Regional cerebral blood flow changes in patients with cirrhosis assessed with 99mTc-HM-PAO single-photon emission computed tomography: effect of liver transplantation

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.

Regional cerebral blood flow in dogs with congenital extrahepatic portosystemic shunts before surgery and six months after successful closure

Previous studies both in humans and dogs with chronic liver diseases have shown that regional cerebral brain flow (rCBF) is altered. The current study aimed to assess abnormalities in rCBF in dogs with congenital extrahepatic portosystemic shunts (cEHPSS), both at diagnosis and after successful surgical attenuation. Furthermore, the influence of age at diagnosis, severity of hepatic encephalopathy (HE) and type of cEHPSS on rCBF were explored as a base for future research. Single photon emission computed tomography (SPECT) with 99mtechnetium-hexamethylpropylene amine oxime tracer was performed before surgical attenuation and six months postoperatively. Twenty-four dogs with cEHPSS had SPECT at time of diagnosis and 13 dogs with a confirmed closed cEHPSS had a second SPECT six months postoperatively. At diagnosis, dogs with cEHPSS had an altered rCBF distribution compared to healthy dogs. This altered rCBF distribution seemed to be most apparent in dogs ≥ one year and in dogs with overt HE at diagnosis. Six months postoperatively, only the rCBF distribution in the subcortical region decreased compared to pre-operatively. In conclusion, all dogs with cEHPSS had altered rCBF which did not seem to normalize completely six months after successful surgical attenuation. Dogs diagnosed at an older age seemed to have more distinct abnormalities in rCBF compared to younger dogs.

Neuropsychiatric performance and treatment of hepatitis C with direct-acting antivirals: a prospective study

BACKGROUND

Since direct-acting antivirals (DAAs) have been approved for the treatment of hepatitis C virus (HCV) infection, a small series of patients with new-onset neuropsychiatric alterations have been referred to us. We therefore set out to study neuropsychiatric function in relation to DAAs prospectively.

METHODS

Ten patients with cirrhosis and 12 post-liver transplant (post-LT) patients were enrolled. All underwent wake electroencephalography (EEG) and a neuropsychological evaluation (paper and pencil battery, simple/choice reaction times, working memory task) at baseline, at the end of treatment with DAAs and after 6 months. At the same time points, full blood count, liver/kidney function tests, quantitative HCV RNA, ammonia and immunosuppressant drug levels were obtained, as appropriate.

RESULTS

Patients with cirrhosis were significantly older than post-LT patients (65±12 vs 55±7 years; P<0.05). Neuropsychological performance and wake EEG were comparable in the two groups at baseline. At the end of a course of treatment with DAAs, a significant slowing in choice reaction times and in the EEG (increased relative delta power) was observed in patients with cirrhosis, which resolved after 6 months. In contrast, no significant changes over time were observed in the neuropsychiatric performance of post-LT patients. No significant associations were observed between neuropsychiatric performance and stand-alone/combined laboratory variables.

CONCLUSION

Some degree of neuropsychiatric impairment was observed in relation to treatment with DAAs in patients with cirrhosis, but not in post-LT patients, suggesting that the former may be sensitive to mild DAA neurotoxicity.

The risk of coronary artery disease and cerebrovascular disease in patients with hepatitis C: A systematic review and meta-analysis

BACKGROUND/OBJECTIVES

Some studies suggest that patients with hepatitis C virus (HCV) infection have an increased risk of coronary artery disease (CAD) and cerebrovascular disease. Unfortunately, available data on this association are widely variable. We have performed a systematic review and meta-analysis of literature to evaluate the risk of cardio-cerebrovascular disease (CCD) associated with HCV.

METHODS

Studies reporting on CCD risk associated with HCV were systematically searched in the PubMed, Web of Science, Scopus and EMBASE databases.

RESULTS

Twenty-seven studies (34 data-sets) showed a significantly increased CCD risk in 297,613 HCV patients as compared with 557,814 uninfected controls (OR: 1.428; 95% CI: 1.214, 1.681). These results were confirmed when separately considering the risk of CAD (20 studies, OR: 1.382; 95% CI: 1.103, 1.732) and of cerebrovascular disease (13 studies, OR: 1.485; 95% CI: 1.079, 2.044). Similar results were confirmed when analyzing 21 studies reporting adjusted risk estimates (OR: 1.448; 95% CI: 1.218, 1.722) and when, after excluding studies defining CAD as positive angiographic or electrocardiographic evidence, we specifically included the 17 studies reporting on acute CCD-related events (OR: 1.357; 95% CI: 1.103, 1.670). Moreover, 4 studies evaluating CCD-related deaths showed a higher risk in HCV patients than controls (OR: 1.772; 95% CI: 1.448, 2.168; P<0.0001). Meta-regression models suggested a direct association between prevalence of cirrhosis and difference in CCD risk between HCV patients and controls.

CONCLUSIONS

Results of our large meta-analysis suggest that HCV-infected subjects experience an increased risk of CCD. This should be considered to plan specific cardiovascular prevention strategies in this clinical setting.

Cirrhotic Multiorgan Syndrome

Patients with cirrhosis and portal hypertension are at an increased risk of the development of circulatory dysfunction that may potentially result in multiple organ failure. Apart from the liver, this may involve the heart, lungs, kidneys, the immune system, the adrenal glands, and other organ systems. As the disease progresses, the circulation becomes hyperdynamic, and signs of cardiac, pulmonary, and renal dysfunction are observed, in addition to reduced survival. Infections and an altered cardiac function known as cirrhotic cardiomyopathy may be precipitators for the development of other complications such as hepatorenal syndrome. In patients with chronic organ dysfunction, various precipitating events may induce an acute-on-chronic renal failure and acute-on-chronic liver failure that negatively affect the prognosis. Future research on the pathophysiologic mechanisms of the complications and the precipitating factors is essential to understand the basics of the treatment of these challenging conditions. The aim of the present review is to focus on the development and precipitating factors of various organ failures in patients with decompensated cirrhosis.

Default mode network functional connectivity: a promising biomarker for diagnosing minimal hepatic encephalopathy: CONSORT-compliant article

To investigate the contribution of brain default mode network (DMN) in the early diagnosis of the minimal hepatic encephalopathy (MHE), the mildest form of HE from cirrhotic patients by using resting-state functional magnetic resonance imaging (rs-fMRI). This study was approved by the local ethical committee, and a written informed consent was obtained from each participant. A total of 103 cirrhotic patients (34 MHE, 69 non-HE) and 103 matched healthy controls underwent rs-fMRI scanning. The DMN correlation map was acquired by using unbiased seed-based functional connectivity analysis and compared among MHE patients, non-HE patients, and healthy controls with analysis of variance tests. Pearson correlation analysis was performed between the abnormal DMN connectivity and neuropsychological performances. Receiver operator characteristic (ROC) analysis was used to evaluate the contribution of DMN connectivity strength in the differential diagnosis between MHE and non-HE. Compared with the healthy controls, MHE and non-HE patients showed decreased DMN connectivity in medial prefrontal cortex (MPFC), left superior frontal gyrus (SFG), left temporal lobe, and bilateral middle temporal gyri (MTG). The MHE patients showed even more decreased connectivity in MPFC, left SFG, and right MTG when compared with non-HE patients. Pearson correlation analyses revealed that the decreased connectivity strength of some DMN regions correlated with patients' neuropsychological tests scores. Connectivity strength of the MPFC, right MTG, and left SFG could differentiate MHE from non-HE, of which the MPFC had the highest effectiveness (sensitivity = 81.5%, specificity = 70.4%). Cirrhotic patients had gradually reduced DMN functional connectivity from non-HE patients to MHE patients. DMN function, especially the MPFC, might be a useful imaging marker for differentiating MHE from cirrhotic patients.

Abnormal functional connectivity within the default mode network in patients with HBV-related cirrhosis without hepatic encephalopathy revealed by resting-state functional MRI

By means of "task free" resting-state functional magnetic resonance imaging (rs-fMRI), abnormal functional connectivity (FC) of the default mode network (DMN) in cirrhotic patients with hepatic encephalopathy (HE) has been reported; however, little is known about the changes of DMN in cirrhotic patients without overt or minimal HE. The aim of this study was to investigate whether there was a disruption of the FC within the DMN in patients with hepatitis B virus (HBV)-related cirrhosis without any signs of HE. Fifty one patients with HBV-related cirrhosis without HE and 61 age- and gender-matched healthy controls underwent the rs-fMRI. Seed-based region-to-region FC was used to analyze the connectivity between each pair of regions within the DMN, including posterior cingulate cortex (PCC), medial prefrontal cortex (mPFC), hippocampal formation (HF), inferior parietal cortex (IPC), and medial temporal lobe (MTL). Pearson correlation analysis was performed between the abnormal FC strength within the DMN and venous blood ammonia levels in patients. Compared with the controls, patients with HBV-related cirrhosis without HE demonstrated significantly decreased region-to-region FC between the mPFC and bilateral MTL, right HF, and left IPC, as well as between the right MTL and left IPC, right HF, and PCC. A significant negative relationship was observed between blood ammonia levels and connectivity strength between the mPFC and left IPC in patients. These results suggest that patients with HBV-related cirrhosis without HE had disrupted functional connectivty within the DMN, even before the appearance of minimal HE.

Splanchnic vasodilation and hyperdynamic circulatory syndrome in cirrhosis

Portal hypertension is a clinical syndrome which leads to several clinical complications, such as the formation and rupture of esophageal and/or gastric varices, ascites, hepatic encephalopathy and hepato-renal syndrome. In cirrhosis, the primary cause of the increase in portal pressure is the enhanced resistance to portal outflow. However, also an increase in splanchnic blood flow worsens and maintains portal hypertension. The vasodilatation of arterial splanchnic vessels and the opening of collateral circulation are the determinants of the increased splanchnic blood flow. Several vasoactive systems/substances, such as nitric oxide, cyclooxygenase-derivatives, carbon monoxide and endogenous cannabinoids are activated in portal hypertension and are responsible for the marked splanchnic vasodilatation. Moreover, an impaired reactivity to vasoconstrictor systems, such as the sympathetic nervous system, vasopressin, angiotensin II and endothelin-1, plays a role in this process. The opening of collateral circulation occurs through the reperfusion and dilatation of preexisting vessels, but also through the generation of new vessels. Splanchnic vasodilatation leads to the onset of the hyperdynamic circulatory syndrome, a syndrome which occurs in patients with portal hypertension and is characterized by increased cardiac output and heart rate, and decreased systemic vascular resistance with low arterial blood pressure. Understanding the pathophysiology of splanchnic vasodilatation and hyperdynamic circulatory syndrome is mandatory for the prevention and treatment of portal hypertension and its severe complications.

Brain edema in acute liver failure and chronic liver disease: similarities and differences

Hepatic encephalopathy (HE) is a complex neuropsychiatric syndrome that typically develops as a result of acute liver failure or chronic liver disease. Brain edema is a common feature associated with HE. In acute liver failure, brain edema contributes to an increase in intracranial pressure, which can fatally lead to brain stem herniation. In chronic liver disease, intracranial hypertension is rarely observed, even though brain edema may be present. This discrepancy in the development of intracranial hypertension in acute liver failure versus chronic liver disease suggests that brain edema plays a different role in relation to the onset of HE. Furthermore, the pathophysiological mechanisms involved in the development of brain edema in acute liver failure and chronic liver disease are dissimilar. This review explores the types of brain edema, the cells, and pathogenic factors involved in its development, while emphasizing the differences in acute liver failure versus chronic liver disease. The implications of brain edema developing as a neuropathological consequence of HE, or as a cause of HE, are also discussed.

Dynamic susceptibility contrast-enhanced first-pass perfusion MR imaging in patients with subclinical hepatic encephalopathy

BACKGROUND AND PURPOSE

Subclinical hepatic encephalopathy (SHE) is frequently reported on single-photon emission computed tomography (SPECT), but is rarely described with magnetic resonance (MR) techniques. This study aimed to investigate hemodynamic changes in brain basal ganglia in patients with SHE using dynamic susceptibility contrast (DSC)-enhanced MR perfusion imaging.

METHODS

Twelve patients with SHE and ten age- and education-matched volunteers agreed to undergo MR examination. The scanning protocol included conventional anatomical images and DSC-enhanced perfusion MR imaging. Using MGH perfusion software, parameter maps of cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) were created. The bilateral caudate nucleus head, globus pallidus, putamen and thalamus were selected as regions of interest (ROI), with ipsilateral white matter of the frontal lobe used as reference. Ratios (ROI versus ipsilateral white matter in frontal lobe) for CBF, CBV and MTT in the patient group were compared with those in the control group.

RESULTS

The CBF ratios for every ROI were higher in SHE patients versus the controls. Statistically, significant increases were detected in the left globus pallidus, putamen and thalamus (P<0.05). For MTT, the reduction in values reached statistical significance in the right head of the caudate nucleus and bilateral thalamus (P<0.05). CBV values were not significantly different compared with those of the control group (P>0.05).

CONCLUSION

Increased CBF and decreased MTT values in the basal ganglia and thalamus were identified in patients with SHE. The CBF increase was compatible with the idea that the CBF is redistributed from cortical areas to the basal ganglia structures.

Liver transplantation for patients with alcoholic liver disease: an open question

End-stage alcoholic liver disease is a recognised indication for liver transplantation but some questions on the matter remain open. It is difficult to quantify alcohol consumption, and a single definition of post-transplant relapse is lacking. Moreover, there are no internationally accepted criteria for the selection of candidates for liver transplantation and the eligibility parameters for these patients are controversial. Additional clinical and psychological evaluations are necessary in this setting, especially to establish the risk of alcohol relapse. Nevertheless, patient and graft survival rates after liver transplantation in alcoholic liver disease are comparable to those after transplant for other aetiologies, alcohol consumption relapse being one of the most important problems in the post-transplant phase. In conclusion, alcohol-related liver disease is a good indication for liver transplantation. The main future goals are to formulate a well-defined pre-transplant approach and a single definition of alcohol relapse and to improve prevention strategies.

Neurologic complications after solid organ transplantation

Neurologic complications are common after solid organ transplantation and are associated with significant morbidity. Approximately one-third of transplant recipients experiences neurologic alterations with incidence ranging from 10% to 59%. The complications can be divided into such of those common to all types of transplant and others of those specific to transplanted organ. The most common complication seen with all types of transplanted organ is neurotoxicity attributable to immunosuppressive drugs, followed by seizures, opportunistic central nervous system (CNS) infections, cardiovascular events, encephalopathy and de novo CNS neoplasms. Amongst immunosuppressants, calcineurin inhibitors are the main drugs involved in neurotoxicity, leading to complications which ranges from mild symptoms, such as tremors and paresthesia to severe symptoms, such as disabling pain syndrome and leukoencephalopathy. Neurologic complications of liver transplantation are more common than that of other solid organ transplants (13-47%); encephalopathy is the most common CNS complication, followed by seizures; however, central pontine myelinolysis can appear in 1-8% of the patients leading to permanent disabilities or death. In kidney transplanted patients, stroke is the most common neurologic complication, whereas cerebral infarction and bleeding are more typical after heart transplantation. Metabolic, electrolyte and infectious anomalies represent common risk factors; however, identification of specific causes and early diagnosis are still difficult, because of patient's poor clinical status and concomitant systemic and metabolic disorders, which may obscure symptoms.

Vasoactive factors and hemodynamic mechanisms in the pathophysiology of portal hypertension in cirrhosis

Portal hypertension is primarily caused by the increase in resistance to portal outflow and secondly by an increase in splanchnic blood flow, which worsens and maintains the increased portal pressure. Increased portal inflow plays a role in the hyperdynamic circulatory syndrome, a characteristic feature of portal hypertensive patients. Almost all the known vasoactive systems/substances are activated in portal hypertension, but most authors stress the pathogenetic role of endothelial factors, such as COX-derivatives, nitric oxide, carbon monoxide. Endothelial dysfunction is differentially involved in different vascular beds and consists in alteration in response both to vasodilators and to vasoconstrictors. Understanding the pathogenesis of portal hypertension could be of great utility in preventing and curing the complications of portal hypertension, such as esophageal varices, hepatic encephalopathy, ascites.

Quantitative EEG analysis before and after liver transplantation

Quantitative EEG has been shown to be effective for the assessment of hepatic encephalopathy. Initial quantitative EEG studies of patients who had undergone liver transplantation demonstrated improvement of frequency and the alpha-theta power ratio in the occipital area. This study involved the assessment of comprehensive quantitative EEG variables over the entire cortex following transplantation. Fourteen subjects underwent EEG recording prior to transplantation. Eight (6 without complications and 2 having problems with rejection) underwent the same recording between 3 and 6 months following transplantation. For all subjects, EEG variables showing significant changes from pre- to post-transplantation included posterior alpha frequency (increase, p < or = .03), central theta absolute power (decrease, p < or = .03), theta relative power over anterior, central, and posterior regions (decrease, p < or = .02, p < or = .01, p < or = .03, respectively), posterior beta absolute power (increase, p < or = .01), and central and posterior beta relative power (increase, p < or = .04, p < or = .04, respectively). When the two subjects with complications were removed from the analyses, these variables and also anterior alpha absolute power (increase, p < or = .02), alpha relative power over anterior, central, and posterior regions (increase, p < or = .05, p < or = .03, p < or = .04, respectively), and anterior and central theta absolute power (decrease, p < or = .05, p < or = .04, respectively) showed significant pre- to post-transplant changes. In conclusion, a combination of quantitative EEG parameters which are most affected by liver transplantation might provide an effective assessment tool for determining and quantitatively monitoring the cerebral status of post-transplant patients.

Improvement of regional cerebral blood flow after oral intake of branched-chain amino acids in patients with cirrhosis

AIM: To evaluate the effect of oral intake of branched-chain amino acids (BCAA) on brain perfusion in patients with liver cirrhosis.

METHODS: Single photon emission computed tomography scans were performed in 43 patients with cirrhosis and in 15 age-matched healthy subjects. Twenty-nine out of forty-three patients were randomly treated with either BCAA granules or placebo, and single photon emission computed tomography was performed before and after the treatment. We measured the regional cerebral blood flow values using a three-dimensional stereotaxic region of interest template.

RESULTS: Cirrhotic patients had regions of significant hypoperfusion in the bilateral central (right P = 0.039, P<0.05; left P = 0.006 P<0.01), parietal (right P = 0.018, P<0.05; left P = 0.009, P<0.01), angular (right P = 0.039, P<0.05; left P = 0.008, P<0.01), and left pericallosal segments (P = 0.038 P<0.05) as compared with healthy subjects. A significant increase in cerebral perfusion was observed 70 min after the oral intake of BCAA in the angular (right P = 0.012, P<0.05; left P = 0.049, P<0.05), temporal (right P = 0.012, P<0.05; left P=0.038, P<0.05), pericallosal segments (right P = 0.025, P<0.05; left P = 0.049, P<0.05) and left precentral (P = 0.044, P<0.05), parietal (P = 0.040, P<0.05) and thalamus (P = 0.033, P<0.05). No significant change in perfusion was observed in the placebo group.

CONCLUSION: Administration of BCAA rapidly improves cerebral perfusion.

Liver transplantation in alcoholic patients

Alcoholic liver disease is one of the most common causes of cirrhosis and indications for orthotopic liver transplantation in Europe and North America. The reluctance to transplant alcoholics stems in part from the view that alcoholics bear responsibility for their illness. There is also the perception that the alcoholic person is likely to relapse into alcohol use after transplantation and thereby damage the allograft. In this review, we considered the evaluation for and outcome of liver transplantation in alcoholics with special attention to the specific risks of alcohol relapse, to show that alcoholism should be considered like other co-morbid states rather than as a moral flaw.

Evaluation of cingulate gyrus blood flow in patients with liver cirrhosis

Although neuropsychological tests are commonly applied to detect minimal hepatic encephalopathy (HE) in patients with liver cirrhosis (LC), they provide no information about the cerebral regions involved. Recently, it has been reported that some populations of alcoholic cirrhotics, with mild HE, have reduced cerebral metabolic rate for glucose in bifrontal cortices and in the anterior cingulate gyrus. We evaluated the degree of reduction in blood flow at the anterior cingulate gyrus and the frontal lobes in cirrhotic patients who underwent single photon emission computed tomography (SPECT). Data were obtained from 47 cirrhotic patients and 47 subjects without LC. Three radiologists unaware of the results of laboratory tests visually evaluated the transaxial, coronal, and sagittal views of SPECT. The area and the degree of blood flow reduction in the anterior cingulate gyrus and frontal lobes were scored. Reduced blood flow in the anterior cingulate gyrus was observed in most LC patients. In patients without overt HE, poor performance in neuropsychological tests was correlated with reduced cerebral blood flow in the anterior cingulate gyrus. Blood flow in the anterior cingulate gyrus as measured by SPECT may be a simple and good indicator of cerebral functional changes in patients with LC.

Characteristics of minimal hepatic encephalopathy

The term minimal hepatic encephalopathy refers to the subtle changes in cognitive function, electrophysiological parameters, cerebral neurochemical/neurotransmitter homeostasis, cerebral blood flow, metabolism, and fluid homeostasis that can be observed in patients with cirrhosis who have no clinical evidence of hepatic encephalopathy. Use of this term emphasizes the fact that the entity of hepatic encephalopathy is a single syndrome with quantitatively distinct features relating to severity. The absence of clinical evidence of hepatic encephalopathy is key to the diagnosis and can only be determined by a detailed assessment of the patients' history and a comprehensive neurological assessment of consciousness, cognitive, and motor function. The neuropsychological features of minimal hepatic encephalopathy point to a disorder of executive functioning, particularly selective attention and psychomotor speed, but other abnormalities may be observed. Alterations in electrophysiological variables have been described; endogenous evoked potentials are, in principle, more likely to reflect the presence of minimal hepatic encephalopathy, since they reflect cognitive phenomena rather than mere stimulus conduction but the specificity of the changes observed is unclear at present. Changes have also been described in the execution of diadochokinetic movements and in the capacity to discriminate flickering light, both of which may have diagnostic potential. The changes observed in cerebral blood flow and metabolism in SPET, PET, and 1H and 31P MRS studies reflect the pathogenic process that underlies the condition rather than providing diagnostic information. Similarly, the morphological brain abnormalities identified in this population, including mild brain oedema, hyperintensity of the globus pallidus and other subcortical nuclei observed in cerebral MR studies, and the central and cortical atrophy observed in neural imaging studies, are unlikely to have diagnostic utility. The presence of minimal hepatic encephalopathy is not without clinical consequence; it has a detrimental effect on health-related quality of life, the ability to perform complex tasks such as driving, and on outcome.

Does liver-disease aetiology have a role in cerebral blood-flow alterations in liver cirrhosis?

BACKGROUND

Studies using brain-imaging techniques have shown changes in regional blood flow (rCBF) in patients with liver cirrhosis. It remains unknown whether the aetiology of liver disease accounts for these changes.

AIMS

To evaluate whether the aetiology of liver cirrhosis is associated with different patterns of rCBF.

MATERIALS AND METHODS

A total of 50 patients with end-stage liver disease and no overt encephalopathy were studied. Thirteen age-matched subjects admitted to the neurology department for headache were used as controls. Exclusion criteria were focal brain lesions, severe brain atrophy and any abnormalities found on computed tomography scan suggesting other central nervous system diseases, alcohol intake or use of neuroactive drugs for at least 6 months. rCBF was assessed using single-positron-emission tomography (SPECT) with 99mTc-hexamethylpropylene amine oxime (99mTc-HM-PAO) as a tracer in all patients and controls. The Mann-Whitney U test was used for statistical analysis.

RESULTS

The liver-disease aetiology was as follows: alcoholic (A) in 19 patients; viral (V) (hepatitis B virus, hepatitis D virus, hepatitis C virus) in 14 patients; alcoholic with concomitant viral (A + V) in five patients; and cholestatic (C) (primary biliary cirrhosis, primary sclerosing cholangitis) in 12 patients. SPECT showed significantly lower rCBF in cirrhotic patients than in controls for most cortical and subcortical regions and in alcoholic and viral patients than in cholestatic liver disease patients for some cortical regions. When patients were grouped according to previous alcohol abuse (including cases with a concomitant viral aetiology), rCBF was significantly lower in the frontal superior, medial and temporal inferior regions in the alcoholic group.

CONCLUSIONS

Cerebral blood flow is significantly lower in patients with liver cirrhosis than in controls and, among cirrhotics, it is lower in alcoholic and viral cirrhosis than in cholestatic liver disease. In patients with previous alcohol abuse, cerebral blood flow was significantly more reduced in the frontal and temporal regions compared with patients without previous alcohol abuse.

Preoperative preparation of patients with advanced liver disease

OBJECTIVE

To review the characteristic features of patients with advanced liver disease that may lead to increased perioperative morbidity and mortality rates.

DESIGN

Literature review.

RESULTS

Patients with end-stage liver disease are at high risk of major complications and death following surgery. The most common complications are secondary to acute liver failure and include severe coagulopathy, encephalopathy, adult respiratory distress syndrome, acute renal failure, and sepsis. The degree of malnutrition, control of ascites, level of encephalopathy, prothrombin time, concentration of serum albumin, and concentration of serum bilirubin predict the risk of complications and death following surgery. Other determinants of adverse outcome include emergency surgery, advanced age, and cardiovascular disease. Portal hypertension is a prominent feature of advanced liver disease, and it predisposes the patient to variceal hemorrhage, hepatorenal syndrome, hepatopulmonary syndrome, and uncontrolled ascites. Portal hypertension can be ameliorated by percutaneous or surgical portasystemic shunting procedures. If well-defined contraindications are not present, patients with advanced liver disease should be evaluated for orthotopic liver transplantation from a cadaver donor or possible living-related liver transplantation.

CONCLUSIONS

Optimal preparation, which addresses the common features of advanced liver disease, may decrease the risk of complications or death following surgery. Preparation should include correcting coagulopathy, minimizing preexisting encephalopathy, preventing sepsis, and optimizing renal function.

Single photon emission computed tomography and statistical parametric mapping analysis in cirrhotic patients with and without minimal hepatic encephalopathy

OBJECTIVE

The early diagnosis and treatment of cognitive impairment in cirrhotic patients is needed to improve the patients' daily living. In this study, alterations of regional cerebral blood flow (rCBF) were evaluated in cirrhotic patients using statistical parametric mapping (SPM). The relationships between rCBF and neuropsychological test, severity of disease and biochemical data were also assessed.

METHODS

99mTc-ethyl cysteinate dimer single photon emission computed tomography was performed in 20 patients with non-alcoholic liver cirrhosis without overt hepatic encephalopathy (HE) and in 20 age-matched healthy subjects. Neuropsychological tests were performed in 16 patients; of these 7 had minimal HE. Regional CBF images were also analyzed in these groups using SPM.

RESULTS

On SPM analysis, cirrhotic patients showed regions of significant hypoperfusion in the superior and middle frontal gyri, and inferior parietal lobules compared with the control group. These areas included parts of the premotor and parietal associated areas of the cortex. Among the cirrhotic patients, those with minimal HE had regions of significant hypoperfusion in the cingulate gyri bilaterally as compared with those without minimal HE.

CONCLUSIONS

Abnormal function in the above regions may account for the relatively selective neuropsychological deficits in the cognitive status of patients with cirrhosis. These findings may be important in the identification and management of cirrhotic patients with minimal HE.

Value of regional cerebral blood flow in the evaluation of chronic liver disease and subclinical hepatic encephalopathy

AIMS

Regional changes in cerebral blood flow in patients with chronic hepatitis, cirrhosis and subclinical hepatic encephalopathy were investigated in the present study using single photon emission computed tomography (SPECT).

METHODS

Twenty patients with cirrhosis, 11 patients with chronic hepatitis, and nine healthy controls were included in the study. Cerebral SPECT were obtained for all patients. The percentages of cerebral blood flow of 14 regions to the cerebellar blood flow were determined. Only the patients with cirrhosis underwent psychometric evaluation: visual evoked potentials (VEP) measurements and electroencephalogram (EEG) recordings along with blood levels of albumin, bilirubin, and ammonia were measured and prothrombin time was determined in cirrhotic patients. These patients were classified according to the Child-Pugh classification.

RESULTS

Among cirrhotic patients, six had abnormal results in VEP studies, 11 in psychometric tests and with six in EEG evaluation. Any abnormality in psychometric tests and/or VEP studies is taken as the main criterion; subclinical hepatic encephalopathy was detected in 12 of 20 patients. According to SPECT results in patients with subclinical encephalopathy, a statistically significant decrease in cerebral blood flow in right thalamus and nearly significant decrease in left thalamus were observed. Regional blood flow was significantly higher in the frontal lobes of patients with cirrhosis when compared with healthy controls. Similarly, cerebral blood flow in frontal and cingulate regions was significantly higher in patients with chronic hepatitis than in healthy controls. There was no relationship between cerebral blood flow and blood levels of ammonia or Child-Pugh score, in cirrhotic patients.

CONCLUSION

Significant changes in cerebral blood flow may be present in chronic liver diseases and the authors suggest that the measurement of changes in cerebral blood flow might be useful in detecting subclinical hepatic encephalopathy.

Improvement of regional cerebral blood flow after treatment with branched-chain amino acid solutions in patients with cirrhosis

OBJECTIVE

The administration of solutions rich in branched-chain amino acids leads to mental recovery from acute hepatic encephalopathy in patients with liver cirrhosis. However, the mechanism of action of branched-chain amino acids remains unclear. The purpose of this study was to evaluate the effect of intravenous infusion of branched-chain amino acids on brain perfusion in patients with liver cirrhosis.

METHODS

Single photon emission computed tomography scans were performed in 14 patients with liver cirrhosis before and after the administration of branched-chain amino acids in a single-day split-dose protocol. The per cent change in regional brain perfusion was calculated in high frontal, parietal, temporal, occipital lobes and cerebellum. Thereafter, statistical parametric mapping was performed to identify brain regions with abnormal cerebral perfusion.

RESULTS

Intravenous infusion of solutions enriched with branched-chain amino acids induced a 13-20% increase in regional cerebral blood flow. Cirrhotic patients had regions of significant hypoperfusion, as determined by statistical parametric mapping, in the left superior parietal and posterior cingulate as compared to the control group. This hypoperfusion of parietal and cingulate regions was not detected after treatment with solutions of branched-chain amino acids.

CONCLUSIONS

The results of the present study suggest that administration of solutions enriched with branched-chain amino acids improves cerebral perfusion in patients with cirrhosis.

Cerebral vascular resistance assessed by transcranial color Doppler ultrasonography in patients with chronic liver diseases

BACKGROUND AND AIM

Cerebral hemodynamic derangement is well known in patients with liver cirrhosis. The advent of transcranial Doppler enables a non-invasive observation of cerebral hemodynamics. To evaluate the clinical usefulness we examined cross-sectionally and longitudinally cerebral hemodynamic parameters in patients with cirrhosis.

METHODS

The subjects of the cross-sectional study were 117 patients with cirrhosis, 15 patients with chronic hepatitis and 25 healthy controls. The longitudinal study included 26 cirrhotic patients without encephalopathy, and 27 cirrhotic patients with encephalopathy. The pulsatility and resistive indices of the right middle cerebral artery were used as parameters of cerebral hemodynamics.

RESULTS

Cerebral pulsatility and resistive indices were significantly higher in patients with cirrhosis (1.05 +/- 0.23, P < 0.0001 and 0.63 +/- 0.07, P < 0.0001, respectively) than in the controls (0.75 +/- 0.11 and 0.55 +/- 0.05, respectively) and patients with chronic hepatitis (0.81 +/- 0.11 and 0.52 +/- 0.05, respectively). Cerebral pulsatility and resistive indices were significantly related with the severity of liver cirrhosis. Patients with encephalopathy had higher cerebral pulsatility and resistive indices than patients without encephalopathy. In the longitudinal studies, cerebral pulsatility and resistive indices were changed in parallel with the severity of cirrhosis and encephalopathy. Cerebral pulsatility and resistive indices were significantly correlated with the blood ammonia level and serum levels of bilirubin and albumin.

CONCLUSION

These cross-sectional and longitudinal studies showed that cerebral vascular resistance indices measured by using transcranial Doppler were increased in association with the severity of cirrhosis and encephalopathy. Cerebral pulsatility and resistive indices are real-time and useful parameters to assess and monitor cirrhotic patients.

Regional and systemic hemodynamic disturbances in cirrhosis

In cirrhosis of the liver there is an imbalance between factors mediating vasodilatation such as nitric oxide and factors mediating vasoconstriction such as endothelins. These imbalances result in portal hypertension, hepatorenal syndrome, portopulmonary hypertension, hepatopulmonary syndrome, as well as alterations in cerebral blood flow.