Peripheral and cardiovascular autonomic impairment in chronic liver disease: prevalence and relation to hepatic function

Implication of Hypotension in the Pathogenesis of Cognitive Impairment and Brain Injury in Chronic Liver Disease

The incidence of chronic liver disease is on the rise. One of the primary causes of hospital admissions for patients with cirrhosis is hepatic encephalopathy (HE), a debilitating neurological complication. HE is defined as a reversible syndrome, yet there is growing evidence stating that, under certain conditions, HE is associated with permanent neuronal injury and irreversibility. The pathophysiology of HE primarily implicates a strong role for hyperammonemia, but it is believed other pathogenic factors are involved. The fibrotic scarring of the liver during the progression of chronic liver disease (cirrhosis) consequently leads to increased hepatic resistance and circulatory anomalies characterized by portal hypertension, hyperdynamic circulatory state and systemic hypotension. The possible repercussions of these circulatory anomalies on brain perfusion, including impaired cerebral blood flow (CBF) autoregulation, could be implicated in the development of HE and/or permanent brain injury. Furthermore, hypotensive insults incurring during gastrointestinal bleed, infection, or liver transplantation may also trigger or exacerbate brain dysfunction and cell damage. This review will focus on the role of hypotension in the onset of HE as well as in the occurrence of neuronal cell loss in cirrhosis.

Cirrhotic Cardiomyopathy: The Interplay Between Liver and Cardiac Muscle. How Does the Cardiovascular System React When the Liver is Diseased?

It is widely known that liver cirrhosis, regardless of the etiologies is accompanied by severe hemodynamic changes. The principal pathophysiological mechanisms are the hyperdynamic circulation with increased cardiac output, heart rate along with reduced systemic vascular resistance. Thus, counteractive mechanisms may develop that eventually lead to systolic as well as diastolic dysfunction and rhythm disturbances, in order to keep a steady homeostasis in the human body.

Literally, blunted contractile responsiveness to physical or pharmacological stress, impaired diastolic relaxation and electrophysiological changes, primarily QT interval prolongation, do occur progressively in a cirrhotic patient with no known preexisting cardiac disease. This condition is identified as cirrhotic cardiomyopathy (CCM), an entity different from that seen in alcoholic cardiac muscle disease.

For the past decades, clinicians did study and attempt to understand the pathophysiology and clinical significance of this process. Indeed, various factors have been identified acting at the molecular and cellular level.

Electrocardiography, echocardiography and various serum biomarkers are the main tools that help healthcare practitioners to point to the correct diagnosis.

Noteworthy, the subjects that suffer from cirrhotic cardiomyopathy may progress to heart failure during invasive procedures such as surgery, insertion of a transjugular intrahepatic portosystemic shunting (TIPS) and liver transplantation. Besides, several studies have illustrated that CCM is a contributing factor, or even a precipitant, of hepatorenal syndrome (HRS), a conceivable reversible kidney failure in patients with liver cirrhosis and ascites.

The treatment is the same as it is in the patients with liver cirrhosis and heart failure and there is no particular treatment for cirrhotic cardiomyopathy. Hence, it is of utmost importance to clearly comprehend the pathophysiology of this disease in order to design more accurate diagnostic tools and definitive treatments in a way to prevent the complications of cirrhosis and overt heart failure.

The objective of this review is to describe in a comprehensive way the pathological alterations that occur in the cardiovascular system of cirrhotic patients. It will also point the limitations that remain in the diagnosis and treatment strategies and more importantly, this review will alert the clinicians in the modern era to further observe and record additional pathological changes in this subset of patients.

Alcohol-Induced Neuropathy in Chronic Alcoholism: Causes, Pathophysiology, Diagnosis, and Treatment Options

Purpose of the Review

Alcohol abuse causes a wide range of disorders that affect the nervous system. These include confusion, cerebellar ataxia, peripheral neuropathy, and cognitive impairment. Chronic and excessive alcohol consumption is the primary cause of peripheral neuropathy. It is worth noting that peripheral neuropathy has no reliable treatment due to the poor understanding of its pathology.

Recent Findings

Coasting is a major feature of alcoholic neuropathy, largely due to chronic alcohol abuse. Its major features are hyperalgesia, allodynia, and burning pain. Even though much research was done in this area, still we do not have a full understanding of the mechanism of alcoholic neuropathy. However, some theories have been proposed. These include direct or indirect effects of alcohol metabolites, impaired axonal transport, suppressed excitatory nerve pathway activity, or imbalance in neurotransmitters. Activation of spinal cord microglia, mGlu5 spinal cord receptors, and hypothalamic-pituitary-adrenal axis also seem to be implicated in the pathophysiology of this alcoholic neuropathy. The goal of treatment is to impede further damage to the peripheral nerves while also restoring their normal physiology. Alcohol abstinence, intake of balanced diets, and treatment with medications are suggested including benfotiamine, alpha-lipoic acid, acetyl-l-carnitine, vitamin E, methylcobalamin, myo-inositol, N-acetylcysteine, capsaicin, tricyclic antidepressants, or antiepileptic drugs.

Summary

This review focuses on the many pathways that play a role in the onset and development of alcohol-induced neuropathy, as well as present the possible treatment strategies of this disorder, providing insights into a further search of new treatment modalities.

Relationship between Heart Disease and Liver Disease: A Two-Way Street

In clinical practice, combined heart and liver dysfunctions coexist in the setting of the main heart and liver diseases because of complex cardiohepatic interactions. It is becoming increasingly crucial to identify these interactions between heart and liver in order to ensure an effective management of patients with heart or liver disease to provide an improvement in overall prognosis and therapy. In this review, we aim to summarize the cross-talk between heart and liver in the setting of the main pathologic conditions affecting these organs. Accordingly, we present the clinical manifestation, biochemical profiles, and histological findings of cardiogenic ischemic hepatitis and congestive hepatopathy due to acute and chronic heart failure, respectively. In addition, we discuss the main features of cardiac dysfunction in the setting of liver cirrhosis, nonalcoholic fatty liver disease, and those following liver transplantation.

The degree of hepatic steatosis associates with impaired cardiac and autonomic function

BACKGROUND & AIMS

Cardiovascular disease is the principle cause of death in patients with elevated liver fat unrelated to alcohol consumption, more so than liver-related morbidity and mortality. The aim of this study was to evaluate the relationship between liver fat and cardiac and autonomic function, as well as to assess how impairment in cardiac and autonomic function is influenced by metabolic risk factors.

METHODS

Cardiovascular and autonomic function were assessed in 96 sedentary individuals: i) non-alcoholic fatty liver disease (NAFLD) (n = 46, hepatic steatosis >5% by magnetic resonance spectroscopy), ii) Hepatic steatosis and alcohol (dual aetiology fatty liver disease [DAFLD]) (n = 16, hepatic steatosis >5%, consuming >20 g/day of alcohol) and iii) CONTROL (n = 34, no cardiac, liver or metabolic disorders, <20 g/day of alcohol).

RESULTS

Patients with NAFLD and DAFLD had significantly impaired cardiac and autonomic function when compared with controls. Diastolic variability and systolic variability (LF/HF-sBP [n/1]; 2.3 (1.7) and 2.3 (1.5) vs. 3.4 (1.5), p <0.01) were impaired in patients with NAFLD and DAFLD when compared to controls, with DAFLD individuals showing a decrease in diastolic variability relative to NAFLD patients. Hepatic steatosis and fasting glucose were negatively correlated with stroke volume index. Fibrosis stage was significantly negatively associated with mean blood pressure (r = -0.47, p = 0.02), diastolic variability (r = -0.58, p ≤0.01) and systolic variability (r = -0.42, p = 0.04). Hepatic steatosis was independently associated with cardiac function (p ≤0.01); TNF-α (p ≤0.05) and CK-18 (p ≤0.05) were independently associated with autonomic function.

CONCLUSION

Cardiac and autonomic impairments appear to be dependent on level of liver fat, metabolic dysfunction, inflammation and fibrosis staging, and to a lesser extent alcohol intake. Interventions should be sought to moderate the excess cardiovascular risk in patients with NAFLD or DAFLD.

LAY SUMMARY

Increased levels of fat in the liver impair the ability of the cardiovascular system to work properly. The amount of fat in the liver, metabolic control, inflammation and alcohol are all linked to the degree that the cardiovascular system is affected.

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.

Small Intestinal Bacterial Overgrowth in Patients With Cirrhosis

Small intestinal bacterial overgrowth (SIBO) is defined by increased density and/or abnormal composition of microbiota in the small bowel. SIBO is often encountered in patients with cirrhosis as a result of impaired intestinal motility and delayed transit time, both of which are exacerbated by more severe liver disease. Additional risk factors for SIBO commonly encountered in cirrhotic patients include coexisting diabetes, autonomic neuropathy, and/or alcoholic use. Diagnosis of SIBO is performed by breath testing or jejunal aspiration, the gold standard. In cirrhotic patients, the presence of SIBO can lead to profound clinical consequences. Increased intestinal permeability in these patients predisposes to bacterial translocation into the systemic circulation. As a result, SIBO is implicated as a significant risk factor in the pathogenesis of both spontaneous bacterial peritonitis and hepatic encephalopathy in cirrhotics. Antibiotics, especially rifaximin, are the best studied and most effective treatment options for SIBO. However, prokinetics, probiotics, nonselective beta-blockers, and treatment of underlying liver-related pathophysiology with transjugular intrahepatic portosystemic shunt placement or liver transplantation are also being investigated. This review will discuss the risk factors, diagnosis, manifestations in cirrhosis, and treatment options of SIBO.

Reduced neural baroreflex sensitivity is related to enhanced endothelial function in patients with end-stage liver disease

OBJECTIVES

Reduced baroreflex sensitivity (BRS) is a frequent complication in end-stage liver disease, but the underlying mechanism is unknown. We investigated the mechanical and neural components of BRS. Increased nitric oxide (NO) production has been reported in end-stage liver failure. Based on earlier experiments, we hypothesised that enhanced endothelial function might affect baroreflex function. Therefore, we explored the relation between endothelial function and the components of BRS.

MATERIALS AND METHODS

We enrolled 24 patients and 23 controls. BRS was determined by the spontaneous sequence method. Mechanical component was characterised by the distensibility coefficient (DC) of common carotid artery. Neural component was estimated as the ratio of integrated BRS and DC. Endothelial function was quantified by flow-mediated dilation (FMD) of the brachial artery.

RESULTS

Integrated BRS was reduced in patients [7.00 (5.80-9.25) vs. 11.1 (8.50-14.80) ms/mmHg]. The mechanical component was not different in the two groups, whereas neural component showed significant reduction in patients (3.54 ± 1.20 vs. 4.48 ± 1.43 ms/10^-3). FMD was higher in patients (9.81 ± 3.77 vs. 5.59 ± 1.36%). FMD and neural BRS were directly related in controls (r = 0.62), but inversely related in patients (r = -0.49).

CONCLUSIONS

Baroreflex impairment in end-stage liver disease might be explained by deterioration of the neural component, while the mechanical component appears to be preserved. Endothelial NO may enhance BRS in health; however, central endothelial overproduction of NO likely contributes to the reduction of neural component of BRS in patients awaiting liver transplantation.

The role of autonomic dysfunction in cirrhotic patients before and after liver transplantation. Review of the literature

In patients affected by hepatic cirrhosis, autonomic dysfunction is a common finding; usually it is asymptomatic but it may correlate with increased mortality and morbidity before, during and after liver transplant, due to hemodynamic instability in the course of stressful events like sepsis, gastrointestinal bleeding and reperfusion after transplantation surgery. Hyperdynamic circulation and hepatic dysfunction seem to play a role in the pathogenesis of autonomic dysfunction, even if pathophysiological mechanisms are not completely known. We present a revision of previous literature about prevalence, pathophysiological mechanisms, clinical features, and mortality and morbidity of autonomic dysfunction secondary to hepatic cirrhosis.

Decreased excitability and voltage-gated sodium currents in aortic baroreceptor neurons contribute to the impairment of arterial baroreflex in cirrhotic rats

Cardiovascular autonomic dysfunction, which is manifested by an impairment of the arterial baroreflex, is prevalent irrespective of etiology and contributes to the increased morbidity and mortality in cirrhotic patients. However, the cellular mechanisms that underlie the cirrhosis-impaired arterial baroreflex remain unknown. In the present study, we examined whether the cirrhosis-impaired arterial baroreflex is attributable to the dysfunction of aortic baroreceptor (AB) neurons. Biliary and nonbiliary cirrhotic rats were generated via common bile duct ligation (CBDL) and intraperitoneal injections of thioacetamide (TAA), respectively. Histological and molecular biological examinations confirmed the development of fibrosis in the livers of both cirrhotic rat models. The heart rate changes during phenylephrine-induced baroreceptor activation indicated that baroreflex sensitivity was blunted in the CBDL and TAA rats. Under the current-clamp mode of the patch-clamp technique, cell excitability was recorded in DiI-labeled AB neurons. The number of action potential discharges in the A- and C-type AB neurons was significantly decreased because of the increased rheobase and threshold potential in the CBDL and TAA rats compared with sham-operated rats. Real-time PCR and Western blotting indicated that the NaV1.7, NaV1.8, and NaV1.9 transcripts and proteins were significantly downregulated in the nodose ganglion neurons from the CBDL and TAA rats compared with the sham-operated rats. Consistent with these molecular data, the tetrodotoxin-sensitive NaV currents and the tetrodotoxin-resistant NaV currents were significantly decreased in A- and C-type AB neurons, respectively, from the CBDL and TAA rats compared with the sham-operated rats. Taken together, these findings implicate a key cellular mechanism in the cirrhosis-impaired arterial baroreflex.

Peculiar characteristics of portal-hepatic hemodynamics of alcoholic cirrhosis

Alcohol-related cirrhosis is a consequence of heavy and prolonged drinking. Similarly to patients with cirrhosis of other etiologies, patients with alcoholic cirrhosis develop portal hypertension and the hepatic, splanchnic and systemic hemodynamic alterations that follow. However, in alcoholic cirrhosis, some specific features can be observed. Compared to viral cirrhosis, in alcohol-related cirrhosis sinusoidal pressure is generally higher, hepatic venous pressure gradient reflects portal pressure better, the portal flow perfusing the liver is reduced despite an increase in liver weight, the prevalence of reversal portal blood flow is higher, a patent paraumbilical vein is a more common finding and signs of hyperdynamic circulations, such as an increased cardiac output and decreased systemic vascular resistance, are more pronounced. Moreover, alcohol consumption can acutely increase portal pressure and portal-collateral blood flow. Alcoholic cardiomyopathy, another pathological consequence of prolonged alcohol misuse, may contribute to the hemodynamic changes occurring in alcohol-related cirrhosis. The aim of this review was to assess the portal-hepatic changes that occur in alcohol-related cirrhosis, focusing on the differences observed in comparison with patients with viral cirrhosis. The knowledge of the specific characteristics of this pathological condition can be helpful in the management of portal hypertension and its complications in patients with alcohol-related cirrhosis.

Sympathetic withdrawal is associated with hypotension after hepatic reperfusion

OBJECTIVE

Post-reperfusion syndrome (PRS), severe hypotension after graft reperfusion during liver transplantation, is an adverse clinical event associated with poorer patient outcomes. The purpose of this study was to determine whether alterations in autonomic control in liver transplant recipients prior to graft reperfusion are associated with the subsequent development of PRS.

METHODS

Heart rate variability (HRV), systolic arterial blood pressure (SBP) variability, and baroreflex sensitivity of 218 liver transplant recipients were evaluated using 5 min of ECG and arterial blood pressure signals 10 min before graft reperfusion along with other clinical parameters. Logistic regression analyses were performed to assess predictors of PRS occurrence.

RESULTS

Seventy-seven patients (35 %) developed PRS while 141 did not. There were significant differences in SBP (110 ± 16 vs. 119 ± 16 mmHg, P < 0.001) and the ratio of low frequency power to high frequency power (LF/HF) of HRV (1.0 ± 1.4 vs. 2.1 ± 3.7, P = 0.003) between the PRS group and No-PRS group. In multivariate logistic regression analysis, predictors were LF/HF (odds ratio 0.817, P = 0.028) and SBP (odds ratio 0.966, P < 0.001).

INTERPRETATION

Low LF/HF and SBP measured before hepatic graft reperfusion were significantly correlated with subsequent PRS occurrence, suggesting that sympathovagal imbalance and depressed SBP may be key factors predisposing to reperfusion-related severe hypotension in liver transplant recipients.

No ocular involvement in familial amyloidotic polyneuropathy ATTR V30M domino liver recipients

In many transplantation centers domino liver transplantation is an established procedure, increasing the number of available liver grafts. Increasingly, grafts from familial amyloidotic polyneuropathy (FAP) patients are used. Ocular involvement is a well known manifestation of FAP, and can be vision-threatening. The aim of this study was to evaluate the risk of development of familial amyloidotic polyneuropathy ocular manifestations in domino liver recipients. Forty-four cirrhotic patients submitted to liver transplantation were studied, with an average of 6 years of follow up after the procedure. Twenty two patients had received a liver from a FAP donor (Group 1) and 22 had received a liver from a non-FAP cadaveric donor (Group 2). Both groups were similar for mean age and gender. Routine ophthalmological examinations with particular attention to amyloid deposition in the anterior segment and vitreous, peripheral retina state, lacrimal functions tests (Schirmer and tear break-up time) and pupillometry (dynamic and static) were performed. No statistically significant differences were observed in all studied ophthalmic parameters between the two groups. No FAP related ophthalmic manifestations were detected after 6 years of domino liver transplantation, but further prospective regular ophthalmological examinations are necessary to detect the eventual development of late ocular manifestations.

QT interval prolongation in liver cirrhosis: innocent bystander or serious threat?

The ECG QT interval measures the length of ventricular systole. Its prolongation is essentially caused by a delayed repolarization phase, and is associated with an increased risk of ventricular arrhythmias and sudden death in several congenital and acquired conditions. Abnormalities in cardiac electrophysiology are well documented in patients with liver cirrhosis, and the prolonged QT interval has emerged as the electrophysiological hallmark of cirrhotic cardiomyopathy. This article will focus on: first, the epidemiology of QT interval prolongation in cirrhosis; second, the potential molecular mechanisms responsible for the pathogenesis of this electrophysiological abnormality and the putative role of circulating cardiotoxins; third, its prognostic meaning; and fourth, its clinical relevance, in terms of the association between the presence of a long QT interval and the occurrence of ventricular arrhythmias in cirrhotic patients treated with drugs known to increase the QT length or exposed to stressful conditions, such as liver transplantation, gastrointestinal bleeding and shock.

Autonomic dysfunction in chronic liver disease

It is becoming increasingly clear that quality of life (QOL) is impaired in those with chronic liver disease (CLD). One of the most important contributors to impaired QOL is the symptomatic burden which can range from slight to debilitating. Autonomic dysfunction accounts for a significant proportion of these symptoms, which can be common, non-specific and challenging to treat. Investigating the autonomic nervous system can be straight forward and can assist the clinician to diagnose and treat specific symptoms. Evidence-based treatment options for autonomic symptoms, specifically in CLD, can be lacking and must be extrapolated from other studies and expert opinion. For those with severely impaired quality of life, liver transplantation may offer an improvement; however, more research is needed to confirm this.

Role of small intestinal bacterial overgrowth and delayed gastrointestinal transit time in cirrhotic patients with minimal hepatic encephalopathy

BACKGROUND & AIMS

Minimal hepatic encephalopathy (MHE) is the mildest form in the spectrum of hepatic encephalopathy. This cross-sectional study was carried out to elucidate the role of bacterial overgrowth of the small intestine and delayed intestinal transit among patients with MHE.

METHODS

Two-hundred-thirty patients with cirrhosis were screened; 102 patients (44.4%) who met the eligibility criteria were included in the study. MHE was diagnosed when the psychometric hepatic encephalopathy score was ≤-5. All patients underwent a glucose breath test for small intestinal bacterial overgrowth (SIBO) and lactulose breath test for oro-cecal transit time (OCTT).

RESULTS

Fifty-seven (55.9%) patients with cirrhosis had MHE. Among these patients with MHE, 22 (38.6%) had SIBO, while 4 (8.9%) without MHE had SIBO (p = 0.001). The prevalence of SIBO was higher in patients with CTP classes B and C (69.2%) compared to those in CTP class A (30.8%); p = 0.054. OCTT was significantly prolonged in patients who had SIBO than in those who did not have SIBO (p<0.0001). Univariate analysis demonstrated that increased age, female gender, low educational status, low albumin, presence of SIBO, and prolonged OCTT were associated with the presence of MHE. Multivariate analysis demonstrated SIBO as the only factor associated with MHE.

CONCLUSIONS

Our study conclusively demonstrates high prevalence of SIBO in patients with cirrhosis with MHE. This study gives the rationale of treatment directed against SIBO and gut dysmotility, which may include non-absorbable antibiotics such as rifaximin, probiotics, and prokinetics.

Long-term effect of liver transplantation on cirrhotic autonomic cardiac dysfunction

There is little information on the long-term effect of liver transplantation (LT) on cardiac autonomic dysfunction in cirrhotic patients. We compared cardiac autonomic function before and in the long-term after LT. In a transversal study, we investigated 30 cirrhotics awaiting LT, 15 clinically stable patients 2-6 years after LT and 27 healthy controls. Seven cirrhotic patients were studied before LT, and 6, 12 and 33 months after LT, in a prospective fashion. Cardiac autonomic function was measured by heart rate variability (HRV) analysis during 24-h electrocardiogram recording. In the transversal study, patients with cirrhosis as compared to healthy controls had significantly reduced standard deviation of normal-to-normal RR intervals (SDNN) (p<0.001) and of the square root of the mean of squared differences between adjacent NN intervals (RMS-SD) (p<0.01), while the ratio between low frequency (LF) and high frequency (HF) at night was significantly (p<0.05) increased. Liver transplanted patients had significantly (p<0.001) higher SDNN values than cirrhotics, while RMS-SD and LF/HF at night did not differ. In the prospective study, SDNN progressively increased after LT and was significantly (p<0.05) higher at 12 and 33 months, compared to the pre-operative value. RMS-SD and LF/HF at night did not change after LT. In conclusion, the overall HRV decrease present in cirrhosis, measured by SDNN values, is partially corrected in the long-term after LT. However, parasympathetic impairment, measured by RMS-SD and LF/HF at night, is not affected even in the long-term after operation.

Impact of liver transplantation on rate-corrected QT interval and myocardial function in children with chronic liver disease*

Prolonged QTc interval (>440 ms) is a common abnormality in adult patients with CLD and has been reported to predict patient survival. In this study, 88 children who underwent evaluation for LT, including a 12-lead electrocardiogram and echocardiogram included to determine the frequency of QTc prolongation and related factors in children with CLD and the effect of LT on these factors. Sixty-nine healthy, age- and sex-matched children served as controls. QTc interval was prolonged in 40 CLD patients (45.4%). It was found to be related to PELD score and presence of portal hypertension. Mean QTc was higher in patients who died prior to LT than in the survivors without LT. Mortality risk was increased 3.66-fold in patients with prolonged QTc (p = 0.001, 95% CI: 2-7.2). Cox regression analysis showed that only PELD score was an independent predictor of survival (p = 0.001, beta = -0.41, 95% CI: 5.58-1.82). Five of 48 transplanted children died within three months post-transplant; QTc was not related to post-transplant survival (p = 0.27). QTc normalized in 63.8% patients after LT. After LT, LAD, LVEF, and LVPWT decreased. In conclusion, QTc prolongation is common in children with CLD and associated with high mortality. It may be useful for assessment of the severity of CLD and for the timing for transplantation.

The effect of liver transplantation on autonomic dysfunction in patients with end-stage liver disease

Autonomic dysfunction is a recognized complication of end-stage liver disease (ESLD), but there is little information on how liver transplantation (LT) affects this problem. We sought to prospectively evaluate autonomic function in patients with ESLD before and after LT. Autonomic reflex screen (ARS) was performed on 30 patients with ESLD prior to transplantation. A 10-point composite autonomic score (CAS) was calculated from these data. ARS was repeated after LT, and these scores were compared with the pre-LT ARS. Thirty patients (25 male, 5 female) with cirrhosis that were listed for LT were enrolled in the study and underwent ARS prior to LT. The average age was 55.4 +/- 9.1 years. Indications for LT included hepatitis C virus (14), cryptogenic cirrhosis (5), alcoholic cirrhosis (4), and other (7). The mean native Model for End-Stage Liver Disease (MELD) score at ARS was 17.0 +/- 5.0. Prior to LT, 86.7% of patients had evidence of autonomic dysfunction. Mean CAS was 2.7 +/- 2.2. Sudomotor function was disturbed in 66%, parasympathetic function was disturbed in 57%, and adrenergic function was disturbed in 37%. There was no relationship between pre-LT CAS and age, gender, diabetes, etiology of liver disease, or MELD score. Twenty-one patients (17 male, 4 female) had repeat ARS a mean of 9 +/- 6.2 months after LT. The mean native MELD score at the time of ARS testing was 18.1 +/- 4.3. Mean pre-LT CAS in this group was 3.0 +/- 2.4. Pretransplant CAS was not related to age, gender, diabetes, or MELD score. Autonomic dysfunction improved after LT (CAS pre-LT, 3.0, versus CAS post-LT, 1.9, P = 0.02). There was no relationship between post-LT CAS and age, gender, diabetes, etiology of liver disease, immunosuppression, or type of transplant. In conclusion, autonomic dysfunction is common in patients with ESLD, with over 86% having abnormal testing. Sixty-three percent of patients with cirrhosis with autonomic dysfunction show improvement after LT.

Reduced baroreflex sensitivity in alcoholic cirrhosis: relations to hemodynamics and humoral systems

In cirrhosis, arterial vasodilatation leads to central hypovolemia and activation of the sympathetic nervous and renin-angiotensin-aldosterone systems. As the liver disease and circulatory dysfunction may affect baroreflex sensitivity (BRS), we assessed BRS in a large group of patients with cirrhosis and in controls who were all supine and some after 60 degrees passive head-up and 30 degrees head-down tilting in relation to central hemodynamics and activity of the sympathetic nervous and renin-angiotensin-aldosterone systems. One-hundred and five patients (Child classes A/B/C: 21/55/29) and 25 (n=11 + 14) controls underwent a full hemodynamic investigation. BRS was assessed by cross-spectral analysis of variabilities between blood pressure and heart rate time series. The median BRS was significantly lower in the supine cirrhotic patients, 3.7 (range 0.3-30.7) ms/mmHg than in matched controls (n=11): 14.3 (6.1-23.6) ms/mmHg, P<0.001. A stepwise multiple-regression analysis revealed that serum sodium (P=0.044), heart rate (P=0.027), and central circulation time (P=0.034) independently correlated with BRS. Head-down tilting had no effects on BRS, but, after head-up tilting, BRS was similar in the patients (n=23) and controls (n=14). In conclusion, BRS is reduced in cirrhosis in the supine position and relates to various aspects of cardiovascular dysfunction, but no further reduction was observed in parallel with the amelioration of the hyperdynamic circulation after head-up tilting. The results indicate that liver dysfunction and compensatory mechanisms to vasodilatation may be involved in the low BRS, which may contribute to poor cardiovascular adaptation in cirrhosis.

Higher prevalence and severity of hepatic encephalopathy in patients with HCV cirrhosis and diabetes mellitus: is presence of autonomic neuropathy the missing part of the puzzle?

Hepatic encephalopathy (HE) is a complex and variable neuropsychiatric syndrome that is seen in patients with acute and chronic liver diseases. The presence or severity of HE does not always show a strong and consistent relationship with the severity of liver disease or portal hypertension suggesting that other predisposing or precipitating factors may be involved. In this issue of the journal, it has been suggested that DM may contribute to the presence and severity of HE independent of the severity of liver disease in patients with HCV cirrhosis. This editorial examines the limitations of the study and potential mechanisms that could explain the relationship between DM with HE including the role of autonomic neuropathy.

The relationship of heart rate variability with severity and prognosis of cirrhosis

Many studies have demonstrated that cirrhosis is frequently associated with autonomic dysfunction. The aim of this study was to test autonomic dysfunction in cirrhotic patients by analyzing heart rate variability (HRV), to determine whether or not the degree of autonomic dysfunction is correlated with the severity of disease, and, also, to compare the changes of HRV between survivor and nonsurvivor groups after 2-year follow-up periods. HRV was analyzed using 24-hr ECG recording in 30 cirrhotic patients and 28 normal controls. The changes in HRV parameters including mean normal-to-normal (N-N) interbeat intervals (mean NN), standard deviation of all N-N intervals (SDNN), standard deviation of the average of N-N intervals for each 5-min period over 24 hr (SDANN), root mean square succesive differences (r-MSSD; msec), and percentage of adjacent N-N intervals that are >50 msec apart (pNN50), all as time domain parameters, were evaluated. The cirrhotic patients were also evaluated according to Child-Pugh classification scores as markers of the disease severity. The time-domain measures of HRV in cirrhotic patients were significantly reduced compared with those in the control group (for all parameters; P < 0.001). The severity of disease was associated with reduced HRV measures (for all parameters; P < 0.001). After the 2-year follow-up periods, HRV measurements in cirrhotic patients were significantly much lower in nonsurvivors than in survivors (P < 0.001 for all). We conclude that increasing severity of cirrhosis is associated with a reduction in HRV. This finding may be an indicator of poor prognosis and mortality for cirrhosis.

Autonomic dysfunction and impaired cerebral autoregulation in cirrhosis

Cerebral blood flow autoregulation is lost in patients with severe liver cirrhosis. The cause of this is unknown. We determined whether autonomic dysfunction was related to impaired cerebral autoregulation in patients with cirrhosis. Fourteen patients with liver cirrhosis and 11 healthy volunteers were recruited. Autonomic function was assessed in response to deep breathing, head-up tilt and during 24-h Holter monitoring. Cerebral autoregulation was assessed by determining the change in mean cerebral blood flow velocity (MCAVm, transcranial Doppler) during an increase in blood pressure induced by norepinephrine infusion (NE). The severity of liver disease was assessed using the Child-Pugh scale (class A, mild; class B, moderate; class C, severe liver dysfunction).NE increased blood pressure similarly in the controls (27 (24-32) mmHg) and patients with the most severe liver cirrhosis (Child-Pugh C, 31 (26-44) mmHg, p=0.405 Mann-Whitney). However, the increase in MCAVm was greater in cirrhosis patients compared to the controls (Child-Pugh C, 26 (24-39) %; controls, 3 (-1.3 to 3) %; respectively, p=0.016, Mann-Whitney). HRV during deep breathing was reduced in the cirrhosis patients (Child-Pugh C, 6.0+/-2.0 bpm) compared to the controls (21.7+/-2.2 bpm, p=0.001, Tukey' test). Systolic blood pressure fell during head-up tilt only in patients with severe cirrhosis. Our results imply that cerebral autoregulation was impaired in the most severe cases of liver cirrhosis, and that those with impaired cerebral autoregulation also had severe parasympathetic and sympathetic autonomic dysfunction. Furthermore, the degree of liver dysfunction was associated with increasing severity of autonomic dysfunction. Although this association is not necessarily causal, we postulate that the loss of sympathetic innervation to the cerebral resistance vessels may contribute to the impairment of cerebral autoregulation in patients with end-stage liver disease.

Spontaneous baroreflex cardiac sensitivity in end-stage liver disease: effect of liver transplantation

BACKGROUND AND OBJECTIVE

End-stage liver disease is associated with an imbalance in the autonomic nervous system. The purpose of this study was to estimate the effect of liver transplantation on this imbalance.

METHOD

The study involved 10 patients undergoing liver transplantation and 9 patients without liver impairment undergoing liver surgery. The spontaneous baroreflex sensitivity was measured before and 1 month after surgery for the liver surgery group; before and 1, 3, 6, 12 and 18 months after orthotopic liver transplantation.

RESULTS

The spontaneous baroreflex slope of patients with end-stage liver disease was decreased before liver transplantation compared to the liver surgery group (3.9 +/- 2.5 ms mmHg(-1) vs. 9.9 +/- 5.0 ms mmHg(-1), P = 0.002). The mean slope was significantly increased at 12 and 18 months compared to the pre-transplantation value (3.9 +/- 2.5 ms mmHg(-1) vs. 8.1 +/- 6.6 ms mmHg(-1) and 7.4 +/- 4.8 ms mmHg(-1), respectively; P = 0.042). Nevertheless, further analysis of individual data showed that only four patients exhibited a marked increase in their baroreflex slope 12 months after the liver transplantation whereas it remained decreased in the six others.

CONCLUSIONS

These results confirm that the baroreflex sensitivity is depressed in end-stage liver disease in line with an autonomic nervous system imbalance. The liver transplantation reverses this disturbance only in some patients.

Autonomic neuropathy may be associated with delayed orocaecal transit time in patients with cirrhosis

Orocaecal transit (OCT) time is delayed in patients with cirrhosis, but the reasons for this remain unclear. We hypothesized that autonomic neuropathy (AN) may explain the delay in OCT.

METHODS

We determined OCT and autonomic function tests (AFT) in 48 patients (Child A-15, B-27, C-6) with cirrhosis of various aetiologies. AFT were categorized as normal, borderline, or abnormal. OCT was measured using the lactulose hydrogen (H2) breath test. OCT was defined as the time from baseline when there was a rise in H2 levels of >20 ppm over baseline or >10 ppm over baseline sustained over 2 consecutive time points.

RESULTS

Based on OCT, patients were separated into those with delayed OCT (>90 min, group I) and normal OCT (< or = 90 min, group II). Mean OCT time of patients in group I was 169.7+/-49.7 min vs. 84.4+/-12.1 min in group II. Baseline clinical characteristics of patients with and without AN, and those with normal and delayed OCT were similar. Presence of mild encephalopathy did not have an effect on OCT. AN was seen more frequently in group I than group II [16/32 (50%) vs. 3/16 (19%), p=0.03]. Logistic regression analysis showed that the presence of AN was the only independent variable associated with delayed OCT (OR 7.3, CI 1.3-39.4, p=0.02).

CONCLUSION

Our study showed that the presence of AN was associated with delayed OCT in patients with cirrhosis.

Erectile dysfunction as a sentinel symptom of cardiovascular autonomic neuropathy in heavy drinkers

Because autonomic neuropathy (AN) is not routinely assessed in chronic alcoholism, its features and relationship with other disease parameters remain undefined. The very existence of true alcohol-related autonomic dysfunction, in the absence of alcoholic hepatopathy, is even controversial. We aimed this study at evaluating the frequency and pattern of AN in a population of heavy drinkers without liver dysfunction. We also investigated the putative risk factors for AN as well as its relationship to peripheral neuropathy (PN). Autonomic function was evaluated in 70 detoxified alcoholics and 70 well-matched controls by heart-rate response to deep breathing, heart-rate response to standing from lying position, and blood pressure response to standing up. PN was assessed by electroneurography (ENG). Detailed information about sensorimotor and autonomic symptoms, nutritional status, and parameters reflecting alcohol intake were recorded. No patients showed signs of caloric/protein malnutrition. PN was found in 74% and AN (abnormal test results in two of three tests performed) in 26%; abnormalities in at least one autonomic test were found in 62%. All patients with PN were symptomatic, mainly due to sensory disturbances. In line with this, ENG abnormalities were more evident at sural nerves. AN was symptomatic in 10 of 18 patients, and its sole clinical expression was impotence: indeed, the pattern of autonomic involvement was mainly parasympathetic. AN did not correlate with PN, nor with any parameter reflecting the amount of alcohol intake; only performances on heart-rate response to standing from lying position were related to the duration of abuse. The lack of correlation between PN and AN may suggest a different pathophysiology for these two complications. Unlike PN, AN is often asymptomatic. Among symptomatic patients (55%), erectile dysfunction seems to be the sole symptom, in line with the higher degree of parasympathetic damage.

Effects of orthotopic liver transplantation on the corrected QT interval in patients with end-stage liver disease

Autonomic dysfunction is a recognized complication of end-stage liver disease (ESLD) associated with a poor prognosis. The corrected QT interval (QTc) on electrocardiogram is a marker of autonomic function. A few small studies have suggested that QTc may normalize with the return of liver function after orthotopic liver transplantation. We sought to determine how transplantation affects the QTc in patients with ESLD. The QTc from the pretransplantation evaluation of 46 patients with ESLD was compared with the QTc at 4-month posttransplantation follow-up. Other factors that can influence autonomic function also were evaluated. Most patients with ESLD (54%) showed a prolonged QTc (> or = 440 msec) at the pretransplantation evaluation (451 +/- 45 msec) that improved to within the normal range at posttransplantation follow-up (418 +/- 18 msec; P < 0.001). There was no relationship between QTc prolongation and Child-Turcotte-Pugh score, Model for End-Stage Liver Disease score, diabetes mellitus, age, or etiology of liver disease. Most patients with ESLD and a prolonged QTc will have a significant improvement in QTc after transplantation; however, 6.5% of patients in our study had a worsening of QTc after transplantation.

Effects of obstructive jaundice on the peripheral nerve: an ultrastructural study in rats

Obstructive jaundice (OJ) and hepatic disorders have been shown to be associated with peripheral neuropathy in several clinical studies. The study evaluated the effect of OJ on the ultrastructure of the rat sciatic nerve. In the OJ group, jaundice was created by ligation of common bile duct in Wistar-Albino rats. In the sham-operated control group the same procedure was performed without ligation of the bile duct. On day 7, all rats were re-operated and sciatic nerves were explored to harvest 2-cm-long nerve segments for quantitative and qualitative histopathological analysis by light and electron microscopy. Bilirubin was measured on serum samples. Bilirubin levels were significantly higher in jaundiced rats compared with that of controls (8.46 +/- 0.45 vs. 0.80 +/- 0.14 mmol/l, means +/- SD, p < 0.01). Control nerves did not show anything other than the normal histology. In the OJ group, degenerative changes such as irregularities, thinning, ruffling and invaginations, irregularshaped bodies, vacuolizations and focal segmental demyelination were observed in the myelin sheath. Myelin clusters were noted in the axoplasm. A varying degree of swelling was noted in the nucleus and cytoplasm of the Schwann cells. Morphometric analysis of specimens obtained from sciatic nerves showed that myelin injury (370.9 +/- 51.3 vs. 11.6 +/- 0.5 axons), axonal edema (142.1 +/- 24.2 vs. 10.6 +/- 0.5 edematous axons) and Schwann cell degeneration (50.3 +/- 11.6 vs. 3.2 +/- 0.2 Schwann cells) was significantly higher in the jaundiced rats than in the control group (p < 0.01). The ultrastructural alterations spotted in the rat peripheral nerve were attributed to hyperbilirubinemia and increased concentrations of several neurotoxic substances released from the Kupffer cells in OJ. Neuropathy in jaundiced patients seems to result from accompanying degenerative changes in the peripheral nervous system. However, the exact nature and initiating factors of this nerve injury remains to be unveiled.

Systemic, renal, and hepatic hemodynamic derangement in cirrhotic patients with spontaneous bacterial peritonitis

Spontaneous bacterial peritonitis (SBP) is frequently associated with renal failure. This study assessed if systemic and hepatic hemodynamics are also affected by this condition. Standard laboratory tests, tumor necrosis factor alpha (TNF-alpha) in plasma and ascitic fluid, plasma renin activity (PRA) and norepinephrine (NE), and systemic and hepatic hemodynamics were determined in 23 patients with SBP at diagnosis and after resolution of infection. Eight patients developed renal failure during treatment. At diagnosis of infection, patients developing renal failure showed significantly higher values of TNF-alpha, blood urea nitrogen (BUN), PRA and NE, peripheral vascular resistance, and hepatic venous pressure gradient (HVPG) and lower cardiac output than patients not developing renal failure. During treatment, a significant reduction in cardiac output and arterial pressure and increase in PRA and NE, HVPG, and Child-Pugh score were observed in the first group but not in the second. Peripheral vascular resistance remained unmodified in both groups. Changes in PRA and NE correlated inversely with changes in arterial pressure and directly with changes in BUN, Child-Pugh score, and HVPG. Five patients in the renal failure group developed encephalopathy, and 6 died. In the group without renal failure, none of the patients developed encephalopathy or expired. In conclusion, patients with SBP frequently develop a rapidly progressive impairment in systemic hemodynamics, leading to severe renal and hepatic failure, aggravation of portal hypertension, encephalopathy, and death. This occurs despite rapid resolution of infection and is associated with an extremely poor prognosis.

Autonomic and peripheral neuropathy in endstage liver disease and following liver transplantation

Severe chronic liver disease may be associated with a peripheral somatic and an autonomic neuropathy. There are only a limited number of reports on the incidence and features of these neuropathies. In addition the effects of liver transplantation on these neuropathies have not been well studied. We examined peripheral somatic and autonomic nerve function in 42 patients with endstage liver disease prior to transplantation and also examined the effect of liver transplantation on these neuropathies in 14 patients. Peripheral somatic neuropathy (93%) and autonomic neuropathy (50%) were common in patients with endstage liver disease and were more frequent than previously reported. Abnormalities improved in some patients after liver transplantation, particularly if there was return of normal hepatic function.

Autonomic neuropathy in end-stage cirrhotic patients and evolution after liver transplantation

Autonomic neuropathy (AN), which is frequently observed in cirrhosis patients, has been associated with a higher mortality. We have prospectively evaluated the prevalence of AN, its relationship with the degree of liver dysfunction and circulatory disturbances, and the evolution of AN after liver transplantation (LT) in 62 end-stage liver cirrhosis patients. AN was evaluated by seven cardiovascular tests assessing sympathetic or parasympathetic function before and 6 months after LT. Patients were classified as showing absent (A), early (E), or definite dysfunction (D). AN appeared in 67.7% of cases (E: 24.2%, D: 43.5%) without relation to liver disease etiology. Parasympathetic dysfunction was more prevalent than sympathetic dysfunction (59.7% vs. 20.9%). AN was significantly related to Child-Pugh score. Hyperdynamic circulation was more marked in the D than the A group as shown by a greater cardiac output (CO)(9 vs. 7.3 L/min) and a lower peripheral resistance (SVR)(666 vs. 866 dyn.s.cm(-5)). Moreover, AN scores significantly correlated with CO and SVR. Overall the prevalence of AN decreased 6 months after LT (67.7% vs 48%) due to a significant reduction in definite AN (43.5 vs. 14.8%; P<.05). AN improved in 70% of cases after LT. Sympathetic dysfunction remained in only one patient. We conclude that AN is frequent in liver transplant candidates; its severity is associated with the degree of liver failure. Systemic circulatory disturbances seem to correlate with the severity of AN. AN is clearly improved by LT. The evaluation of AN may contribute to a better selection of LT recipients.

Prolongation of QTc interval: relationship with etiology and severity of liver disease, mortality and liver transplantation

BACKGROUND

A prolonged QTc interval has been reported in patients with liver disease. The objectives of our study were to determine whether a prolonged QTc interval was an independent predictor of mortality in patients with cirrhosis and to examine the effect of liver transplantation (LT) on QTc interval.

PATIENTS AND METHODS

We retrospectively studied two cohorts of patients - QTc interval was measured in 409 patients (pre-transplant group), and in 162 patients (transplant group) before and 6 months after LT. QT interval (mean) corrected (QTc) for ventricular rate was read from a 12-lead EKG. Patients with known cardiovascular disease or other risk factors that are known to cause a prolonged QTc interval were excluded.

RESULTS

Pre-transplant group. One hundred and sixty-two patients (40%) had a prolonged QTc interval (>440 ms). By binary logistic regression, age (P=0.005), alcoholic cirrhosis (P=0.007) and Child-Pugh scores (P=0.007) were independent predictors of prolonged QTc interval. Sixty-six patients died during a mean follow-up of 8.9 years. Although the Kaplan-Meier survival curve showed a lower survival in patients with a prolonged QTc interval (P=0.03 by log rank test), when survival was adjusted for the Child-Pugh score by Cox regression survival analysis, there were no survival differences in patients with and without prolonged QTc interval. Cox regression analysis showed that the Child-Pugh score (hazard ratio 1.5, CI 1.3-1.6, s<0.001) was the only independent predictor of survival. Transplant group. In this cohort, 91 patients (56%) had prolonged QTc (>440 ms) before LT. Mean QTc improved significantly after LT (429 +/- 29 ms vs. 450 +/- 39 ms P<0.002). Of the 91 patients with prolonged QTc, 50 (55%) normalized, three (3.3%) remained unchanged, 12 (13.3%) showed further prolongation, and 26 (28%) showed improvement but remained above normal limits. An additional nine patients who had normal QTc before LT developed prolonged QTc (>440 ms) after LT.

CONCLUSION

A prolonged QTc interval was common in patients with cirrhosis, but its presence had no independent effect on mortality. Prolonged QTc returns to normal values in about half of the patients after LT, suggesting that liver disease plays a role, but may not be the only factor in the pathogenesis of prolonged QTc.

Peripheral neuropathy in liver cirrhosis

BACKGROUND AND AIMS

Neuropathy in association with chronic liver disease, including cirrhosis, is recognized; however, there are differences in the incidence and type of neuropathy reported. The causal relationship of liver disease to neuropathy has been questioned. This study was designed to evaluate the incidence and character of peripheral neuropathy in patients with liver cirrhosis. The effect of alcohol consumption, severity of liver disease and encephalopathy on the incidence and severity of neuropathy were also studied.

METHODS

Patients having an identifiable cause of peripheral neuropathy, except alcohol, were excluded from the study. Patients with evidence of vitamin B12 deficiency or diabetes were also excluded from the study. In this study, 33 patients with liver cirrhosis were evaluated clinically and electrophysiologically to detect any evidence of peripheral neuropathy. Nerve conduction studies were performed in the upper and lower limbs using surface electrodes. These patients also underwent a detailed clinical examination.

RESULTS

Clinical signs of peripheral neuropathy were found in seven (21%) patients. Nerve conduction studies were abnormal in 24 (73%) patients. The pattern of involvement was predominantly of an axonal sensory motor polyneuropathy. Neuropathy was found both in patients with alcohol-related and non-alcohol-related cirrhosis. The presence of encephalopathy did not have a significant bearing on the incidence and severity of neuropathy. The neuropathy was also not significantly related to the severity of liver disease.

CONCLUSIONS

The present study reveals that a significant number of patients with liver cirrhosis show evidence of peripheral neuropathy, which is present regardless of the etiology of cirrhosis, and is subclinical in a majority of these patients. The cause of neuropathy was probably the liver disease itself, as the incidence and severity of neuropathy in the alcohol-related cirrhosis, although higher, was not significantly different from the neuropathy in patients with non-alcohol-related cirrhosis.

Gastric emptying time and the effect of cisapride in cirrhotic patients with autonomic neuropathy

GOALS To investigate the relationships between gastric emptying and autonomic dysfunction in hepatic cirrhosis and to assess the effects of cisapride on gastric emptying in cirrhotic patients. STUDY Twenty-four cirrhotic patients (8 patients in each Child-Pugh classification) and 25 healthy controls were enrolled. All the patients had viral (B or C) hepatitis. Patients with DM, alcoholic cirrhosis, active peptic ulcer, gastric malignancy and pyloric obstruction were excluded by esophagogastroduodenoscopy. Parasympathetic and sympathetic functions were assessed by the criteria set forth by Ewing and Clark. Drugs affecting GI motility and smoking were discontinued 48 hours and 12 hours prior to the study respectively. A solid-phase of gastric emptying study was conducted by scintigraphic method for the calculation of gastric half-emptying time (GET1/2). RESULTS The study revealed that 9 patients with Child-Pugh B and C cirrhosis had autonomic neuropathy and none of Child-Pugh A cirrhosis had autonomic neuropathy. Prolonged GET1/2 was noted in cirrhotics compared with the control group (p < 0.05). However, there was significant difference between 9 patients (Child B-C) with autonomic neuropathy compared with patients 15 patients without autonomic neuropathy. Again there was a significant difference in GET1/2 between Child A cirrhotic and Child B-C cirrhotic whether they had autonomic neuropathy or not. Cisapride decreased GET1/2 significantly in cirrhotic patients (Child B-C cirrhotic). Clearly, patients with autonomic neuropathy in Child B-C cirrhosis had significantly reduced GET1/2 after cisapride administration. Even though cisapride decreased GET1/2 in patients with Child B-C cirrhosis without autonomic neuropathy, this was not significant. CONCLUSION Autonomic neuropathy in advanced cirrhosis from viral hepatitis may cause prolonged gastric emptying. Cisapride can shorten gastric emptying time in such patients.

Neuromuscular diseases and disorders of the alimentary system

This review outlines the relationship and interaction between neuromuscular diseases and disorders of the alimentary system. Neuromuscular manifestations of gastrointestinal and hepatobiliary diseases are first considered. Such diseases may cause neuromuscular disorders by leading to nutritional deficiency or by more direct mechanisms. The pathogenesis, clinical features, and treatment of these various neuromuscular manifestations are discussed. The impact of disorders of nerve, neuromuscular transmission, and muscle on the alimentary system is then reviewed. The main sequelae are impaired deglutition and gastrointestinal dysmotility. The management of these complications is considered.

Cardiovascular effects of canrenone in patients with preascitic cirrhosis

In patients with cirrhosis and portal hypertension, standing induces a reduction in cardiac index (CI) and an increase in systemic vascular resistance index. Our previous studies indicate that this abnormal hemodynamic response to standing is due to an altered myocardial function, because cirrhotic patients are unable to compensate for the reduced preload with an increase in left ventricular (LV) ejection fraction (EF) and stroke volume. To evaluate whether the cardiac dysfunction in cirrhosis is influenced by canrenone, an aldosterone antagonist, 8 patients with preascitic, nonalcoholic cirrhosis, and portal hypertension underwent echocardiographic assessment of LV function and systemic hemodynamics and determinations of plasma volume, urinary sodium excretion, and plasma renin activity (PRA), aldosterone (PAC), and norepinephrine (PNE) when on a 150-mmol/d-sodium diet (baseline), after 1 month on canrenone (100 mg/d) plus a 40-mmol/d-sodium diet and after 1 month on canrenone plus a 150-mmol/d-sodium diet. Echocardiographic evaluation was performed with the patient in the supine position and during active standing. At baseline, patients had high plasma volume and normal renal function, PRA, PAC, and PNE. CI, LVEF, and stroke volume index were also normal. Standing caused a significant reduction in CI and LVEF. After canrenone and either sodium diet, CI significantly decreased, and PRA and PNE increased in the supine position. On standing, LVEF and CI did not decrease further. Plasma volume significantly decreased only after low-sodium diet plus canrenone. In conclusion, canrenone normalizes the cardiac response to the postural challenge in patients with preascitic cirrhosis.

Prevalence of autonomic dysfunction in cirrhotic and noncirrhotic portal hypertension

OBJECTIVE

Autonomic dysfunction is common in patients with cirrhosis of the liver, but more so in patients with decompensated state, and is associated with increased mortality. We evaluated the presence and extent of autonomic dysfunction in patients with extrahepatic portal venous obstruction (EHPVO) and noncirrhotic portal fibrosis (NCPF), diseases with relatively preserved liver functions.

METHODS

Heart rate variability in response to standing, deep breathing, and Valsalva maneuver and blood pressure response to sustained handgrip and standing were studied in 18 patients with EHPVO (13 mol/L, 5 F, mean age 15.2 +/- 6 yr), 12 patients with NCPF (5 mol/L, 7 F, mean age 26.4 +/- 8 yr), 15 patients with cirrhosis (7 mol/L, 8 F, mean age 12.6 +/- 6 yr), and 17 healthy controls (11 mol/L, 6 F, mean age 18.6 +/- 3 yr). Time-domain parameters of heart rate variability on 24-h ambulatory monitoring were assessed in all the patients.

RESULTS

Autonomic dysfunction was observed in 67% of EHPVO, 25% of NCPF, and 80% of cirrhotic subjects but none of the healthy controls (p < 0.05). Four of five time-domain heart rate variability indices showed significant abnormalities in patients with EHPVO (p < 0.05) and cirrhosis (p < 0.05), when compared with patients with NCPF and healthy controls.

CONCLUSIONS

Autonomic dysfunction is frequently encountered in patients with EHPVO and cirrhosis, and the presence of autonomic dysfunction in patients with noncirrhotic portal hypertension suggests a primary role of portal hypertension per se in the dysfunction.

Prolonged QTc interval and its relationship to autonomic cardiovascular reflexes in patients with cirrhosis

BACKGROUND/AIMS

We have previously shown that an abnormality in cardiac autonomic reflexes (AN) is an independent predictor of mortality in patients with chronic liver disease. Aim of this study was to determine whether there was an association between prolonged QTc interval and cardiac AN.

METHODS

Cardiac AN and QTc interval were determined in 130 patients (Child A 42, B 53, C 35) with alcoholic and non-alcoholic liver disease.

RESULTS

Prolonged QTc (>440ms) was seen in 58 (Child A 30%, B 46%, C 60%, P=0.04) patients. Autonomic tests were normal in 21%, borderline abnormal in 36% and definitely abnormal in 43%. QTc correlated with albumin (P<0.001), prothrombin time (P=0.003) and Child-Pugh score (P<0.001), but not with Valsalva ratio, heart rate variation with 6 breath/min breathing, tilt table or isometric exercise. By logistic regression analysis, QTc correlated only with Child-Pugh score (P<0.001). Mean QTc of 34 who died during the follow up was higher than survivors. Cox regression analysis showed that only Child-Pugh score and AN were independent predictors of mortality.

CONCLUSIONS

Prolonged QTc seen in liver disease is independent of their cardiac autonomic function, but is related to the severity of the liver disease.

The hyperdynamic circulation in cirrhosis: an overview

The hyperdynamic circulation begins in the portal venous bed as a consequence of portal hypertension due to the increased resistance to flow from altered hepatic vascular morphology of chronic liver disease. Dilatation of the portal vein is associated with increased blood flow, as well as the opening up or formation of veno-venous shunts and splenomegaly. At the same time, portal hypertension leads to subclinical sodium retention resulting in expansion of all body fluid compartments, including the systemic and central blood volumes. This blood volume expansion is associated with vasorelaxation, as manifested by suppression of the renin--angiotensin--aldosterone system, initially only when the patient is in the supine position. Acute volume depletion in such patients results in normalisation of the hyperdynamic circulation, whilst acute volume expansion results in exaggerated natriuresis. As liver disease progresses and liver function deteriorates, the systemic hyperdynamic circulation becomes more manifest with activation of the renin--angiotensin--aldosterone system. The presence of vasodilatation in the presence of highly elevated levels of circulating vasoconstrictors may be explained by vascular hyporesponsiveness due to increased levels of vasodilators such as nitric oxide, as well as the development of an autonomic neuropathy. However, vasodilatation is not generalised, but confined to certain vascular beds, such as the splanchnic and pulmonary beds. Even here, the status may change with the natural history of the disease, since even portal blood flow may decrease and become reversed with advanced disease. The failure of these changes to reverse following liver transplantation may be due to remodelling and angiogenesis.

Fat replacement of the glycogen in the liver as a cause of death: seventy-five years later

Seventy-five years ago, E. R. LeCount and H. A. Singer published a report in the first issue of the Archives of Pathology & Laboratory Medicine entitled "Fat Replacement of the Glycogen in the Liver as a Cause of Death." The report described 11 patients with chronic alcoholism who died suddenly. Markedly enlarged fatty livers were the only abnormality noted at postmortem examination in each of the subjects. Groups in this country and abroad subsequently repeated the authors' observation. The mechanism of sudden death in patients with fatty livers due to chronic alcoholism is currently understood to be an abnormality in the conduction system of the heart, manifested as a prolonged QT interval. The triggering event leading to the conduction defect has been suggested to be hypoglycemia complicated by hypopotassemia and hypomagnesemia. In this review we will summarize the changes that have taken place in this field since the initial publication by LeCount and Singer.

Autonomic dysfunction and hyperdynamic circulation in cirrhosis with ascites

Patients with advanced cirrhosis frequently show hemodynamic abnormalities. Autonomic dysfunction (AD) is also common and, owing to the importance of autonomic function in cardiovascular homeostasis, it may be involved in the pathogenesis of the hyperdynamic circulation. We, therefore, evaluated the hemodynamic status and autonomic function in 30 patients with cirrhosis, most of them with an advanced stage of the disease. Autonomic function was assessed with 7 cardiovascular tests exploring the vagal or sympathetic function. Each test was scored from 1 to 3 (normal, borderline, altered). Cardiac index (CI) was measured by an echocardiogram. Twenty-four (80%) patients showed an AD, this being definite in 14 (47%) patients. A vagal dysfunction (VD) was found in 19 patients (63%), this being definite in 11 patients (37%), and a sympathetic dysfunction (SD) in 7 patients (definite in 3 [10%] patients). The patients with AD showed a faster heart rate (P =.021), lower indicized peripheral vascular resistance (P =.013), and increased CI (P =.004) than patients without AD whereas mean arterial pressure did not differ. Similar results were seen by grouping patients according to the VD. AD score was directly correlated with heart rate (r = 0.53; P =.002) and CI (r = 0.45; P =. 016), and inversely correlated with peripheral vascular resistance (r = 0.46; P =.013). Even closer correlations were found with vagal score. AD (mainly VD) may be involved in the pathogenesis of the hyperdynamic circulatory syndrome of patients with advanced cirrhosis.

Autonomic and peripheral (sensorimotor) neuropathy in chronic liver disease: a clinical and electrophysiologic study

Peripheral neuropathy has been reported in association with chronic liver disease. However, the precise incidence, severity and characteristics of neuropathy, and the relationship of neuropathy to different etiologies of liver disease have not been defined. In this study, 58 patients with advanced liver disease were evaluated in detail for the presence of neuropathy. Peripheral (sensorimotor) neuropathy was found in 71% and autonomic neuropathy was found in 48% of the patients. Although the majority of patients were asymptomatic, neurological examination showed distal sensory loss to pain, or vibration or distal loss of reflexes in 17 patients (29%). Sensory neuropathy was seen more commonly than motor axonal polyneuropathy on nerve conduction studies. Quantitative sensory testing was frequently abnormal (62%) and cooling thresholds were more affected than vibration thresholds. Overall, the pattern of neuropathy in patients with liver disease conformed to the pattern expected in "dying back" or length-dependent neuropathy. The neuropathy was most severe in patients with advanced hepatic decompensation. Comparison of causes of liver disease showed no significant differences in the severity of neuropathy among the different etiologies. In conclusion, axonal sensory-motor polyneuropathy and autonomic neuropathy are commonly seen in patients with end-stage liver disease of different causes.

Noninvasive assessment of spontaneous baroreflex sensitivity in patients with liver cirrhosis

AIMS/BACKGROUND

An impairment of baroreceptor sensitivity has been found in liver cirrhosis. Noninvasive and spontaneous estimates of baroreflex sensitivity are obtained from beat-to-beat blood pressure and heart rate recordings by means of cross-spectrum analysis and calculation of alpha-index (as a measure of baroreflex gain). The aim of the present study was to investigate the function of the spontaneous baroreflex sensitivity related to clinical Child score in liver cirrhosis.

METHODS

The alpha-index was evaluated in 40 cirrhotic patients (18 with and 22 without ascites) and 17 healthy subjects by analysing finger arterial pressure recorded noninvasively with the Portapres device.

RESULTS

Baroreflex sensitivity was significantly lower in cirrhotic patients with and without ascites compared with healthy subjects (p<0.01). Furthermore, in patients with ascites the baroreflex gain was significantly related to plasma sodium (p<0.01). A significant inverse relationship was present between baroreflex gain and grade of Child score and the severity of ascites (p<0.01). There were no significant relationships between hormonal parameters (catecholamines, renin, aldosterone, arginine-vasopressin, atrial natriuretic peptide and nitric oxide) and baroreflex gain. No significant differences were found between healthy subjects and cirrhotic patients with respect to systolic and diastolic blood pressure total variability in a supine position, whilst it was lower in cirrhotic patients with ascites in a tilted position (p<0.05).

CONCLUSION

Our findings showed that baroreflex sensitivity was significantly impaired in cirrhotic patients when compared with healthy subjects. In addition, there was a significant trend toward lower baroreflex sensitivity values with the grade score of Child class (p<0.01). Spectral analysis of the alpha-index provides viable alternatives to the pharmacological approach for estimation of baroreflex sensitivity and may represent a prognostic tool to identify cirrhotic patients at increased risk of adverse events.

Autonomic involvement in Wilson's disease: a study of sympathetic skin response and RR interval variation

Autonomic nervous system involvement in Wilson's disease (WD) was studied in 25 patients by sympathetic skin response (SSR) and RR interval variation (RRIV). The control group consisted of age-matched healthy subjects. Palmar SSRs were obtained by central activation from median nerve stimulation and by activation of sympathetic trunk from magnetic stimulation of the neck. Electric SSRs were prolonged in 11 patients and absent in 2; magnetic SSRs were delayed in 4 and absent in 1; and the sympathetic central conduction time was prolonged in 3. The mean latencies and mean central conduction of the SSRs were all significantly prolonged in WD when compared to the control group. On the other hand, parasympathetic function was abnormal in 3 patients only during forced deep breathing, and as a group only mean D% was significantly reduced. The present findings suggest that autonomic dysfunction may occur in WD, and that sympathetic function is predominantly affected, mainly due to central involvement.