Could metabolic liver function tests predict mortality on waiting list for liver transplantation? A study on 560 patients

[Indocyanine green in liver transplantation]

The purpose of this study was to evaluate the first own experience of using indocyanine green (ICG) in liver transplantation compared to literature data and to determine its potential for clinical practice. Liver transplantation is an effective option for patients with end-stage disease, but this procedure is associated with many problems such as graft rejection, graft dysfunction, surgical risk and postoperative management. Modern methods for assessing graft function have their limitations, so a more efficient method is needed. According to this review, ICG fluorescence is valuable for effective intraoperative blood flow control, assessment of graft function, intraoperative and postoperative monitoring of clinical status. ICG fluorescence can also predict clinical status of patients at all stages of liver transplantation. Routine ICG fluorescence method is advisable in liver transplantation to improve outcomes and optimize treatment process.

Validation of a new prognostic model to predict short and medium-term survival in patients with liver cirrhosis

Background

MELD score and MELD score derivates are used to objectify and grade the risk of liver-related death in patients with liver cirrhosis. We recently proposed a new predictive model that combines serum creatinine levels and maximum liver function capacity (LiMAx®), namely the CreLiMAx risk score. In this validation study we have aimed to reproduce its diagnostic accuracy in patients with end-stage liver disease.

Methods

Liver function of 113 patients with liver cirrhosis was prospectively investigated. Primary end-point of the study was liver-related death within 12 months of follow-up.

Results

Alcoholic liver disease was the main cause of liver disease (n = 51; 45%). Within 12 months of follow-up 11 patients (9.7%) underwent liver transplantation and 17 (15.1%) died (13 deaths were related to liver disease, two not). Measures of diagnostic accuracy were comparable for MELD, MELD-Na and the CreLiMAx risk score as to power in predicting short and medium-term mortality risk in the overall cohort: AUROCS for liver related risk of death were for MELD [6 months 0.89 (95% CI 0.80–0.98) p < 0.001; 12 months 0.89 (95% CI 0.81–0.96) p < 0.001]; MELD-Na [6 months 0.93 (95% CI 0.85–1.00) p < 0.001 and 12 months 0.89 (95% CI 0.80–0.98) p < 0.001]; CPS 6 months 0.91 (95% CI 0.85–0.97) p < 0.01 and 12 months 0.88 (95% CI 0.80–0.96) p < 0.001] and CreLiMAx score [6 months 0.80 (95% CI 0.67–0.96) p < 0.01 and 12 months 0.79 (95% CI 0.64–0.94) p = 0.001]. In a subgroup analysis of patients with Child-Pugh Class B cirrhosis, the CreLiMAx risk score remained the only parameter significantly differing in non-survivors and survivors. Furthermore, in these patients the proposed score had a good predictive performance.

Conclusion

The CreLiMAx risk score appears to be a competitive and valid tool for estimating not only short- but also medium-term survival of patients with end-stage liver disease. Particularly in patients with Child-Pugh Class B cirrhosis the new score showed a good ability to identify patients not at risk of death.

Could Ultrasound Elastography Reflect Liver Function?

The purpose of this study was to investigate whether ultrasound elastography reflects liver function reserve relative to liver fibrosis histology. Sixty-five New Zealand rabbits were divided into an experimental group (n = 45) and a control group (n = 20). In the experimental group, liver fibrosis (F1-F4) was induced by subcutaneous injection of carbon tetrachloride. Point shear wave elastography and the indocyanine green (ICG) elimination test were performed for the two groups at 4-wk intervals for 56 wk. The liver stiffness value (LSV) and the ICG retention rate at 15 min (ICGR15) were obtained, and the correlation between them was investigated. The median LSVs of stages F0-F4 were 3.92 kPa (1.91-8.53 kPa), 5.02 kPa (2.39-8.91 kPa), 7.87 kPa (5.21-12.26 kPa), 12.83 kPa (5.92-16.79 kPa) and 16.64 kPa (9.76-29.50 kPa), respectively. The median ICGR15 values of stages F0-F4 were 8.7% (4.8%-15.6%), 10.8% (5.6%-20.3%), 19.2% (12.3%-26.7%), 31.0% (20.9%-41.0%) and 45.6% (22.1%-60.9%). There were significant differences in LSVs and ICGR15 values among the different stages of liver fibrosis (p <0.01). A positive correlation was observed between LSV and ICGR15 (r = 0.7497, p < 0.0001). A strong correlation was observed between liver stiffness and liver function reserve, indicating ultrasound elastography may reflect liver function reserve in different degrees of liver fibrosis.

Child-Pugh Versus MELD Score for the Assessment of Prognosis in Liver Cirrhosis: A Systematic Review and Meta-Analysis of Observational Studies

Child-Pugh and MELD scores have been widely used for the assessment of prognosis in liver cirrhosis. A systematic review and meta-analysis aimed to compare the discriminative ability of Child-Pugh versus MELD score to assess the prognosis of cirrhotic patients.PubMed and EMBASE databases were searched. The statistical results were summarized from every individual study. The summary areas under receiver operating characteristic curves, sensitivities, specificities, positive and negative likelihood ratios, and diagnostic odds ratios were also calculated.Of the 1095 papers initially identified, 119 were eligible for the systematic review. Study population was heterogeneous among studies. They included 269 comparisons, of which 44 favored MELD score, 16 favored Child-Pugh score, 99 did not find any significant difference between them, and 110 did not report the statistical significance. Forty-two papers were further included in the meta-analysis. In patients with acute-on-chronic liver failure, Child-Pugh score had a higher sensitivity and a lower specificity than MELD score. In patients admitted to ICU, MELD score had a smaller negative likelihood ratio and a higher sensitivity than Child-Pugh score. In patients undergoing surgery, Child-Pugh score had a higher specificity than MELD score. In other subgroup analyses, Child-Pugh and MELD scores had statistically similar discriminative abilities or could not be compared due to the presence of significant diagnostic threshold effects.Although Child-Pugh and MELD scores had similar prognostic values in most of cases, their benefits might be heterogeneous in some specific conditions. The indications for Child-Pugh and MELD scores should be further identified.

Current use and perspective of indocyanine green clearance in liver diseases

Indocyanine green (ICG) is a water-soluble anionic compound that binds to plasma proteins after intravenous administration. It is selectively taken up at the first pass by hepatocytes and excreted unchanged into the bile. With the development of ICG elimination measurement by spectrophotometry, the ICG retention test has become a safe, rapid, reproducible, inexpensive and noninvasive tool for the assessment of liver function. Clinical evidence suggests that the ICG retention test can enable the establishment of tailored management strategies by providing prognostic information. In particular, this method has been evaluated as a prognostic marker in patients with advanced cirrhosis or awaiting liver transplantation. In addition, it is used as a marker of portal hypertension in cirrhotic patients, as a prognostic factor in intensive care units and for the assessment of liver function in patients undergoing liver surgery. Since recent technology enables ICG-PDR to be measured noninvasively at the bedside, this parameter is an attractive addition to liver function and regional haemodynamic monitoring. However, the current state-of-the-art as concerns this technology remains at a low level of evidence and thorough assessment is required.

Critical appraisal of 13C breath tests for microsomal liver function: aminopyrine revisited

As liver diseases are a major health problem and especially the incidence of metabolic liver diseases like non-alcoholic fatty liver disease (NAFLD) is rising, the demand for non-invasive tests is growing to replace liver biopsy. Non-invasive tests such as carbon-labelled breath tests can provide a valuable contribution to the evaluation of metabolic liver function. This review aims to critically appraise the value of the (13) C-labelled microsomal breath tests for the evaluation of metabolic liver function, and to discuss the role of cytochrome P450 enzymes in the metabolism of the different probe drugs, especially of aminopyrine. Although a number of different probe drugs have been used in breath tests, the perfect drug to assess the functional metabolic capacity of the liver has not been found. Data suggest that both the (13) C(2) -aminopyrine and the (13) C-methacetin breath test can play a role in assessing the capacity of the microsomal liver function and may be useful in the follow-up of patients with chronic liver diseases. Furthermore, CYP2C19 seems to be an important enzyme in the N-demethylation of aminopyrine, and polymorphisms in this gene may influence breath test values, which should be kept in mind when performing the (13) C(2) -aminopyrine breath test in clinical practice.

Relationship between 13C-aminopyrine breath test and the MELD score and its long-term prognostic use in patients with cirrhosis

BACKGROUND

(13)C-Aminopyrine breath test ((13)C-ABT) is a non-invasive, dynamic, quantitative liver function test, and the model for end-stage liver disease (MELD) is a recognised biochemical score used to predict survival in patients with cirrhosis.

AIMS

The purpose of this study was to evaluate the relationship between the (13)C-ABT and MELD score in a cohort of cirrhotic patients and, moreover, to assess the prognostic value of (13)C-ABT results in the same group of patients.

PATIENTS AND METHODS

Forty-six patients with cirrhosis and without hepatocellular carcinoma who underwent (13)C-ABT and who had at least 1-year follow-up were prospectively included in this study. MELD score was calculated at entry into the study in all patients. End-points of the study were 1-year liver-related death or liver transplantation.

RESULTS

(13)C-ABT %dose/h at 30 min (%dose/h30) results showed significant, inverse correlation with MELD scores (r = -0.414, P = 0.004). During 1-year follow-up nine patients died (19.6 %) and two were transplanted (4.3 %). Median (13)C-ABT %dose/h30 results (3.2 vs. 1.8) were significantly higher in patients who survived as compared to those who died or underwent transplantation (P = 0.04). Receiver operating characteristics curves showed that a (13)C-ABT %dose/h30 cut-off of 2.0 had the best accuracy (c-index = 0.717) in assessing 1-year prognosis.

CONCLUSIONS

We observed a correlation between a flow-independent quantitative liver function test and the MELD score, and found that the (13)C-ABT may accurately provide long-term prognostic information in cirrhotic patients.

13C-aminopyrine demethylation is decreased in cirrhotic patients with normal biochemical markers

This study determined the rates of (13)C-aminopyrine metabolism in patients with varying degrees of liver cirrhosis as defined by clinical scores. Twenty-five cirrhotic patients and 18 healthy subjects underwent a (13)C-aminopyrine breath test. The cumulative per cent dose recovery (cPDR) of (13)C on breath expressed as a percentage of the administered dose at 2 h was significantly lower in cirrhotic patients than in healthy subjects (median: 1.7% versus 9.0%; p<.0001). Significant inverse associations between cPDR at 2 h and the model for end-stage liver disease score, Child-Pugh score, international normalised ratio and bilirubin (all p<.05), but not alanine aminotransferase or alkaline phosphatase were observed in the cirrhotic patients. Taking each biochemical marker independently, cirrhotic patients with normal biochemistry had a significantly lower cPDR at 2 h than healthy subjects (all p<.05). Differences in (13)C-aminopyrine metabolism were evident in cirrhotic patients with less severe disease and may mark hepatic dysfunction when conventional biochemical markers appear unchanged.

Clinical utility of 13C-liver-function breath tests for assessment of hepatic function

13C-Liver-function breath tests have been used in clinical diagnostics and, to a limited extent, to investigate hepatic function. From a practical perspective, tests such as the 13C-aminopyrine and 13C-methacetin breath tests are simple to administer, safe, and relatively inexpensive to perform. Surprisingly, they have not entered the mainstream of clinical practice, because they are perceived to lack the specificity and adequate precision needed to give accurate results in real time. The dynamic nature of 13C-liver-function breath tests, their possible versatility in terms of assessing a range of different liver functions, and the ease with which they can be repeated to follow relative changes in liver function with time, all imply the potential for wider clinical application. Therefore, there is a need for these tests to be critically evaluated and their potential clinical application be tested systematically against defined objectives. We describe refinements in the methodology of the tests and propose several situations in which currently reliable methods for assessment of liver function do not exist and where 13C-liver-function breath tests might be of use. We propose that use has been constrained by practical methodological considerations which could be addressed to offer tests better suited to routine application in the out-patient or community setting.

Galactose half-life is a useful tool in assessing prognosis of chronic liver disease in children

In children, optimal timing of liver transplantation (LT) is crucial, but reliable prognostic tools for chronic liver diseases are scarce. We assessed the predictive value of galactose half-life (Gal½) for LT or death. A retrospective search of hospital database 2003-2010 revealed 92 consecutive children with chronic liver disease (36 biliary atresia) whose liver function was assessed with Gal½ measurement. Gal½, follow-up data, and liver biochemistry were recorded and pediatric/model for end-stage liver disease (P/MELD) scores calculated. Patients listed for LT or those who died within 1 year of the Gal½ measurement (Group 1) were compared to those surviving without listing (Group 2). Predictive value of Gal½ and P/MELD for listing for LT was assessed with area under the receiver operating characteristic curve (AUROC) analysis. Group 1 had markedly increased median Gal½ [17.0 (interquartile range 12.5-28.5) min] and higher P/MELD [13 (-1-23)] compared with group 2, [10.5 (9.5-12.5) min and -1 (-8-8); P < 0.001 for both]. Both Gal½ and P/MELD (P < 0.001) predicted listing or death with respective AUROCs of 0.808 (95% CI 0.704-0.913) and 0.780 (0.676-0.890), and 85% sensitivity and 69% specificity for Gal½≥12.0 min. Gal½ is a useful tool when evaluating 1-year prognosis in children with chronic liver disease.