Prediction of survival in extrahepatic biliary atresia by hepatic duplex sonography

Predicting native liver injury and survival in biliary atresia

Several patient and treatment related factors significantly modify outcomes of biliary atresia. The extremely variable prognosis mandates intensive postoperative monitoring following portoenterostomy. Accurate prediction of outcome and progression of liver injury would enable individualized treatment and follow-up protocols, patient counseling and meaningful stratification of patients into clinical trials. While results on most biomarkers of cholestasis, hepatocyte function, fibrosis and inflammation studied so far are inconsistent or have not been validated in independent patient cohorts, postoperative serum bilirubin level 3 months after portoenterostomy remains the most accurate clinically feasible predictor of native liver survival. Although liver stiffness and a novel marker of cholangiocyte integrity, serum matrix metalloproteinase-7, correlate with liver fibrosis and may discriminate biliary atresia from other causes of neonatal cholestasis, further information on their ability to predict portoenterostomy outcomes is needed. Recent gene expression profiling has shown promise in overcoming the sampling error associated with histological quantification of liver fibrosis, and provides an important possibility to stratify patients for clinical trials according to the prognosis of native liver survival already preoperatively. As activity and extent of ductular reaction is linked with progression of liver fibrosis in cholangiopathies, further research is also warranted to evaluate predictive value of ductular reaction, matrix metalloproteinase-7 and the underlying gene expression signatures in relation to circulating bile acids in biliary atresia. Discovery of accurate predictive tools will ultimately increase our understanding of the unpredictable response to surgery and pathophysiology of progressive liver injury in biliary atresia.

Diagnostic Performance of Sonographic Features in Patients With Biliary Atresia: A Systematic Review and Meta-analysis

OBJECTIVES

To evaluate the diagnostic performance of sonographic features of biliary atresia in patients with infantile cholestasis.

METHODS

The Ovid-MEDLINE and EMBASE databases were searched for studies of the diagnostic performance of sonographic features of biliary atresia in patients with infantile cholestasis. A meta-analysis was performed to evaluate the diagnostic performance of the triangular cord sign and other sonographic features in patients with biliary atresia.

RESULTS

Seventeen eligible studies with 1444 patients were included. The triangular cord sign had high accuracy for diagnosing biliary atresia: the meta-analytic summary sensitivity and specificity were 85% (95% confidence interval, 77%-90%) and 97% (95% confidence interval, 94%-99%), respectively. The area under the hierarchical summary receiver operating characteristic curve was 0.97. Meta-regression analysis revealed that the cutoff thickness of the triangular cord sign (3 or 4 mm) was a significant factor affecting study heterogeneity (P < .01). The proportions of nonidentification of the gallbladder (GB) ranged from 0% to 53%. Abnormal GB morphologic characteristics, nonvisualization of the common bile duct, and the presence of hepatic subcapsular flow showed relatively high sensitivities and specificities.

CONCLUSIONS

The triangular cord sign and other sonographic features, including abnormal GB morphologic characteristics, nonvisualization of the common bile duct, and the presence of hepatic subcapsular flow, had high diagnostic performance for the diagnosis of biliary atresia.

Value of duplex doppler ultrasonography in non-invasive assessment of children with chronic liver disease

AIM: To investigate the value of duplex Doppler ultrasonography (US) in the assessment of the hemodynamics of the portal and hepatic veins in a cohort of children with chronic liver disease (CLD) and to detect any relationship between the US changes, etiology and severity (or stage) of CLD.

METHODS: We prospectively enrolled 25 children with biopsy-proven CLD. Thirteen had cirrhosis (aged 8.9 ± 2.0 years) and 12 had chronic hepatitis (aged 9.3 ± 2.3 years). Gray scale and color-coded duplex Doppler US were performed for all, as well as 30 healthy age and sex-matched controls. Findings were correlated with clinical, laboratory and histopathological characteristics.

RESULTS: Prominent caudate lobe was detected in 100% of cirrhotics, but none of the chronic hepatitis or controls. Thickened lesser omentum and loss of the triphasic waveform of the hepatic vein were present in 69.2% and 53.8% of cirrhotics vs 33.3% and 8.3% of chronic hepatitis respectively. Portal vein flow velocity was significantly lower (P < 0.0001) and the congestion index was significantly higher (P < 0.005) in both patient groups compared to controls. Child-Pugh’s staging showed a positive correlation with both abnormal hepatic vein waveform and direction of portal blood flow; and a negative correlation with both hepatic and portal vein flow velocities. No correlation with the etiology of CLD could be detected.

CONCLUSION: Duplex Doppler added to grayscale US can detect significant morphologic and portal hemodynamic changes that correlate with the severity (stage) of CLD, but not with etiology.

Paediatric chronic liver diseases: how to investigate and follow up? Role of imaging in the diagnosis of fibrosis

Chronic liver diseases are rare in children, but encompass a wide spectrum of disorders that may all be complicated by liver fibrosis and therefore by portal hypertension. They may be classified according to the level of portal flow obstruction: prehepatic, intrahepatic or suprahepatic. Most of them, except presinusoidal diseases, may progress to cirrhosis that carries additional risks of impaired liver function and development of hepatocellular carcinoma. Imaging plays an important role in guiding the diagnosis and biopsy and for follow-up during treatment. US, with high-frequency transducers and Doppler, is the first modality of choice, directs the rest of the investigations and guides interventional radiology. MDCT has made great progress and has replaced angiography for diagnostic purposes. MRI is indicated for parenchyma and nodule characterization and for biliary tract evaluation. To avoid liver biopsy, several elasticity imaging techniques have been developed and have to be evaluated for accuracy and convenience in children. The role of each modality with main imaging findings is described in extrahepatic portal vein obstruction, hepatoportal sclerosis, congenital hepatic fibrosis, cirrhosis and Budd-Chiari syndrome.

Direct measurement of hepatic blood flow during living donor liver transplantation in children

BACKGROUND

The changes in liver blood flow associated with living donor liver transplantation (LDLT) in children have not yet been studied. The aim of the present study was to investigate changes in hepatic hemodynamics before and after pediatric partial liver transplantation.

METHODS

In 7 pediatric recipients with congenital cholestasis and native liver Child-Pugh classes B and C, portal vein flow (PVF) and hepatic arterial flow (HAF) were measured using an ultrasonic transit time flow meter before removal of the native liver and after transplantation and compared with donor left PVF and donor left HAF.

RESULTS

The mean portal contribution to total hepatic blood flow was markedly decreased in the recipient native liver compared with that in the donor (69% +/- 15% vs 32% +/- 15%; P = .0003) and after reperfusion changed to almost the same ratio as that in the donor liver (73% +/- 18%; P < .0001).

CONCLUSION

The extreme imbalance between PVF and HAF that is common in implanted partial liver in adult LDLT recipients was not observed in pediatric LDLT. After transplantation of an appropriately sized liver graft, the portal contribution to total liver blood flow normalized to the value for normal liver.

Prognostic value of computerized quantification of liver fibrosis in children with biliary atresia

Biliary atresia (BA) is the leading indication for liver transplantation (LTx) during childhood. Predictive markers for progression are lacking. We investigated the correlation between quantified fibrosis of the liver at the time of Kasai hepatic portoenterostomy (KPE) and the clinical course. Liver tissue was obtained at the time of KPE in 53 children and stained with Picrosirius red. The mean volume of fibrosis per number of periportal fields (Vfib) and the Ishak score were calculated. Vfib was 3.9%. Transplant-free survival was significantly higher in those patients with Vfib < 2.5% (P < 0.05, Kaplan-Meier analysis). Vfib < 2.5% predicted transplant-free survival with a sensitivity of 100% and a specificity of 48% (positive predictive value: 100%, negative predictive value: 17%). Vfib was correlated with bilirubin 6 months after KPE (Bili6m). The negative predictive value could be enhanced to 23% if Vfib < 2.5% was combined with Bili6m < 20 micromol/L. The Ishak score showed no correlation with transplant-free survival or Vfib. Detection of Vfib at the time of KPE is a valid marker in predicting transplant-free survival in children with BA. This method should be considered an integral part of scoring systems predicting the indication for LTx. Liver Transpl 15:876-882, 2009. (c) 2009 AASLD.

Medial thickening of hepatic artery branches in biliary atresia. A morphometric study

BACKGROUND/PURPOSE

Medial layer hypertrophy of hepatic arterial branches may be associated with biliary atresia (BA) pathogenesis. This study aimed at evaluating medial layer thickness in hepatic arterial branches at portoenterostomy and liver transplantation.

METHODS

The authors evaluated 1274 arterial branches both in BA cases and in control subjects involving a total of 1108 arterioles and 166 arteries. Arterial branch characteristics were morphometrically evaluated in 47 BA patients at the time of portoenterostomy. Controls were patients with intrahepatic cholestasis (n = 3), immature neonates (n = 7), and infants (n = 7) without liver disease. Progression of medial layer thickening between the time of portoenterostomy and transplantation was evaluated in 7 BA patients. Biliary atresia patients at the time of transplantation were compared with non-BA-transplanted patients (n = 4).

RESULTS

The arterial medial layer of BA cases at portoenterostomy was thicker than that of infants without liver disease ( P = .03). The arterial medial thickness increased during the interval between portoenterostomy and transplantation ( P = .05). Arterioles and arteries with thickened medial layers were found in transplanted BA patients but not in patients transplanted for other liver diseases (P = .05 and P = .01). Thickening of the medial layer of the hepatic arteries was associated with focal distribution of interlobular bile ducts in portal spaces in BA ( P = .02).

CONCLUSIONS

In BA, there is a progressive thickening of the arterial medial layer, suggestive of vascular remodeling, which is associated to the disappearance of interlobular bile ducts.

Biliary atresia

Biliary atresia (BA) is a congenital obliterative cholangiopathy of unknown aetiology, affecting both the intra- and extrahepatic bile ducts. Although relatively rare, BA must be excluded in any infant with conjugated hyperbilirubinaemia since the prognosis is improved by early diagnosis and prompt surgery. At least two phenotypes of BA are currently recognized; the syndromic variety is associated with other congenital anomalies and a poorer outcome. The results of treatment have steadily improved and, with a combination of timely expert surgery (Kasai portoenterostomy) and liver transplantation in specialist centres, good quality long-term survival is now possible in more than 90% of affected patients. A better understanding of the aetiology of BA and the pathogenesis of hepatic fibrosis is needed in order to develop new therapeutic strategies.

Validation of ultrasonography for hepatic schistosomiasis using a porcine Schistosoma japonicum model

Ultrasonography is increasingly used to record hepatosplenic involvement in schistosomiasis. However, questions remain unsolved regarding diagnostic accuracy in mild hepatic disease and under influence of confounders like co-infections. We report on a study to evaluate the suitability of a pig model of schistosomiasis japonica to investigate such problems. Nine pigs (12 weeks of age) were infected with 1000 Schistosoma japonicum cercariae. Together with 10 uninfected controls, they underwent B-mode and Doppler ultrasonography 12 weeks after infection, followed by parasitological and gross pathological examination and quantification of hepatic collagen. At this time, all infected pigs had patent infection, hepatic displacement of ova and various grades of portal and septal liver fibrosis. Sonographically, echogenic portal thickening (ePT), increased hepatic echogenicity (EG), increased hepatic dimensions and dilatation of the portal vein were found to correlate with other parameters of morbidity. Algorithms from human medicine were appropriate to grade ePT in the pig model. It is concluded that the porcine model of schistosomiasis japonica can be instrumental in approaching problems which for any reasons cannot be studied in human beings.

Plasma endothelin-1 concentrations in children with cirrhosis and their relationship to renal function and the severity of portal hypertension

BACKGROUND

Plasma endothelin-1 (ET-1) is a potent vasoconstrictor peptide involved in the pathogenesis of several disorders. Endothelin-1 concentrations are increased in adult patients with cirrhosis. However, little is known about ET-1 concentrations in children with cirrhosis.

METHODS

Radioimmune assay was used to measure plasma ET-1 concentrations in 19 children with cirrhosis (8 patients with ascites, and 11 without ascites), and 11 age- and sex-matched healthy children. The plasma ET-1 concentrations were correlated with the mean blood pressure, creatinine clearance, and severity of portal hypertension, as measured by portal flow volume and portal flow velocity.

RESULTS

Patients with cirrhosis and ascites had increased plasma ET-1 concentrations compared with patients who did not have ascites (6.8 pg/mL +/- 0.62 pg/mL vs. 4.6 pg/mL +/- 0.35 pg/mL; mean +/- SEM; < 0.01) and controls (3.6 pg/mL +/- 0.27 pg/mL; mean +/- SEM; < 0.0005). Plasma ET-1 concentrations were higher in patients with cirrhosis who did not have ascites compared with controls ( < 0.005). No significant differences were observed between concentrations of the patients with cholestasis and those without cholestasis (5.4 pg/mL +/- 0.52 pg/mL vs. 5.2 +/- 0.32 pg/mL; mean +/- SEM; = 0.1). Plasma ET-1 concentrations correlated positively with the mean blood pressure ( = 0.58; < 0.05) and negatively with renal function, as measured by creatinine clearance ( = -0.7; <0.005). However, no correlation was detected between ET-1 concentrations and portal flow volume ( = -0.02; = 0.4) or portal flow velocity ( = -0.16; = 0.4).

CONCLUSIONS

Plasma ET-1 concentrations are increased in children with cirrhosis, with or without ascites, compared with controls. Patients with cirrhosis and ascites have increased ET-1 concentrations compared with those without ascites. The degree of increase does not relate to the severity of portal hypertension. This increase tends to maintain systemic blood pressure but is associated with a decrease in renal function.

Is the Kasai operation still indicated in children older than 3 months diagnosed with biliary atresia?

OBJECTIVES

The prognosis of hepatoportoenterostomy (the Kasai operation) for biliary atresia worsens when the age at surgery increases. This study examines whether the Kasai operation remains justified after 3 months of life.

STUDY DESIGN

Records for all patients with biliary atresia living in France and born in the years 1986 to 1996 were reviewed, and patients were classified into 3 groups: group 1 (n = 30), no contraindication to the Kasai operation, but orientation to de novo transplantation; group 2 (n = 380), age at Kasai operation <90 days; and group 3 (n = 60), age at Kasai operation > or =90 days. Survival with native liver, survival after liver transplantation, and overall survival (Kaplan-Meier method) were compared by using the log-rank test.

RESULTS

Five-year (10-year) survival with native liver was 35% (30%) in group 2 and 25% (22%) in group 3 (P =.03). Five-year overall survival was 57%, 74%, and 55% in groups 1, 2, and 3, respectively (P =.003). Poor results in groups 1 and 3 were mainly due to increased pre-transplantation mortality, but survival after transplantation was not significantly different in the 3 groups.

CONCLUSIONS

Performance of the Kasai operation after 3 months of age is justified in selected cases, because it may obviate liver transplantation. Preoperative evaluation should exclude patients with advanced liver disease for whom liver transplantation should not be delayed.

Biliary atresia. A surgical perspective

The combination of portoenterostomy with subsequent liver transplantation is the treatment of choice for patients with biliary atresia. It is important, however, to attempt to keep the patient's own organ by continuing efforts to achieve the best possible results with portoenterostomy. Additional basic research, perhaps concerning on the role of cytokines and apoptosis in the control of biliary atresia, may provide insight into possible new medical strategies for treating patients with biliary atresia. For example, in addition to portoenterostomy, control of apoptosis at various cellular levels and of bile duct cell proliferation and maturation by manipulation of the growth factors and cytokines may become part of future treatment modalities. Another direction of research should be the control of fibrogenesis, which might be accomplished by blocking TGF-beta 1 and platelet-derived growth factor and by HGF gene therapy. The author's current strategy for surgical treatment for patients with biliary atresia include (1) early diagnosis, including prenatal diagnosis and broader use of mass screening programs, (2) hepatic portoenterostomy, without stoma formation; (3) close postoperative care, especially for prevention of postoperative cholangitis; (4) revision of portoenterostomy only in selected cases; (5) early liver transplantation in patients with absolutely failed portoenterostomy; (6) avoidance of laparotomy for the treatment of esophageal varices and hypersplenism; (7) consideration of exploratory laparotomy or primary liver transplantation for patients with advanced liver disease at the time of referral. The development of new treatment modalities based on the understanding of the pathogenesis of the disease, and especially on the biology of intrahepatic bile ducts and hepatic fibrosis, is essential.