Aminopyrine breath test in the prognostic evaluation of patients with cirrhosis

Prognostic usefulness of ultrasonographic signs of portal hypertension in patients with child-pugh stage A liver cirrhosis

OBJECTIVE

The aim of this study was to identify factors related with mortality in patients with cirrhosis in the absence of habitual biochemical markers of liver dysfunction.

METHODS

Seventy-five cirrhotic patients in Child-Pugh stage A, without hepatocellular carcinoma, were followed until death or the end of the study period. We analyzed the association between cumulative survival and 15 variables determined at the moment of inclusion: age, sex, time from diagnosis of cirrhosis, alcohol abuse, history of variceal bleeding, hepatitis B and C virus infection, Child-Pugh score, plasma albumin and bilirubin levels, prothrombin activity, and four sonographic parameters (size of liver, portal vein diameter, size of spleen, and presence of collateral circulation).

RESULTS

Mean follow-up was 38.7+/-10 months. Eighteen patients died. Four-year cumulative survival was 77.4+/-5%. Only five variables had a significant influence on survival according to log-rank test: sex, previous variceal bleeding, hepatitis B virus infection, portal vein diameter, and size of the spleen. Multivariate Cox's model showed male sex (relative risk 4.6; 95% confidence interval 1.2-16.8) and diameter of the portal vein > 13 mm, splenomegaly > 145 mm, or both together (relative risk 6.0; 95% confidence interval 1.3-27.2) as independent predictors of the risk of death.

CONCLUSIONS

Child-Pugh stage A cirrhotic patients have substantial variability in mid-term survival. Ultrasonography is a useful aid in establishing their prognosis. Men with dilation of the portal vein, splenomegaly, or both, form a group with a significantly higher risk of death.

Comparison between the oral and intravenous L-[1-13C]phenylalanine breath test for the assessment of liver function

To simplify the L-[1-13C]phenylalanine breath test which is used to assess liver function the tracer is usually given orally, and CO2 production rate is estimated. In 12 healthy volunteers and 10 liver cirrhotics we compared the oral approach with i.v. tracer administration combined with measurement of individual CO2 production rate. The 13CO2/12CO2 enrichment was assessed by isotope-ratio mass spectrometry. After i.v. [1-13C]phenylalanine application exhaled 13C recovery per minute peaked within 10 minutes (controls: 0.17 +/- 0.06%; cirrhotics: 0.05 +/- 0.02%, p < 0.01). The oral approach yielded comparable separation between 30-60 minutes, with average peak values being 0.18 +/- 0.03% and 0.06 +/- 0.03% (p < 0.01), respectively. Variable gastrointestinal resorption kinetics after oral application probably causes this difference.

Evaluation of preoperative hepatic function in patients with hepatocellular carcinoma undergoing hepatectomy

BACKGROUND

Postoperative hepatic failure is the leading cause of hospital mortality following hepatectomy for hepatocellular carcinoma (HCC). This prospective study was performed to identify the best test for assessment of the adequacy of hepatic functional reserve in patients with HCC before hepatectomy.

METHODS

Between April 1989 and June 1993, 127 patients with HCC underwent hepatectomy. Each patient was evaluated before operation with the indocyanine green (ICG) clearance test, the aminopyrine breath test and the amino acid clearance test.

RESULTS

Fourteen patients (11 per cent) died after hepatectomy. ICG retention at 15 min showed significant differences between patients who survived or died. By discriminant analysis, the safety limit of ICG retention at 15 min for major hepatectomy was 14 per cent and the relative risk of hospital mortality was 3.

CONCLUSION

The ICG clearance test, expressed as the percentage of ICG retained at 15 min, is the best discriminating preoperative test for evaluating hepatic functional reserve in patients with HCC before hepatectomy.

Evaluation of preoperative hepatic function in patients with hepatocellular carcinoma undergoing hepatectomy

BACKGROUND

Postoperative hepatic failure is the leading cause of hospital mortality following hepatectomy for hepatocellular carcinoma (HCC). This prospective study was performed to identify the best test for assessment of the adequacy of hepatic functional reserve in patients with HCC before hepatectomy.

METHODS

Between April 1989 and June 1993, 127 patients with HCC underwent hepatectomy. Each patient was evaluated before operation with the indocyanine green (ICG) clearance test, the aminopyrine breath test and the amino acid clearance test.

RESULTS

Fourteen patients (11 per cent) died after hepatectomy. ICG retention at 15 min showed significant differences between patients who survived or died. By discriminant analysis, the safety limit of ICG retention at 15 min for major hepatectomy was 14 per cent and the relative risk of hospital mortality was 3.

CONCLUSION

The ICG clearance test, expressed as the percentage of ICG retained at 15 min, is the best discriminating preoperative test for evaluating hepatic functional reserve in patients with HCC before hepatectomy.

Xenobiotic-induced hepatotoxicity: mechanisms of liver injury and methods of monitoring hepatic function

Xenobiotic-induced liver injury is a clinically important etiology of hepatic disease that, if not recognized, can lead to hepatic failure. In this article we discuss the mechanisms of xenobiotic-induced liver injury, various factors that can alter the risk and severity of injury, the clinical and laboratory manifestations of injury, and the methods used to detect the presence of injury and (or) functioning liver mass.

Prognostic evaluation of patients with parenchymal cirrhosis. Proposal of a new simple score

BACKGROUND/AIMS

The current shortage of organs makes it desirable to establish the prognosis of patients with cirrhosis in order to assess priority for liver transplantation.

METHODS

We compared the utility of two exogenous tests (aminopyrine breath test and lidocaine metabolization test), two clinical parameters (encephalopathy, ascites), 18 endogenous tests and five scores (Pugh, Merkel, Orrego, Adler, Pignon) for predicting 1-year mortality in patients with parenchymal cirrhosis. Retrospective (n=49 out of 63 patients) and prospective (n=38 out of 46 patients) series were included. Univariate, multivariate, receiver operator curves and survival curves were employed.

RESULTS

We found that endogenous tests were more discriminant than exogenous tests. The best parameters of the univariate analysis (encephalopathy, bilirubin, alkaline phosphatase, cholinesterase and bile acids) and their 25th and 75th percentiles were included in an additive new score which turned out to be superior to the five other scores. Prospectively, the sensitivity of our new score compared to the Pugh score was 82% versus 95% (NS) and the specificity was 89% versus 56% (p<0.01).

CONCLUSIONS

Our new simple score appears to be very powerful for predicting prognosis at 1 year for patients with cirrhosis and should be evaluated in other centers.

Continuous monitoring of 13C-aminopyrine metabolism in rats: effects of cold exposure and noradrenaline

A system was developed to allow constant monitoring of hepatic cytochrome P450 activity in awake and unrestrained rats. A continuous 13C-aminopyrine perfusion was performed, and breath samples obtained for endogenous CO2 production and 13C measurements, to calculate 13C O2 production due to aminopyrine demthylation. Increasing doses of 13C-aminopyrine produced a hyperbolic increase of expired 13CO2, compatible with an in vivo measurement of enzymatic activity. Acute-cold exposure of the rats during 13C-aminopyrine perfusion produced a two-fold increase of endogenous CO2 production, together with a 27% increased 13C-aminopyrine metabolism (p<0.05 vs basal conditions). In contrast, noradrenaline (20 microg/kg BW/min), despite a similar effect on energy expenditure, did not significantly change 13C-aminopyrine metabolism. Acute-cold exposure is known to stimulate both adrenal catecholamine secretion and the sympathetic nervous system. The observed difference in 13C-aminopyrine demthylation during cold exposure and nonadrenaline perfusion, therefore, could be due to a more specific effect of adrenal catecholamines on liver aminopyrine metabolism. These results suggest the possibility of prolonged in vivo monitoring of liver metabolism pathways such as aminopyrine demethylation, thus allowing the study of drug acute interactions with cytochrome P450 system.

Liver function tests

For optimal timing of liver transplantation and for the evaluation of new pharmacotherapeutic options, objective modalities for estimating the liver's functional reserve and prognosis in an individual patient are highly desirable. In the past a number of tests and several scoring systems have been proposed and validated to varying degrees for this purpose. The issues still to be clarified include: (1) any observed prognostic value of individual quantitative function tests and of scoring systems must be validated in independent, large enough and well defined patient populations; (2) it must be prospectively defined which (serially performed) quantitative test(s) add(s) prognostic information for the individual patient to the survival estimates defined by the more universally available scores and in which disease state(s); and (3) existing scoring systems must be validated, or new ones developed, that allow follow-up data to be used in order to adapt the original prognosis estimate to the evolution of the disease, e.g. during therapy.

Metabolism of aminopyrine and derivatives in man: in vivo study of monomorphic and polymorphic metabolic pathways

1. The main metabolic pathways involved in the biodisposition of aminopyrine have been monitored in vivo in 60 healthy volunteers by measuring the amount of parent drug and metabolites recovered in the urine 24 h after oral administration of 250 mg aminopyrine. 2. The amount of metabolites in the 24-h urine was (mean +/- SD of 60 individuals): unchanged aminopyrine, 0.2 +/- 0.2 mg; methyl aminoantipyrine, 4.5 +/- 2.8 mg; formyl aminoantipyrine, 18.5 +/- 10.1 mg; aminoantipyrine, 9.2 +/- 6.6 mg; and acetyl aminoantipyrine, 31.8 +/- 21.1 mg. 3. Large interindividual differences (12-200-fold changes) are present in all the metabolic steps involved in aminopyrine biotransformation. These differences are not related to gender, intake of caffeine or alcohol, or known drug-metabolizing polymorphisms such as those involved in debrisoquine or mephenytoin metabolism. In contrast, smoking resulted in a decrease in the N(4)-demethylation ratio (p = 0.011). 4. The interindividual differences followed an apparently normal distribution in the N(4)- and N(2)-dimethylation and formylation pathways (p > 0.1). In contrast, acetylation follows a polymorphic distribution (p < 0.03), with an apparent antimode ratio close to 4. With the exception of the acetylation pathway, all of the metabolic ratios correlated between themselves (p < 0.001).

Aminopyrine breath test improves long-term prognostic evaluation in patients with alcoholic cirrhosis in Child classes A and B

In a 4-year survival study, we evaluated the prognostic value of the aminopyrine breath test and the Child-Turcotte-Pugh score in 190 alcoholic patients. Using aminopyrine breath test results, the patients were stratified into group 1 (aminopyrine breath test > 2%), group 2 (1% < or = aminopyrine breath test < 2%) and group 3 (aminopyrine breath test < 1%). Survival rates at 4 years were 68% in group 1, 35% in group 2 and 17% in group 3. Using the Child-Turcotte-Pugh score, survival rates at 4 years were 67% in Child-Turcotte-Pugh class A, 40% in class B and 7% in class C. To assess the value of aminopyrine breath test as an adjunct to Child-Turcotte-Pugh score in prognostic evaluation of patients with cirrhosis, two approaches have been used: a regression analysis using Cox's proportional hazard model by including the Child-Turcotte-Pugh score and aminopyrine breath test value, and the log-rank test to assess the prognostic value of aminopyrine breath test in each Child-Turcotte-Pugh class separately. The regression analysis showed that both parameters, the Child-Turcotte-Pugh score and the aminopyrine breath test results, were accepted in the model, suggesting that the aminopyrine breath test was still significantly related to survival once the Child-Turcotte-Pugh score had been entered into the model. Analysis of the prognostic value of the aminopyrine breath test in each Child-Turcotte-Pugh class separately indicated, however, that the contribution was negligible in the Child-Turcotte-Pugh class C.(ABSTRACT TRUNCATED AT 250 WORDS)