data were compared with those of 30 normoxemic cirrhotic controls (matched for age, gender, body mass index, etiology and severity of liver disease, smoking habits, hemoglobin level, and beta-blocker therapy). Resting cardiopulmonary parameters were within normal range in both groups except carbon monoxide lung transfer (TLCO, 60.4 ± 2.9 vs 74.3 ± 2.8% in controls, p = 0.0004) and P(A-a)O(2) (28.8 ± 2 vs 15.3 ± 2 mm Hg in controls, p < 0.0001). Cirrhotics with impaired gas exchange during exercise exhibited a significant reduction in maximal oxygen uptake (VO(2)max, 1.18 ± 0.07 (53% predicted) vs 1.41 ± 0.07 L/min (62% predicted), p = 0.004), a higher ventilation level at ventilatory threshold (V(E)/VO(2), 39.2 ± 1.5 vs 35.3 ± 1.5, p = 0.01) without ventilatory limitation, and a greater dead space to tidal volume ratio (V(D)/V(T)max, 0.32 ± 0.01 vs 0.25 ± 0.01, p = 0.01). VO(2)max correlates negatively with V(D)/V(T)max (r(2) = 0.36; p < 0.0001). There were no differences in cardiac or metabolic response to exercise between groups. Taken together these findings suggest that clinically undetectable pulmonary vascular disorders can slightly contribute to further reduce exercise capacity of cirrhotic patients.

The heart in liver transplantation

The heart and liver are organs that are closely related in both health and disease. Patients who undergo liver transplantation may suffer from heart disease that is: (a) related to the original cause of the liver disease such as hemochromatosis, (b) related to the liver disease itself, or (c) related to other associated conditions. Furthermore, liver transplantation is one of the most cardiovascular stressful events that a patient with cirrhosis may undergo. After liver transplantation, the progression of pre-existing or the development of new-onset cardiac disease may occur. This article reviews the relationship between the heart and liver transplantation in the pre-transplant, intra-operative, and post-transplant periods.

Cirrhotic cardiomyopathy

Increased cardiac output was first described in patients with cirrhosis more than fifty years ago. Later, various observations have indicated the presence of a latent cardiac dysfunction, which includes a combination of reduced cardiac contractility with systolic and diastolic dysfunction and electrophysiological abnormalities. This syndrome is termed cirrhotic cardiomyopathy. Results of experimental studies indicate the involvement of several mechanisms in the pathophysiology, such as reduced beta-adrenergic receptor signal transduction, altered transmembrane currents and electromechanical coupling, nitric oxide overproduction, and cannabinoid receptor activation. Systolic incompetence in patients can be revealed by pharmacological or physical strain and during stressful procedures, such as transjugular intrahepatic portosystemic shunt insertion and liver transplantation. Systolic dysfunction has recently been implicated in development of renal failure in advanced disease. Diastolic dysfunction reflects delayed left ventricular filling and is partly attributed to ventricular hypertrophy, subendocardial oedema, and altered collagen structure. The QT interval is prolonged in about half of the cirrhotic patients and it may be normalised by beta-blockers. No specific therapy for cirrhotic cardiomyopathy can be recommended, but treatment should be supportive and directed against the cardiac dysfunction. Future research should better describe the prevalence, impact on morbidity and survival, and look for potential treatments.

Hypertrophic cardiomyopathy and dysregulation of cardiac energetics in a mouse model of biliary fibrosis

Cardiac dysfunction is a major cause of morbidity and mortality in patients with end-stage liver disease; yet the mechanisms remain largely unknown. We hypothesized that the complex interrelated impairments in cardiac structure and function secondary to progression of liver diseases involve alterations in signaling pathways engaged in cardiac energy metabolism and hypertrophy, augmented by direct effects of high circulating levels of bile acids. Biliary fibrosis was induced in male C57BL/6J mice by feeding a 0.1% 3,5-diethoxycarbonyl-1,4-dihydroxychollidine (DDC) supplemented diet. After 3 weeks, mice underwent live imaging (dual energy x-ray absorptiometry [DEXA] scanning, two-dimensional echocardiography [2DE], electrocardiography, cardiac magnetic resonance imaging), exercise treadmill testing, and histological and biochemical analyses of livers and hearts. Compared with chow-fed mice, DDC-fed mice fatigued earlier on the treadmill, with reduced VO(2). Marked changes were identified electrophysiologically (bradycardia and prolonged QT interval) and functionally (hyperdynamic left ventricular [LV] contractility along with increased LV thickness). Hearts of DDC-fed mice showed hypertrophic signaling (activation of v-akt murine thymoma viral oncogene/protein kinase B [AKT], inhibition of glycogen synthase kinase-3beta [GSK3beta], a 20-fold up-regulation of beta myosin heavy chain RNA and elevated G(s)alpha/G(i)alpha ratio. Genes regulating cardiac fatty acid oxidation pathways were suppressed, along with a threefold increase in myocardial glycogen content. Treatment of mouse cardiomyocytes (which express the membrane bile acid receptor TGR5) with potent natural TGR5 agonists, taurochenodeoxycholic acid and lithocholic acid, activated AKT and inhibited GSK3beta, similar to the changes seen in DDC-fed mouse hearts. This provides support for a novel mechanism whereby circulating natural bile acids can induce signaling pathways in heart associated with hypertrophy.

CONCLUSION

Three weeks of DDC feeding-induced biliary fibrosis leads to multiple functional, metabolic, electrophysiological, and hypertrophic adaptations in the mouse heart, recapitulating some of the features of human cirrhotic cardiomyopathy.

The heart and the liver

Cardiac failure affects the liver and liver dysfunction affects the heart. Chronic and acute heart failure can lead to cardiac cirrhosis and cardiogenic ischemic hepatitis. These conditions may impair liver function and treatment should be directed towards the primary heart disease and seek to secure perfusion of vital organs. In patients with advanced cirrhosis, physical and/or pharmacological stress may reveal a reduced cardiac performance with systolic and diastolic dysfunction and electrophysical abnormalities, termed cirrhotic cardiomyopathy. Pathophysiological mechanisms include reduced beta-adrenergic receptor signal transduction and defective cardiac electromechanical coupling. However, the QT interval is prolonged in approximately half of patients with cirrhosis and it may be improved by beta-blockers. No specific therapy can be recommended but it should be supportive and directed against the heart failure. Transjugular intrahepatic portosystemic shunt insertion and liver transplantation affect cardiac function in portal hypertensive patients and cause stress to the cirrhotic heart, with a risk of perioperative heart failure. The risk and prevalence of coronary artery disease are increasing in cirrhotic patients and since perioperative mortality is high, careful evaluation of such patients with dobutamine stress echocardiography, coronary angiography and myocardial perfusion imaging is required prior to liver transplantation. Future research should focus on beneficial effects of treatment on cardiac function and mortality.

Impact of impaired aerobic capacity on liver transplant candidates

BACKGROUND

Oxygen consumption at peak exercise (peak VO2) is the most accurate index of aerobic capacity (AC), which reflects the physical condition of an individual and is currently considered the gold standard for cardiorespiratory fitness. Evaluation of peak VO2 to identify high-risk candidates for liver transplantation (LT) may represent an interesting approach. The aims of this study were (a) to describe AC and identify factors independently associated with peak VO2; (b) to analyze the prognostic value of peak VO2 in patients referred for preliminary evaluation of LT; and (c) to provide preliminary data on the influence of peak VO2 on length of hospitalization and the need for oxygen support after LT.

RESULTS

Peak VO2 was determined in patients referred for preliminary evaluation for LT. One hundred thirty-five candidates were included. More than half had severe alterations in peak VO2. Age, gender, model-for-end-stage liver disease (MELD) score, tobacco use, and hemoglobin were independently associated with peak VO2. Candidates with severe alterations in peak VO2 had a lower 1-year survival than others. Model-for-end-stage liver disease score and peak VO2 were independently associated with survival. In patients with a MELD above 17, those with severe alterations of peak VO2 AC had lower 1-year survival than the others. Among patients who underwent LT, those with severe impairment of peak VO2 showed a trend toward a higher mean length of hospitalization after LT and had significantly longer need for oxygen support.

CONCLUSIONS

Peak VO2 is severely impaired in candidates for LT and affects survival and post-LT course. Perioperative respiratory rehabilitation programs validated in lung and heart transplantation must be tested.

Role of exhaled breath biomarkers in environmental health science

As a discipline of public health, environmental health science is the study of the linkage from environmental pollution sources to eventual adverse health outcome. This progression may be divided into two components, (1) "exposure assessment," which deals with the source terms, environmental transport, human exposure routes, and internal dose, and (2) "health effects," which deals with metabolism, cell damage, DNA changes, pathology, and onset of disease. The primary goal of understanding the linkage from source to health outcome is to provide the most effective and efficient environmental intervention methods to reduce health risk to the population. Biomarker measurements address an individual response to a common external environmental stressor. Biomarkers are substances within an individual and are subdivided into chemical markers, exogenous metabolites, endogenous response chemicals, and complex adducts (e.g., proteins, DNA). Standard biomarker measurements are performed in blood, urine, or other biological media such as adipose tissue and lavage fluid. In general, sample collection is invasive, requires medical personnel and a controlled environment, and generates infectious waste. Exploiting exhaled breath as an alternative or supplement to established biomarker measurements is attractive primarily because it allows a simpler collection procedure in the field for numerous individuals. Furthermore, because breath is a gas-phase matrix, volatile biomarkers become more readily accessible to analysis. This article describes successful environmental health applications of exhaled breath and proposes future research directions from the perspective of U.S. Environmental Protection Agency (EPA) human exposure research.

N-terminal pro B-type natriuretic peptide and the evaluation of cardiac dysfunction and severity of disease in cirrhotic patients

PURPOSE

Cardiac dysfunction and hyperdynamic systemic circulation may be present in patients with cirrhosis. The purpose of this study was to identify relations between plasma levels of N-terminal-proBNP (NT-proBNP), reflecting early ventricular dysfunction, and the severity of liver disease and cardiac dysfunction in cirrhotic patients.

MATERIALS AND METHODS

Sixty-three cirrhotic patients and 15 controls (group 1) were enrolled in this study. Plasma levels of NT-proBNP were determined in echocardiographically examined patients, which were allocated to 1 of 3 groups according to Child-Pugh classification or into 2 groups, i.e., a compensated group without ascites (group 2) and decompensated group with ascites (group 3).

RESULTS

Plasma NT-proBNP levels were significantly higher in cirrhotic patients (groups 2 and 3) than in age-matched controls (155.9 and 198.3 vs. 40.3 pg/mL, respectively, p < 0.05). NT-proBNP levels were significantly increased in Child class C patients than in classes B and A (250.0 vs. 168.6 and 119.6 pg/mL, respectively, p < 0.05). Left atrial dimension, wall thickness of left ventricle, and EF or E/E' were significantly increased, and EDT was prolonged in cirrhotic patients than in controls. Increased LVMI and decreased E/A ratio were noted in the group of patients with ascites as compared with the other groups.

CONCLUSION

Plasma NT-proBNP levels were high in cirrhotic patients and are likely to be related to the severity of disease. Advanced cirrhosis is associated with advanced cardiac dysfunction, and NT-proBNP levels has predictive value for concomitant cardiac dysfunction and cirrhosis progression.

Cardiac evaluation of liver transplant candidates

Physicians previously thought that heart disease was rare in patients with end stage liver disease. However, recent evidence shows that the prevalence of ischemic heart disease and cardiomyopathy is increased in transplant candidates compared to most other surgical candidates. Investigators estimate that up to 26% of all liver transplant candidates have at least one critical coronary artery stenosis and that at least half of these patients will die perioperatively of cardiac complications. Cardiomyopathy also occurs in greater frequency. While all patients with advanced cardiac disease have defects in cardiac performance, a larger than expected number of patients have classical findings of dilated, restrictive and hypertrophic cardiomyopathy. This may explain why up to 56% of patients suffer from hypoxemia due to pulmonary edema following transplant surgery. There is considerable controversy on how to screen transplant candidates for the presence of heart disease. Questions focus upon, which patients should be screened and what tests should be used. This review examines screening strategies for transplant candidates and details the prognostic value of common tests used to identify ischemic heart disease. We also review the physiological consequences of cardiomyopathy in transplant candidates and explore the specific syndrome of “cirrhotic cardiomyopathy”.

Exercise performance and ventilatory efficiency in patients with mild and moderate liver cirrhosis

1. The impact of ventilatory efficiency on reduced exercise capacity and recovery oxygen kinetics has not been addressed in cirrhotic patients. The aim of the present study was to investigate exercise performance and ventilatory efficiency in patients with mild and moderate liver cirrhosis (LC). 2. Nineteen male non-hypoxic patients with LC (age 51.3 +/- 9.1 years; body mass index (BMI) 25.6 +/- 3.6 kg/m(2)) classified by the Child-Pugh score as class A (n = 7) and class B (n = 12) and 19 age- and BMI-matched controls participated in the study. Subjects undertook maximal incremental exercise testing on a treadmill using the Bruce protocol. 3. Patients with LC showed a reduced diffusion capacity (D(L,CO)%) compared with controls (74.6 +/- 15.2 vs 95.6 +/- 12.9%, respectively; P < 0.001), but a comparable volume standardized diffusion coefficient (1.33 +/- 0.22 vs 1.45 +/- 0.18 mmol/min per kPa per L, respectively; P = 0.74). Patients with LC had a significantly lower exercise capacity compared with controls (VO(2 max) 23.8 +/- 3.8 vs 30.6 +/- 4.4 mL/min per kg, respectively; P < 0.001). Recovery oxygen kinetics were also impaired in LC patients compared with controls (104.6 +/- 19.3 vs 84.4 +/- 22.7 s, respectively; P = 0.012). The chronotropic index was significantly lower in the LC group compared with controls (0.67 +/- 0.19 vs 0.82 +/- 0.17, respectively; P = 0.030) and LC patients showed higher ventilatory equivalents (30.4 +/- 3.8 vs 26.3 +/- 2.3, respectively; P < 0.001) and lower oxygen uptake efficiency slope values (2187 +/- 445 vs 2745 +/- 473 mL/min per log(10)L, respectively; P < 0.001) compared with controls, which is indicative of decreased ventilatory efficiency. Patients with LC also had a higher standardized maximal exercise perception score (SMEPS) compared with controls (0.62 +/- 0.18 vs 0.46 +/- 0.15, respectively; P = 0.011). Moderate negative correlations were found between Child-Pugh score and VO(2 max)% (r = -0.496; P = 0.031). 4. In conclusion, patients with mild and moderate LC have reduced exercise capacity, which correlates with Child-Pugh score, as well as reduced chronotropic index and prolonged recovery oxygen uptake kinetics. The results suggest worsened ventilatory efficiency during exercise and cardiopulmonary reasons for the higher SMEPS in these patients.

Six Minute Walk Test to assess functional capacity in chronic liver disease patients

AIM: To examine the utility of Six Minute Walk Test (6MWT) in patients with chronic liver disease (CLD).

METHODS: Two hundred and fifty subjects between the ages of 18 and 80 (mean 47) years performed 6MWT and the Six Minute Walk Distance (6MWD) was measured.

RESULTS: The subjects were categorized into four groups. Group A (n = 45) healthy subjects (control); group B (n = 49) chronic hepatitis B patients; group C (n = 54) chronic hepatitis C patients; group D (n = 98) liver cirrhosis patients. The four groups differed in terms of 6MWDs (P < 0.001). The longest distance walked was 421 ± 47 m by group A, then group B (390 ± 53 m), group C (357 ± 72 m) and group D (306 ± 111 m). The 6MWD correlated with age (r = -0.482, P < 0.01), hemoglobin (r = +0.373, P < 0.001) and albumin (r = +0.311, P < 0.001) levels. The Child-Pugh classification was negatively correlated with the 6MWD in cirrhosis (group D) patients (r = -0.328, P < 0.01). At the end of a 12 mo follow-up period, 15 of the 98 cirrhosis patients had died from disease complications. The 6MWD for the surviving cirrhotic patients was longer than for non-survivors (317 ± 101 vs 245 ± 145 m, P = 0.021; 95% CI 11-132). The 6MWD was found to be an independent predictor of survival (P = 0.024).

CONCLUSION: 6MWT is a useful tool for assessing physical function in CLD patients. We suggest that 6MWD may serve as a prognostic indicator in patients with liver cirrhosis.

Cirrhotic cardiomyopathy

Decompensated liver cirrhosis is characterized by a peripheral vasodilation with a low-resistance hyperdynamic circulation. The sustained increase of cardiac work load associated with such a condition may result in an inconstant and often subclinical series of heart abnormalities, constituting a new clinical entity known as "cirrhotic cardiomyopathy". Cirrhotic cardiomyopathy is variably associated with baseline increase in cardiac output, defective myocardial contractility and lowered systo-diastolic response to inotropic and chronotropic stimuli, down-regulated beta-adrenergic function, slight histo-morphological changes, and impaired electric "recovery" ability of ventricular myocardium. Cirrhotic cardiomyopathy is usually clinically latent or mild, likely because the peripheral vasodilation significantly reduces the left ventricle after-load, thus actually "auto-treating" the patient and masking any severe manifestation of heart failure. In cirrhotic patients, the presence of cirrhotic cardiomyopathy may become unmasked and clinically evident by certain treatment interventions that increase the effective blood volume and cardiac pre-load, including surgical or transjugular intrahepatic porto-systemic shunts, peritoneo-venous shunts (LeVeen) and orthotopic liver transplantation. Under these circumstances, an often transient overt congestive heart failure may develop, with increased cardiac output as well as right atrial, pulmonary artery and capillary wedge pressures.

Physical fitness, fatigue, and quality of life after liver transplantation

Fatigue is often experienced after liver transplantation. The aims of this cross-sectional study were to assess physical fitness (cardiorespiratory fitness, neuromuscular fitness, body composition) in liver transplant recipients and to explore whether physical fitness is related to severity of fatigue. In addition, we explored the relationship between physical fitness and health-related quality of life. Included were 18 patients 1-5 years after transplantation (aged 48.0 +/- 11.8 years) with varying severity of fatigue. Peak oxygen uptake during cycle ergometry, 6-min walk distance, isokinetic muscle strength of the knee extensors, body mass index, waist circumference, skinfold thickness, severity of fatigue, and health-related quality of life were measured. Cardiorespiratory fitness in the liver transplant recipients was on average 16-34% lower than normative values (P Collapse

Key Words

• liver transplantation
• fatigue
• peak oxygen uptake
• isokinetic muscle strength
• body composition

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MESH Headings

• Adult
• Body Composition/physiology
• Cardiovascular Physiological Phenomena
• Cross-Sectional Studies
• Fatigue/physiopathology
• Female
• Humans
• Liver Transplantation/physiology
• Male
• Middle Aged
• Muscle Strength/physiology
• Oxygen Consumption/physiology
• Physical Fitness/physiology
• Quality of Life
• Respiratory Physiological Phenomena
• Severity of Illness Index

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Affiliation(s)

Berbke T J van Ginneken Department of Rehabilitation Medicine, Erasmus University Medical Center Rotterdam, The Netherlands.
Rita J G van den Berg-Emons
Geert Kazemier
Herold J Metselaar
Hugo W Tilanus
Henk J Stam

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Cardiopulmonary complications in chronic liver disease

Patients with cirrhosis and portal hypertension exhibit characteristic cardiovascular and pulmonary hemodynamic changes. A vasodilatatory state and a hyperdynamic circulation affecting the cardiac and pulmonary functions dominate the circulation. The recently defined cirrhotic cardiomyopathy may affect systolic and diastolic functions, and imply electromechanical abnormalities. In addition, the baroreceptor function and regulation of the circulatory homoeostasis is impaired. Pulmonary dysfunction involves diffusing abnormalities with the development of the hepatopulmonary syndrome and portopulmonary hypertension in some patients. Recent research has focused on the assertion that the hemodynamic and neurohumoral dysregulation are of major importance for the development of the cardiovascular and pulmonary complications in cirrhosis. This aspect is important to take into account in the management of these patients.

Maintained cerebral and skeletal muscle oxygenation during maximal exercise in patients with liver cirrhosis

BACKGROUND/AIMS

In cirrhotic patients, insufficient redistribution of blood from splanchnic organs to the central circulation could limit blood supply to skeletal muscles and the brain during exercise.

METHODS

Eight cirrhotic patients performed incremental cycling to exhaustion (74 (49-123) W; median with range).

RESULTS

Heart rate increased from 68 (62-88)beats/min at rest to 142 (116-163)beats/min, cardiac output from 5.1 (3.3-7.2) to 12.9 (8.5-15.9)l/min, and mean arterial pressure from 89 (75-104) to 115 (92-129)mmHg (P<0.05), while the indocyanine green elimination determined hepatosplanchnic blood flow declined from 0.97 (0.55-1.46) to 0.62 (0.36-1.06)l/min (P<0.05). As assessed by near-infrared spectrophotometry, cerebral oxygenation (NIRS) was 61% (48-85%) and increased to 72% (57-86%) during exercise (P<0.05). The NIRS determined oxygenation of the vastus lateralis muscle also increased: the concentrations of oxygenated haemoglobin by 5.9 (0.57-9.47)micromol/l, deoxygenated haemoglobin by 7.2 (1.8-12.0)micromol/l, and thus total haemoglobin by 12.1 (3.6-21.5)micromol/l (P<0.05).

CONCLUSIONS

In patients with cirrhosis, exercise reduces hepatosplanchnic blood flow, while O(2) supply to muscle and brain appears to increase indicating that blood redistribution from splanchnic organs does not limit blood flow to working muscles and the brain.

IgG from patients with liver diseases inhibit mitochondrial respiration in permeabilized oxidative muscle cells: impaired function of intracellular energetic units?

The effect of IgG purified from the sera of healthy persons and patients with primary biliary cirrhosis (PBC) and chronic hepatitis (CH) on ADP dependent respiration (oxidative phosphorylation) in skinned muscle fibers from rat oxidative muscles (heart and M. soleus) and glycolytic skeletal muscle (M. gastrocnemius) was studied. The results show that IgG from three different sources inhibited the rate of respiration by 13, 44 and 42%, respectively, these effects being equally expressed in both types of oxidative muscles, whereas no inhibition was observed in glycolytic muscle. The following washout of unbound IgG did not abolish the inhibition of respiration suggesting that the specific interaction of IgG with antigens had taken place. Laser confocal analysis revealed binding of IgG predominantly to the sarcomeric structures such as Z-disk and M-lines in the cardiomyocytes. The staining of IgG within Z-disks and intermitochondrial space coincided throughout the muscle cells so that transversally serial spaces, each containing mitochondria and adjacent sarcomere, became clearly visible. When the IgG from a CH patient was incubated with the skinned myocardial fibers of the desmin knockout mice, its binding to Z-disks and the sarcomeric area was found to be similar to that in normal cardiac muscle. However, the transversal staining pattern was disintegrated, because of the slippage of the myofibrils in relation to each other and accumulation of mitochondria between them. These observations support the recent hypothesis that in oxidative muscles the mitochondria and adjacent sarcomeres form complexes, termed as the intracellular energetic units, ICEUs. Moreover, they indicate that human autoantibodies can be useful tools for localizing the proteins responsible for formation of ICEUs and modulation of their function. Thus, it appears that the proteins associated with the Z-disks and M-lines may participate in formation of ICEUs and that binding of IgG to these proteins decreases the access of exogenous adenine nucleotides to mitochondria, which manifests as decreased rate of ADP-dependent respiration.

Aerobic capacity is associated with 100-day outcome after hepatic transplantation

The shortage of donor organs highlights the need to better identify patients most likely to benefit from hepatic transplantation. Reduced aerobic capacity (decreased peak oxygen consumption [VO(2)] during symptom-limited cardiopulmonary exercise testing) is frequently present in cirrhosis. Peak VO(2) during cardiopulmonary exercise testing may predict short-term outcome after hepatic transplantation. Symptom-limited testing was performed on a cycle ergometer (continuous ramp protocol) and VO(2) determined using a metabolic cart. One hundred fifty-six patients were tested; 59 subsequently underwent hepatic transplantation. Results showed that survivors and nonsurvivors were similar in age, duration of liver disease, Child-Pugh score, MELD score, resting cardiovascular function, pulmonary function, and gas exchange. The 6 (10.2%) patients dying within 100 days of transplantation were more likely to have reduced aerobic capacity (peak VO(2) <60% predicted and VO(2) at anaerobic threshold [VO(2)-AT] <50% predicted peak VO(2)) compared to survivors (4/6 vs. 7/53, P <.01). Using a multiple logistic regression model controlling for duration and severity of liver disease and time to transplantation, reduced aerobic capacity was independently associated with 100-day mortality. In conclusion, reduced aerobic capacity during cardiopulmonary exercise testing is associated with decreased short-term survival after hepatic transplantation. Further study is needed to determine if cardiopulmonary exercise testing can be used to improve allocation of donor organs. To ensure optimum allocation of donor organs, it is important to identify patients most likely to benefit from transplantation. Investigators have identified a number of preoperative, intraoperative, and postoperative factors that predict increased risk for postoperative mortality. Unfortunately, predictive accuracy has not been high, and the timing of factor identification does not optimize organ utilization. Identification of predictors of survival at the time of listing for transplantation might lead to better resource allocation.

Portopulmonary hypertension: a tale of two circulations

Pulmonary involvement is common in patients with portal hypertension and can manifest in diverse manners. Changes in pulmonary arterial resistance, manifesting either as the hepatopulmonary syndrome or portopulmonary hypertension (PPHTN), have been increasingly recognized in these patients in recent years. This review summarizes the clinicopathologic features, diagnostic criteria, as well as the latest concepts in the pathogenesis and management of PPHTN, which is defined as an elevated pulmonary artery pressure in the setting of an increased pulmonary vascular resistance and a normal wedge pressure in a patient with portal hypertension.

Cirrhotic cardiomyopathy: a pathophysiological review of circulatory dysfunction in liver disease

The systemic circulation in patients with cirrhosis is hyperdynamic with an increased cardiac output and heart rate and a reduced systemic vascular resistance as the most pronounced alterations. The concomitant cardiac dysfunction has recently been termed "cirrhotic cardiomyopathy", which is an entity different from that seen in alcoholic heart muscle disease. Clinically, these patients present with sodium fluid retention and strain often unmasks the presence of latent heart failure. No specific treatment can yet be recommended but caution should be used with respect to procedures that may stress the heart such as shunt implantation and liver transplantation.