Determinants of the renin-angiotensin-aldosterone system in cirrhosis with special emphasis on the central blood volume

Association of Hypoalbuminemia With Clinical Outcomes in Patients Admitted With Acute Heart Failure

Albumin is a protein produced by the liver essential for maintaining blood volume and regulating fluid balance. Hypoalbuminemia is characterized by low levels of albumin in the blood. It is also a marker of malnutrition-inflammatory syndrome. Several studies have demonstrated its prognostic role in patients with chronic heart failure; however, data regarding hypoalbuminemia in acute heart failure admissions are scarce. This study aims to analyze the relationship between hypoalbuminemia and heart failure. We used a retrospective cohort study surveying data from the 2016-2018 combined National Inpatient Sample (NIS) database. Adult hospitalizations for heart failure patients were identified using the ICD-10 codes, stratified into cohorts with and without hypoalbuminemia. Primary outcomes were (1) in-patient mortality, (2) length of stay, and total hospital charge. We also reclassified the HF admissions with hypoalbuminemia to those with systolic or diastolic heart failure to compare any differences in mortality and other in-patient complications. Multivariate linear and logistic regression were used to adjust for confounders and to analyze the outcomes. There were 1,365,529 adult hospitalizations for Congestive Heart Failure (CHF), and among them 1,205,990 (88 %) had secondary diagnoses of hypoalbuminemia. Patients with comorbid hypoalbuminemia were, on average, 8 years older (P < 0.001), predominantly white race, and males (P-value <0.001). HF hospitalizations with hypoalbuminemia had double in-hospital mortality than those without (4.8% vs 2.7%, P < 0.001). However, there was no difference in mortality between patients with Systolic heart failure and Diastolic heart failure with concomitant low albumin levels (from 4.9 % vs 4.7%, P 0.13). We found that patients admitted with HF and concomitant Hypoalbuminemia (HA) had nearly twice the odds of in-patient mortality than those with normal albumin levels. The Length of Stay (LOS) was higher between comparison groups. THC remained statistically indifferent in patients regardless of albumin levels but was greater in hypoalbuminemic patients with Systolic heart failure than Diastolic heart failure ones.

Mechanisms of Acute Right Ventricular Injury in Cardiothoracic Surgical and Critical Care Settings: Part 2

The right ventricle (RV) is intricately linked in the clinical presentation of critical illness; however, the basis of this is not well-understood and has not been studied as extensively as the left ventricle. There has been an increased awareness of the need to understand how the RV is affected in different critical illness states. In addition, the increased use of point-of-care echocardiography in the critical care setting has allowed for earlier identification and monitoring of the RV in a patient who is critically ill. The first part of this review describes and characterizes the RV in different perioperative states. This second part of the review discusses and analyzes the complex pathophysiologic relationships between the RV and different critical care states. There is a lack of a universal RV injury definition because it represents a range of abnormal RV biomechanics and phenotypes. The term "RV injury" (RVI) has been used to describe a spectrum of presentations, which includes diastolic dysfunction (early injury), when the RV retains the ability to compensate, to RV failure (late or advanced injury). Understanding the mechanisms leading to functional 'uncoupling' between the RV and the pulmonary circulation may enable perioperative physicians, intensivists, and researchers to identify clinical phenotypes of RVI. This, consequently, may provide the opportunity to test RV-centric hypotheses and potentially individualize therapies.

Toll-like receptor 4 signaling pathway mediates both liver and kidney injuries in mice with hepatorenal syndrome

Hepatorenal syndrome (HRS) is a complication of cirrhosis with high morbidity and mortality. Nevertheless, the underlying mechanism involving how kidney injury aggravates the progression of cirrhosis remains unclear. This study aims to explore the role of the Toll-like receptor 4 (TLR4) signaling pathway in mediating liver and kidney injuries in HRS mice induced by unilateral ureteral obstruction (UUO) and/or bile duct ligation (BDL). Two weeks after UUO, there were no obvious pathological changes in mouse liver and the unligated side of kidney. Nevertheless, impaired liver and kidney functions, inflammatory response, and fibrosis were examined in mice after 2 wk of BDL. Compared with those of other groups, mice in the BDL + UUO group presented severer liver and kidney injuries, higher levels of inflammatory factors, and faster deposition of collagens, suggesting that kidney injuries accelerated the aggravation of HRS. Correlation analysis identified a positive correlation between expression levels of inflammatory factors and fibrotic levels. Meanwhile, TLR4 and its ligand MyD88 were upregulated during the process of liver and kidney injuries in HRS mice. Further animal experiments in transgenic TLR4^-/- mice or in those treated with TAK242, a small molecule inhibitor of TLR4, showed that blocking the TLR4 signaling pathway significantly improved survival quality and survival rate in HRS mice by alleviating liver fibrosis and kidney injury. It is concluded that kidney dysfunction plays an important role in the aggravation of cirrhosis, which may be attributed to the TLR4 signaling pathway. Targeting TLR4 could be a promising therapeutic strategy for protecting both liver and kidneys in patients with HRS.NEW & NOTEWORTHY Our study established BDL, UUO, and BDL + UUO models, providing a novel idea for analyzing liver and kidney diseases. It is highlighted that the kidney injury accelerated the aggravation of HRS via inflammatory response, which could be protected by inhibiting the TLR4 signaling pathway. We believed that targeting TLR4 was a promising therapeutic strategy for protecting both liver and kidney functions in patients with HRS.

Evaluation of the definition of hyperdynamic circulation in patients with cirrhosis and ascites

The aim of this study was to evaluate potential criteria for defining hyperdynamic circulation in patients with cirrhosis according to the severity of ascites and its association with the activation of vasoactive systems and markers of systemic inflammation. Cross-sectional study of patients with cirrhosis and right heart catheter measurement from two different academic centers. We evaluated systemic vascular resistance (SVR)/cardiac output (CO) according to ascites severity. The first substudy evaluated the possible definition, the second validated the findings, and the third evaluated the possible mechanisms. Comparisons were performed by means of t test, Mann-Whitney U test, and analysis of variance. Finally, linear regression curves were adjusted to evaluate the relationship between CO and SVR according to the severity of ascites and compensated or decompensated stage of cirrhosis. The study included 721 patients (substudy 1, n = 437; substudy 2, n = 197; substudy 3, n = 87). Hyperdynamic circulation (HC), defined by absolute cutoffs, had no association with the presence or severity of ascites in the first two cohorts. No association was observed between HC with renin, aldosterone, or markers of bacterial translocation. Comparison of linear regression curves showed a shift of the CO-SVR relationship to the left in patients with refractory ascites (p < 0.001) compared to patients without ascites as well as to patients with decompensated cirrhosis (p = 0.002). Conclusion: HC according to the traditional concept of high CO and low SVR is not always present in ascites. Evaluation of the CO-SVR relationship according to the severity of ascites shows a shift to the left, suggesting that the presence of HC would be defined by this shift, independent of absolute values.

Practice guidance for the use of terlipressin for liver cirrhosis-related complications

Background

Liver cirrhosis is a major global health burden worldwide due to its high risk of morbidity and mortality. Role of terlipressin for the management of liver cirrhosis-related complications has been recognized during recent years. This article aims to develop evidence-based clinical practice guidance on the use of terlipressin for liver cirrhosis-related complications.

Methods

Hepatobiliary Study Group of the Chinese Society of Gastroenterology of the Chinese Medical Association and Hepatology Committee of the Chinese Research Hospital Association have invited gastroenterologists, hepatologists, infectious disease specialists, surgeons, and clinical pharmacists to formulate the clinical practice guidance based on comprehensive literature review and experts' clinical experiences.

Results

Overall, 10 major guidance statements regarding efficacy and safety of terlipressin in liver cirrhosis were proposed. Terlipressin can be beneficial for the management of cirrhotic patients with acute variceal bleeding and hepatorenal syndrome (HRS). However, the evidence regarding the use of terlipressin in cirrhotic patients with ascites, post-paracentesis circulatory dysfunction, and bacterial infections and in those undergoing hepatic resection and liver transplantation remains insufficient. Terlipressin-related adverse events, mainly including gastrointestinal symptoms, electrolyte disturbance, and cardiovascular and respiratory adverse events, should be closely monitored.

Conclusion

The current clinical practice guidance supports the use of terlipressin for gastroesophageal variceal bleeding and HRS in liver cirrhosis. High-quality studies are needed to further clarify its potential effects in other liver cirrhosis-related complications.

Lock, Stock and Barrel: Role of Renin-Angiotensin-Aldosterone System in Coronavirus Disease 2019

Since the end of 2019, the medical-scientific community has been facing a terrible pandemic caused by a new airborne viral agent known as SARS-CoV2. Already in the early stages of the pandemic, following the discovery that the virus uses the ACE2 cell receptor as a molecular target to infect the cells of our body, it was hypothesized that the renin-angiotensin-aldosterone system was involved in the pathogenesis of the disease. Since then, numerous studies have been published on the subject, but the exact role of the renin-angiotensin-aldosterone system in the pathogenesis of COVID-19 is still a matter of debate. RAAS represents an important protagonist in the pathogenesis of COVID-19, providing the virus with the receptor of entry into host cells and determining its organotropism. Furthermore, following infection, the virus is able to cause an increase in plasma ACE2 activity, compromising the normal function of the RAAS. This dysfunction could contribute to the establishment of the thrombo-inflammatory state characteristic of severe forms of COVID-19. Drugs targeting RAAS represent promising therapeutic options for COVID-19 sufferers.

Cardiac baroreflex function and vascular reactivity recovery after aerobic exercise in patients with early cirrhosis

OBJECTIVE

To investigate the effects of aerobic exercise on the cardiac baroreflex function and vascular reactivity in patients with cirrhosis.

METHODS

Thirteen patients with cirrhosis were submitted to exercise and control intervention. At baseline and at 30 and 60 min following intervention, we evaluated cardiac baroreflex sensitivity (cBRS) and the baroreflex effectiveness index (BEI) using sequence technique. Vascular reactivity was assessed inducing reactive hyperemia before and 60 min after intervention.

RESULTS

At baseline, there was no difference (P interaction = 0.848) between exercise (from 3.0 ± 0.34 to 14.60 ± 1.06 ml/100ml/min) and control sessions (from 2.38 ± 0.10 to 13.73 ± 1.05 ml/100ml/min) regarding the increase in forearm blood flow during reactive hyperemia. However, this response was higher postexercise (from 3.38 ± 0.31 to 16.58 ± 1.58 ml/100ml/min) than postcontrol intervention (from 2.04 ± 0.23 to 11.98 ± 1.16 ml/100ml/min, P interaction < 0.001). BEI increased at 30- and 60-min postexercise (from 32 ± 7 to 42 ± 7 and 46 ± 7%), but not after control intervention (from 33 ± 6 to 31 ± 5 and 33 ± 7%, P interaction = 0.014). In contrast, cBRS decreased at 30-min postexercise (from 10.3 ± 1.9 to 8.2 ± 1.4 and 10.3 ± 2.1 ms/mmHg) and increased postcontrol intervention (from 7.9 ± 0.9 to 10.5 ± 1.5 and 10.3 ± 1.3 ms/mmHg, P interaction = 0.012).

CONCLUSION

The results suggest that a single bout of aerobic exercise improved cardiac baroreflex function and increased vascular reactivity in patients with early-stage cirrhosis.

Correlation of Serum Cardiac Markers with Acute Decompensating Events in Liver Cirrhosis

METHODS

Cirrhotic patients who were consecutively hospitalized between January 2016 and March 2019 were screened. Serum cardiac biomarkers at admission, including N-Terminal pro-B-type natriuretic peptide (NT-pro BNP), high-sensitivity cardiac troponin T (hs-cTnT), creatine kinase (CK), creatine kinase MB (CK-MB), and lactate dehydrogenase (LDH), were collected. Acute decompensating events at admission, primarily including ascites, acute gastrointestinal hemorrhage, and acute-on-chronic liver failure (ACLF), were recorded.

RESULTS

The NT-pro BNP level was significantly higher in cirrhotic patients with acute decompensating events than in those without any decompensating events (median: 140.75 pg/mL versus 41.86 pg/mL, P < 0.001). The NT-pro BNP level significantly correlated with ascites, acute gastrointestinal hemorrhage, and ACLF. The hs-cTnT level was significantly higher in cirrhotic patients with acute decompensating events than in those without decompensating events (median: 0.008 ng/mL versus 0.006 ng/mL, P = 0.007). The hs-cTnT level significantly correlated with acute gastrointestinal hemorrhage, but not ascites or ACLF. LDH (185.0 U/L versus 173.5 U/L, P = 0.281), CK (71 U/L versus 84 U/L, P = 0.157), and CK-MB (29.5 U/L versus 33.0 U/L, P = 0.604) levels were not significantly different between cirrhotic patients with and without acute decompensating events.

CONCLUSION

The elevated NT-pro BNP level seems to be closely related to the development of acute decompensating events in liver cirrhosis.

The gut-liver-kidney axis: Novel regulator of fatty liver associated chronic kidney disease

Increased interest in understanding the liver-kidney axis in health and disease during the last decade unveiled multiple recent evidence that suggested a strong association of fatty liver diseases with chronic kidney disease (CKD). Low-grade systemic inflammation is thought to be the major contributing factor to the pathogenesis of CKD associated with fatty liver. However, other contributing factors largely remained unclear, for example, gut microbiota and intestinal barrier integrity. Homeostasis of the gut microbiome is very crucial for the health of an individual. Imbalance in the gut microbiota leads to various diseases like fatty liver disease and CKD. On the contrary, disease conditions can also distinctly change gut microbiota. In this review, we propose the pathogenic role of the gut-liver-kidney axis in the development and progression of CKD associated with chronic fatty liver diseases, either non-alcoholic fatty liver disease or non-alcoholic steatohepatitis in experimental models and humans. Further, we discuss the therapeutic potential and highlight the future research directions for therapeutic targeting of the gut-liver-kidney axis.

Liver cirrhosis and left ventricle diastolic dysfunction: Systematic review

BACKGROUND

Liver cirrhosis is a chronic hepatic disease which is associated with cardiovascular abnormalities. Hyperdynamic circulation in liver cirrhosis causes functional and structural cardiac alterations. The prevalence of left ventricle diastolic dysfunction (LVDD) in cirrhotic patients ranges from 25.7% to as high as 81.4% as reported in different studies. In several studies the severity of diastolic dysfunction (DD) correlated with a degree of liver failure and the rate of dysfunction was higher in patients with decompensated cirrhosis compared with compensated. Future directions of comprehensive assessment of cardiac function in cirrhotic patients might provide a better prognosis for these patients.

AIM

To clarify the correlation between the severity of liver cirrhosis and left ventricle diastolic dysfunction in the existing literature.

METHODS

Through January and February of 2019 at Vilnius University we conducted a systematic review of the global existing literature on the prevalence of left ventricle diastolic dysfunction in patients with liver cirrhosis. We searched for articles in PubMed, Medline and Web of science databases. Articles were selected by using adequate inclusion and exclusion criteria. Our interest was the outcome of likely correlation between the severity of cirrhosis [evaluated by Child-Pugh classes, Model For End-Stage Liver Disease (MELD) scores] and left ventricle diastolic dysfunction [classified according to American Society of Echocardiography (ASE) guidelines (2009, 2016)], as well as relative risk of dysfunction in cirrhotic patients. Subgroup analyses were performed to evaluate the ratio and grades of left ventricle diastolic dysfunction with respect to cirrhosis severity.

RESULTS

A total of 1149 articles and abstracts met the initial search criteria. Sixteen articles which met the predefined eligibility criteria were included in the final analysis. Overall, 1067 patients (out of them 723 men) with liver cirrhosis were evaluated for left ventricle diastolic dysfunction. In our systemic analysis we have found that 51.2% of cirrhotic patients had left ventricle diastolic dysfunction diagnosed and the grade 1 was the most prevalent (59.2%, P < 0.001) among them, the grade 3 had been rarely diagnosed - only 5.1%. The data about the prevalence of diastolic dysfunction in cirrhotic patients depending on Child-Pugh Classes was available from 5 studies (365 patients overall) and only in 1 research diastolic dysfunction was found being associated with severity of liver cirrhosis (P < 0.005). We established that diastolic dysfunction was diagnosed in 44.6% of Child-Pugh A class patients, in 62% of Child B class and in 63.3% of Child C patients (P = 0.028). The proportion of patients with higher diastolic dysfunction grades increases in more severe cirrhosis presentation (P < 0.001). There was no difference between mean MELD scores in patients with and without diastolic dysfunction and in different diastolic dysfunction groups. In all studies diastolic dysfunction was more frequent in patients with ascites.

CONCLUSION

This systemic analysis suggests that left ventricle diastolic dysfunction is an attribute of liver cirrhosis which has not received sufficient attention from clinicians so far. Future suggestions of a comprehensive assessment of cardiac function in cirrhotic patients might provide a better prognosis for these patients and give hint for better understanding of the left ventricle diastolic dysfunction pathogenesis in liver cirrhosis.

The pathophysiology of arterial vasodilatation and hyperdynamic circulation in cirrhosis

Patients with cirrhosis and portal hypertension often develop complications from a variety of organ systems leading to a multiple organ failure. The combination of liver failure and portal hypertension results in a hyperdynamic circulatory state partly owing to simultaneous splanchnic and peripheral arterial vasodilatation. Increases in circulatory vasodilators are believed to be due to portosystemic shunting and bacterial translocation leading to redistribution of the blood volume with central hypovolemia. Portal hypertension per se and increased splanchnic blood flow are mainly responsible for the development and perpetuation of the hyperdynamic circulation and the associated changes in cardiovascular function with development of cirrhotic cardiomyopathy, autonomic dysfunction and renal dysfunction as part of a cardiorenal syndrome. Several of the cardiovascular changes are reversible after liver transplantation and point to the pathophysiological significance of portal hypertension. In this paper, we aimed to review current knowledge on the pathophysiology of arterial vasodilatation and the hyperdynamic circulation in cirrhosis.

Renin-angiotensin-aldosterone (RAAS): The ubiquitous system for homeostasis and pathologies

Renin-angiotensin-aldosterone system (RAAS) is a vital system of human body, as it maintains plasma sodium concentration, arterial blood pressure and extracellular volume. Kidney-secreted renin enzyme acts on its substrate to form angiotensin II, a versatile effector peptide hormone. Every organ is affected by RAAS activation and the resultant hypertension, cell proliferation, inflammation, and fibrosis. The imbalance of renin and angiotensin II can result in an overwhelming number of chronic and acute diseases. RAAS is influenced by other enzymes, hormones, pumps and signaling pathways, hence, this review discusses important facets of this system, its crosstalk with other crucial factors like estrogen, thyroid, cortisol, kallikrein-kinin system, Wnt/β-catenin signaling, and sodium-potassium pump. The nexus of RAAS with the above-discussed systems was scantily explored before. So, this review furnishes a new perspective in comprehension of inflammation diseases. It is followed by the formulation of hypotheses, which can contribute to better management of an array of pathologies plaguing mankind. Manipulation of RAAS, by bending it towards ACE2 expression can regulate endocrine functions, which can be critical for a number of pathological management. Dietary intervention can restore RAAS to normalcy.

Transjugular intrahepatic portosystemic shut vs total paracentesis for treatment of refractory ascites in patients with cirrhosis: A meta-analysis

AIM

To evaluate the efficacy and safety of transjugular intrahepatic portosystemic (TIPS) vs total paracentesis (TP) in the treatment of refractory ascites in patients with cirrhosis.

METHODS

PubMed, Web of Science Medline, EMBASE, CNKI, WanFang Database, and Chinese BioMedical Literature Database were searched to retrieve randomized controlled trials (RCTs) that compared TIPS vs TP in the treatment of refractory ascites in patients with cirrhosis. The quality assessment of RCTs and data extraction were conducted by two reviewers independently. Meta-analysis was performed using RevMan5.2 software.

RESULTS

Six studies involving 390 patients (192 cases of TIPS and 198 cases of TP) were included. The meta-analysis showed that compared with TP, TIPS significantly improved liver transplantation-free (LTF) survival (HR = 0.61, P = 0.0009); reduced recurrent ascites (RR = 0.61, P < 0.0001); decreased the levels of renin [weighted mean difference (WMD) = -5.41, P < 0.00001] and aldosterone (WMD = -23.72, P = 0.02) and provided better control of water-sodium retention; and reduced the incidence rate of hepatorenal syndrome (RR = 0.38, P = 0.03). However, TIPS increased the risk of hepatic encephalopathy (RR = 1.81, P = 0.007). No significant differences were found in overall mortality, hospitalization days, the rates of gastrointestinal bleeding and spontaneous bacterial peritonitis, or the effects of treatment on renal and liver function between the two groups.

CONCLUSION

Compared with traditional paracentesis therapy, TIPS increased the risk of hepatic encephalopathy. However, TIPS significantly improved LTF survival, decreased the risk of recurrent ascites, provided better control of water-sodium retention, and prevented the occurrence of hepatorenal syndrome.

Complications of cirrhosis. A 50 years flashback

In patients with cirrhosis and portal hypertension, it is largely the frequency and severity of complications relating to the diseased liver, degree of portal hypertension and hemodynamic derangement that determine the prognosis. It can be considered as a multiple organ failure that apart from the liver involves the heart, lungs, kidneys, the immune systems and other organ systems. Progressive fibrosis of the liver and subsequent metabolic impairment leads to a systemic and splanchnic arteriolar vasodilatation. With the progression of the disease development of portal hypertension leads to formation of esophageal varices and ascites. The circulation becomes hyperdynamic with cardiac, pulmonary as well as renal consequences for dysfunction and reduced survival. Infections and a changed cardiac function known as cirrhotic cardiomyopathy may be involved in further aggravation of other complications such as renal failure precipitating the hepatorenal syndrome. Patients with end-stage liver disease and related complications as for example the hepatopulmonary syndrome can only radically be treated by liver transplantation.

Reactive oxygen species are involved in regulating hypocontractility of mesenteric artery to norepinephrine in cirrhotic rats with portal hypertension

Background: Oxidative stress is involved in the hypocontractility of visceral artery to vasoconstrictors and formation of hyperdynamic circulation in cirrhosis with portal hypertension. In the present study, we investigated the effect of reactive oxygen species (ROS) on the mesenteric artery contractility in CCl₄-induced cirrhotic rats, and the roles of G protein-coupled receptors (GPCRs) desensitization and RhoA /Rho associated coiled-coil forming protein kinase (ROCK) pathways.

Methods: The mesenteric artery contraction to norepinephrine (NE) was determined by vessel perfusion system following treatments with apocynin, tempol or PEG-catalase. The protein expression of α1 adrenergic receptor, β-arrestin-2, ROCK-1, moesin and p-moesin was measured by western blot. The interaction between α1 adrenergic receptor and β-arrestin-2 was assessed by co-immunoprecipitation.

Results: Pretreatment with apocynin or PEG-catalase in cirrhotic rats, the hydrogen peroxide level in the mesenteric arteriole was significantly decreased, and the dose-response curve of mesenteric arteriole to NE moved to the left with EC₅₀ decreased. There was no significant change for the expression of α1 adrenergic receptor. However, the protein expression of β-arrestin-2 and its affinity with α1 adrenergic receptor were significantly decreased. The ROCK-1 activity and anti- Y-27632 inhibition in cirrhotic rats increased significantly with the protein expression unchanged. Such effects were not observed in tempol-treated group.

Conclusion: The H₂O₂ decrease in mesenteric artery from rats with cirrhosis resulted in down regulation of the β-arrestin-2 expression and its binding ability with α1 adrenergic receptor, thereby affecting the agonist-induced ROCK activation and improving the contractile response in blood vessels.

Effects of carvedilol and propranolol on circulatory regulation and oxygenation in cirrhosis: a randomised study

BACKGROUND AND AIMS

Newer studies suggest that carvedilol, a beta-blocker with a moderate anti-alpha-1 activity, is superior to propranolol in reducing the portal pressure and risk of variceal bleeding. The effect on arterial blood pressure is a matter of concern especially in decompensated patients.

AIMS

to assess potential differential effects of beta-blockers and beta-blockers with moderate anti-alpha-1 activity on selected haemodynamic, humoral, and respiratory characteristics in cirrhosis.

METHODS

Patients with cirrhosis and portal hypertension were randomised to receive carvedilol (n=16) or propranolol (n=13). Cardiac, systemic and splanchnic parameters along with oxygen saturation and plasma renin were measured at inclusion and after 3 months.

RESULTS

Arterial blood pressure, heart rate, and cardiac output decreased equally, central circulation time and systemic vascular resistance increased significantly but similarly. Central blood volume, plasma volume and arterial compliance were unaltered. The QTc interval and renin levels decreased in the carvedilol group, however not significantly different from the propranolol group. Arterial oxygen saturation and alveolar arterial oxygen gradient remained constant in both groups. Hepatic venous pressure gradient decreased equally in the carvedilol and propranolol groups (-17% and -20%, non significant).

CONCLUSIONS

Systemic haemodynamics and pulmonary effects of carvedilol and propranolol are modest and this study could not demonstrate any significant difference between the two treatments.

Cardiac sympathetic imaging with mIBG in cirrhosis and portal hypertension: relation to autonomic and cardiac function

Autonomic and cardiac dysfunction is frequent in cirrhosis and includes increased sympathetic nervous activity, impaired heart rate variability (HRV), and baroreflex sensitivity (BRS). Quantified (123)I-metaiodobenzylguanidine (mIBG) scintigraphy reflects cardiac noradrenaline uptake, and in patients with cardiac failure it predicts outcome. In this study, we aimed to investigate cardiac sympathetic neuronal function in cirrhosis by mIBG scintigraphy in relation to cardiovascular function. Ten patients with alcoholic cirrhosis and 10 age- and sex-matched healthy controls participated in the study. Heart/mediastinum (H/M) ratios of mIBG uptake were calculated 15 and 230 min after intravenous injection of mIBG. Furthermore, washout rate (WOR) of mIBG was calculated. The patients underwent a liver vein catheterization with determination of splanchnic and systemic hemodynamics and measurement of HRV and BRS. mIBG-scintigraphy revealed significantly increased WOR in patients with cirrhosis compared with controls (P < 0.005), whereas H/M uptakes were equal in the groups. Forty percent of the patients had reduced uptake of mIBG in the infero-lateral segment of the left ventricle. WOR correlated significantly with central circulation time, an estimate of central hypovolemia (r = -0.64, P < 0.05) and frequency-corrected QT(F) interval (r = 0.71, P = 0.01). Patients with cirrhosis had significantly decreased HRV and BRS correlating with indicators of abnormal cathecholamine uptake by mIBG although the catecholamine level was normal in the patients. In conclusion, in alcoholic cirrhosis, mIBG scintigraphy reveals autonomic dysfunction and impaired myocardial distribution of sympathetic nervous activity. It is associated to indicators of central hypovolemia, QT interval, and decreased HRV and BRS. Measurement of myocardial catecholamine uptake by mIBG may add important information on autonomic and cardiac dysfunction in cirrhosis.

Circulating nitric oxide products do not solely reflect nitric oxide release in cirrhosis and portal hypertension

BACKGROUND

Patients with cirrhosis often develop a systemic vasodilatation and a hyperdynamic circulation with activation of vasoconstrictor systems such as the renin-angiotensin-aldosterone system (RAAS), and vasopressin. Increased nitric oxide (NO) synthesis has been implicated in the development of this state of vasodilation and pulmonary dysfunction including increased exhaled NO concentrations. Circulating metabolites (NO(x)) may affect the systemic and pulmonary NO-generation. However, the relations of these abnormalities to the haemodynamic changes remain unclear.

AIMS

The aims of the present study were to measure changes in exhaled NO in relation to circulating NO(x), RAAS, and haemodynamics.

METHODS

Twenty patients (eight child class A and 12 class B patients) underwent a liver vein catheterization with determination of splanchnic and systemic haemodynamics. Circulating NO(x) and exhaled NO were determined in the supine and sitting positions and related to haemodynamics, RAAS and lung diffusing capacity (D(L)CO). Eight matched healthy individuals served as controls.

RESULTS

All patients with cirrhosis had portal hypertension. We found no significant difference in exhaled NO between patients and controls and no changes from the supine to the sitting position. Exhaled NO in the patients correlated significantly with plasma volume, heart rate and D(L)CO. NO(x) concentrations were not significantly increased in the patients. NO(x) correlated with portal pressure and haemodynamic indicators of vasodilatation, but not with exhaled NO concentrations.

CONCLUSION

In patients with moderate cirrhosis, exhaled NO is normal. Circulating NO(x) do not seem to reflect pulmonary and systemic NO release, but NO(x) seems to reflect systemic and splanchnic haemodynamic changes in cirrhosis.

Reduced baroreflex sensitivity and pulmonary dysfunction in alcoholic cirrhosis: effect of hyperoxia

Patients with cirrhosis exhibit impaired regulation of the arterial blood pressure, reduced baroreflex sensitivity (BRS), and prolonged QT interval. In addition, a considerable number of patients have a pulmonary dysfunction with hypoxemia, impaired lung diffusing capacity (Dl(CO)), and presence of hepatopulmonary syndrome (HPS). BRS is reduced at exposure to chronic hypoxia such as during sojourn in high altitudes. In this study, we assessed the relation of BRS to pulmonary dysfunction and cardiovascular characteristics and the effects of hyperoxia. Forty-three patients with cirrhosis and 12 healthy matched controls underwent hemodynamic and pulmonary investigations. BRS was assessed by cross-spectral analysis of variabilities between blood pressure and heart rate time series. A 100% oxygen test was performed with the assessment of arterial oxygen tensions (Pa(O(2))) and alveolar-arterial oxygen gradient. Baseline BRS was significantly reduced in the cirrhotic patients compared with the controls (4.7 +/- 0.8 vs. 10.3 +/- 2.0 ms/mmHg; P < 0.001). The frequency-corrected QT interval was significantly prolonged in the cirrhotic patients (P < 0.05). There was no significant difference in BRS according to presence of HPS, Pa(O(2)), Dl(CO), or Child-Turcotte score, but BRS correlated with metabolic and hemodynamic characteristics. After 100% oxygen inhalation, BRS and the QT interval remained unchanged in the cirrhotic patients. In conclusion, BRS is significantly reduced in patients with cirrhosis compared with controls, but it is unrelated to the degree of pulmonary dysfunction and portal hypertension. Acute hyperoxia does not significantly revert the low BRS or the prolonged QT interval in cirrhosis.

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.

Cardiac and systemic haemodynamic complications of liver cirrhosis

Cardiovascular complications of liver cirrhosis include cardiac dysfunction and abnormalities in the central-, splanchnic,- and peripheral circulation. Vasodilatation prevails, but vascular beds with various degrees of reduced and increased haemodynamic resistance are the results of massive activation of powerful homeostatic, regulatory systems. Cirrhotic cardiomyopathy implies systolic and diastolic dysfunction and electrophysiological abnormalities, an entity that is different from alcoholic heart muscle disease. Being often clinical latent, cirrhotic cardiomyopathy can be unmasked by physical and pharmacological strain. Cardiac failure is an important cause of mortality after liver transplantation and stressful procedures as insertions of transjugular intrahepatic portal systemic shunt (TIPS), peritoneal venous shunting, and other types of surgery. Improvement of liver function has been shown to reverse the cardiovascular complications. The clinical significance is an important topic for future research. At present, no specific treatment can be recommended, and the cardiac failure in cirrhosis should be treated as in non-cirrhotic patients with sodium restriction, diuretics, and beta-adrenergic blocking agents. Special care should be taken with the use of ACE-inhibitors and angiotensin antagonist in these patients.

Vascular hyporesponsiveness to angiotensin II in rats with CCl(4)-induced liver cirrhosis

BACKGROUND

Portal hypertension is triggered by vasodilation due to impaired contraction of extrahepatic vessels. Angiotensin II type 1 (AT(1)) receptor-induced vasocontraction is mediated by G proteins and may be desensitized by recruitment of beta-arrestin-2 to the receptor. In this study, we analysed the interaction of AT(1) receptors with beta-arrestin-2 in the context of vascular hypocontractility in rats with CCl(4)-induced cirrhosis.

METHODS

Micronodular liver cirrhosis in rats (n = 15) was induced by regular CCl(4) exposure. Age-matched rats (n = 15) served as controls. Contractility of aortic rings was measured by myography. Protein expressions and phosphorylations were assessed by Western blot analysis, and AT(1) receptor interaction with beta-arrestin-2 by co-immunoprecipitation.

RESULTS

Aortic rings from CCl(4) rats were hypocontractile to angiotensin II independent of nitric oxide synthases (Nomega-nitro-l-arginine methyl ester 200 microM). Expression of the AT(1) receptor, Galpha(q/11) and the contraction-mediating effector Rho kinase was similar in aortas from both groups. Expression and AT(1) receptor binding of beta-arrestin-2 were up-regulated in aortas from CCl(4) rats. Stimulation of isolated aortas with exogenous angiotensin II caused recruitment of beta-arrestin-2 in aortas from noncirrhotic rats, but no further interaction of AT(1) receptors with beta-arrestin-2 was found in aortas from CCl(4) rats. While angiotensin II stimulation resulted in Rho kinase activation in aortas from noncirrhotic rats but not in aortas from CCl(4) rats, extracellular signal-regulated kinase activation in response to angiotensin II was observed in aortas from both groups.

CONCLUSIONS

Vascular hyporesponsiveness to angiotensin II in CCl(4) rats is due to enhanced interaction of the AT(1) receptor with beta-arrestin-2 and consecutively changed receptor function.

Hyperreninemic hypoaldosteronism syndrome, plasma concentrations of interleukin-6 and outcome in critically ill patients with liver cirrhosis

OBJECTIVE

To investigate the relation between the adrenal production of gluco- and mineralocorticoids, the inflammatory status and the outcome in critically ill patients with liver cirrhosis.

DESIGN

Prospective descriptive study.

SETTING

Medical intensive care unit (ICU) in a university hospital.

PATIENTS

Fifty consecutive patients with liver cirrhosis.

INTERVENTIONS

A corticotropin stimulation test within 12h following ICU admission. Plasma cortisol concentration was measured before and after the test. Renin and aldosterone concentrations, as well as interleukin-6 (IL-6) level to assess the pro-inflammatory status, were measured only before the test. Impaired adrenal function was defined as cortisol response to the test less than 9microg/dl. Hyperreninemic hypoaldosteronism syndrome was defined as basal renin over aldosterone ratio (RRA) higher than 2.

MEASUREMENTS AND RESULTS

Forty-one (82%) patients had impaired adrenal function, and 26 patients (52%) presented with RRA > 2. Patients with RRA > 2 exhibited greater disease severity and organ dysfunction scores at baseline, higher levels of serum renin and IL-6, and a greater ICU mortality rate, but risk-adjusted mortality rates were not different between the two groups. Renin and IL-6 plasma concentrations were positively correlated. Finally, in a Cox regression analysis, independent predictors of 30-day mortality were hyperreninemic hypoaldosteronism syndrome, IL-6 higher than 400pg/ml and severe renal failure.

CONCLUSIONS

Adrenal dysfunction was common in critically ill cirrhotic patients. Hyperreninemic hypoaldosteronism syndrome was related to a greater pro-inflammatory status and degree of acute organ failure, and was independently associated with a worse prognosis.