Portal venous pressure in biliary atresia

A new criterion including the aspartate aminotransferase-to-platelet ratio index and liver and spleen stiffness to rule out varices needing treatment in children with biliary atresia: Modification of the Baveno VII criteria

AIMS

Biliary atresia (BA) is a congestive biliary disease that develops in the neonatal period or early infancy. It may present with portal hypertension and varices needing treatment (VNT) even after successful Kasai portoenterostomy. This study aimed to stratify the risk of VNT in children and adolescents with BA.

METHODS

In this prospective cross-sectional study, we measured liver stiffness (LS) and spleen stiffness (SS) by two-dimensional shear wave elastography and checked for VNT endoscopically in 53 patients with BA who attended for follow-up between July 2018 and September 2022. Varices needing treatment were defined as large esophageal varices, esophageal varices of any size with red color signs, and/or gastric varices along the cardia.

RESULTS

Twenty-five patients (aged 0-18 years) had VNT. Eighteen patients met the Baveno VI criteria (LS <20 kPa; platelet count >150 000/L) and were deemed to be at low risk of VNT (spared endoscopies) while three had missed VNT (16.7%). Applying the Baveno VII criteria, which combines the SS cut-off value of 40 kPa with the Baveno VI criteria, resulted in five missed VNTs among 22 spared endoscopies (22.7%). A modification of the Baveno VII criteria using the aspartate aminotransferase-to-platelet ratio index (APRI) instead of the platelet count with cut-off values of 25 kPa, 30 kPa, and 1.04 for LS, SS, and APRI, respectively, missed only one VNT (5.0%) among 20 spared endoscopies.

CONCLUSIONS

A novel diagnostic criterion that combines LS, SS, and APRI reduced the risk of missing VNT to 5% in children and adolescents with BA.

Portal vein pressure and flow modulation in pediatric liver transplantation

Liver transplantation (LT) has been indicated for smaller and more clinically severe patients in recent years. Small biliary atresia (BA) patients often show portal hypoplasia and sclerotic portal vein (PV), which may make PV reconstruction more difficult during the operation. Among PV complications, intraoperative PV thrombosis can be considered a disaster, and it is important to prevent this catastrophic event by the precise assessment of the PV structure and PVF using radiological imaging before and during LT. However, there are no objective parameters to indicate whether sufficient PVF can be obtained. PV pressure (PVP) and PV flow (PVF) have mainly been studied in adult living donor LT, for the purpose of preventing small-for-size syndrome, and PVP has been considered an objective parameter of graft inflow modulation (GIM). In the setting of pediatric LT, GIM is mainly performed to prevent hypoperfusion, and it must be performed before graft implantation. GIM to maximize the PVF of pediatric patients with potentially low PVF in LT consists of the interruption of collateral vessels, the assessment of the usability of the native PV, and technical modifications in PV reconstruction. Reliable objective parameters that represent sufficient PVF before graft implantation are desired. Our recent study proposed that a PVP of ≥25 mmHg before graft implantation can be considered an objective parameter to obtain sufficient PVF (cutoff value: 50 mL/min/100 g of graft weight). Further investigation is needed to determine the best strategy for successful PV reconstruction in pediatric LT.

What Makes A "Successful" Kasai Portoenterostomy "Unsuccessful"?

OBJECTIVES

Clearance of jaundice (CoJ) is the first key objective of Kasai portoenterostomy (KPE) for biliary atresia (BA) and its achievement is by far the best index of long-term prognosis. We sought to identify the reasons for failure [subsequent liver transplant (LT)] in this cohort.

METHODS

Review of single-center prospective BA database. Successful KPE was defined by achieving a postoperative bilirubin of ≤20 µmol/L. Pre-KPE and post-KPE variables were identified together with a multivariate logistic regression model to identify those observable at 3 months post-KPE. Data are quoted as median (range). A P value of ≤0.05 was significant.

RESULTS

One hundred thirty-five infants underwent KPE between January 2012 and December 2018, of which 90 (67%) achieved CoJ. From these 20 (22%) (Cohort A) underwent LT with the remainder continuing with native liver (Cohort B) (median follow-up of 4.15 years). There was no difference in age at KPE ( P = 0.41), APRi (aspartate aminotransferase-to-platelet ratio) ( P = 0.07), associated anomalies ( P = 0.7), and cytomegalovirus status ( P = 0.7) between the 2 groups. Postoperatively, both cholangitis [any episode, 18/20 (90%) vs 15/70 (21%); P < 0.0001] and portal hypertension (PHT) [gastrointestinal (GI) bleed, 10/20 (50%) vs 2/70 (2.8%); P < 0.0001] were significantly more common in cohort A. Univariate analysis showed that the most significant predictive values at 3 months for LT by 2 years were high APRi, bilirubin, international normalized ratio, and ultrasound (US)-detected ascites with multivariate logistic modeling confirming these variables with predictive values of r2 = 0.79, AUROC = 0.98.

CONCLUSIONS

Failure is not preordained at KPE but due to recurrent cholangitis and/or symptoms of PHT.

Unusual Clinical Course for Untreated Malformative Biliary Atresia Infant: Is Portal Hypertension an Important Driver of Liver Fibrosis?

In biliary atresia, infants left untreated, and in those with unsuccessful porto-enterostomy, hepatic condition and function worsen rapidly towards cirrhosis, malnutrition, portal hypertension with ascites, and variceal haemorrhage; many die within the first 3 years of life unless they benefit from liver replacement. We describe a girl with biliary atresia splenic malformation syndrome, who had portal vein cavernoma and microsplenia; she did not undergo porto-enterostomy. She survived with her native liver over the age of 3 years. Remarkably, she remained in satisfactory condition in absence of ascites or severe hepatic dysfunction, when 4 other similar patients-managed during the same period of time-all had the usual clinical deterioration and ascites, with the need for liver replacement. To our knowledge, there is no similar report in literature. Possible pathogenetic mechanisms and the role of portal hypertension as important factors are discussed.

Predicting gastroesophageal varices through spleen magnetic resonance elastography in pediatric liver fibrosis

BACKGROUND

A recent retrospective study confirmed that hepatic stiffness and splenic stiffness measured with magnetic resonance elastography (MRE) are strongly associated with the presence of esophageal varices. In addition, strong correlations have been reported between splenic stiffness values measured with MRE and hepatic venous pressure gradients in animal models. However, most studies have been conducted on adult populations, and previous pediatric MRE studies have only demonstrated the feasibility of MRE in pediatric populations, while the actual clinical application of spleen MRE has been limited.

AIM

To assess the utility of splenic stiffness measurements by MRE to predict gastroesophageal varices in children.

METHODS

We retrospectively reviewed abdominal MRE images taken on a 3T system in pediatric patients. Patients who had undergone Kasai operations for biliary atresia were selected for the Kasai group, and patients with normal livers and spleens were selected for the control group. Two-dimensional spin-echo echo-planar MRE acquisition centered on the liver, with a pneumatic driver at 60 Hz and a low amplitude, was performed to obtain hepatic and splenic stiffness values. Laboratory results for aspartate aminotransferase to platelet ratio index (APRI) were evaluated within six months of MRE, and the normalized spleen size ratio was determined with the upper normal size limit. All Kasai group patients underwent gastroesophageal endoscopy during routine follow-up. The Mann-Whitney U test, Kendall's tau b correlation and diagnostic performance analysis using the area under the curve (AUC) were performed for statistical analysis.

RESULTS

The median spleen MRE value was 5.5 kPa in the control group (n = 9, age 9-18 years, range 4.7-6.4 kPa) and 8.6 kPa in the Kasai group (n = 22, age 4-18 years, range 5.0-17.8 kPa). In the Kasai group, the APRI, spleen size ratio and spleen MRE values were higher in patients with portal hypertension (n = 11) than in patients without (n = 11) (all P < 0.001) and in patients with gastroesophageal varices (n = 6) than in patients without (n = 16) (all P < 0.05), even though their liver MRE values were not different. The APRI (τ = 0.477, P = 0.007), spleen size ratio (τ = 0.401, P = 0.024) and spleen MRE values (τ = 0.426, P = 0.016) also correlated with varices grades. The AUC in predicting gastroesophageal varices was 0.844 at a cut-off of 0.65 (100% sensitivity and 75% specificity) for the APRI, and 0.844 at a cut-off of 9.9 kPa (83.3% sensitivity and 81.3% specificity) for spleen MRE values.

CONCLUSION

At a cut-off of 9.9 kPa, spleen MRE values predicted gastroesophageal varices as well as the APRI and spleen size ratio in biliary atresia patients after the Kasai operation. However, liver MRE values were not useful for this purpose.

Non-Invasive Predictors for the First Variceal Hemorrhage in Children With Biliary Atresia After Kasai Portoenterostomy

BACKGROUND/AIM

: Portal hypertension and variceal hemorrhage (VH) are significant complications in biliary atresia (BA). The study aims to evaluate risk factors and noninvasive markers that predict actual VH for the first time in children with BA without prior endoscopic surveillance or treatment.

METHODS

Retrospective review was performed of patients diagnosed with BA from 1989 to 2016 at a single center. Primary outcome was the first episode of VH. Patients were stratified into VH and non-VH groups according to the development of VH, and laboratory and ultrasonographic data were analyzed at 2 time points: pre-VH and the last follow-up. Existing indices, varices prediction rule (VPR), and aspartate aminotransferase (AST)-platelet ratio index (APRI) were also applied retrospectively to evaluate their performance in prediction of VH in our cohort.

RESULTS

Seventy-two patients were included; 16 patients developed the first VH at median age of 5.5 years. On univariate analysis, serum albumin (P = 0.034), AST (P = 0.017), hemoglobin (P = 0.019), platelet count (P = <0.001), spleen size Z-score (P = <0.001), and rate of splenic enlargement (P = 0.006) were associated with VH. On multivariable regression analysis, only platelet count was independently predictive (P = 0.041). The optimal cutoff values for prediction of the first VH were platelet count ≤100 × 10⁹/L (sensitivity 75.0%, specificity 80.4%, positive predictive value [PPV] 52.2%, negative predictive value [NPV] 91.8%), VPR ≤3.0 (sensitivity 81.3%, specificity 85.7%, PPV 61.9%, NPV 94.1%), and APRI ≥3.0 (sensitivity 81.3%, specificity 76.8%, PPV 50.0%, NPV 93.5%).

CONCLUSIONS

Platelet count <100 × 10⁹/L and VPR <3.0 are simple, reproducible and effective noninvasive markers in predicting the first episode of acute VH in children with BA and may be used in pediatrics for the selection of patients to undergo primary prophylactic endoscopic therapy.

Long-term outlook in biliary atresia

The oldest survivors from the Kasai portoenterostomy originate in Sendai, Japan and are approaching their 60th birthday. These represent the tip of an expanding cohort of adults born with this previously fatal condition. Increasingly transition to adult-biased hepatologists and physicians will be the expectation of many with this condition. However unlike their usual patients with alcohol, drugs, virally mediated liver disease these are different with different expectations of health and quality of life. Cure is not on the cards for most of these and they survive still with impaired bile flow and increased liver fibrosis and cirrhosis with the threat of cholangitis and portal hypertension still apparent. We review the reported statistics on long-term survival essentially from Japan and Western Europe (such as the UK and France) and the range of complications that may still beset this group.

Portal pressure and blood nitric oxide levels as predictors of outcome in biliary atresia

Aim:

To evaluate the incidence of portal hypertension (PHT) in biliary atresia (BA) patients and to monitor its progress after Kasai portoenterostomy (KP) by measuring nitric oxide (NO) levels in peripheral blood.

Materials and Methods:

A prospective cross-sectional study conducted over a period of 2 years. Intraoperative portal pressure (PP) and blood NO levels at presentation, 1-month, 3-month, and 6-month follow-up, were correlated with clinical and biochemical parameters in BA patients. The mean NO level in age-matched control group was 4.64 ± 2.32 μmol/L.

Results:

Thirty-four BA patients underwent KP over a period of 2 years. The mean age of presentation was 2.7 months (range 1-4 months). The mean intraoperative PP was 21.3 ± 5.4 mmHg. The mean PP in patients aged <60 days, 61–90 days, and >90 days was 18.53 ± 4.45 mmHg, 20.33 ± 3.07 mmHg, and 26.5 ± 5.01 mmHg, respectively. The mean PP in the patients who underwent successful KP was 16.75 ± 3.54 mmHg while for those who continued to have jaundice it was 23.94 ± 4.63 mmHg (P < 0.001). NO levels closely followed the PP as shown by the regression equation NO = 4.79 + 0.64 PP mmHg, R² = 0.69. The mean NO level at presentation was 18.48 ± 4.17 μmol/L and at 1-month, 3-month, and 6-month follow-up was 11.94 ± 5.62 μmol/L, 10.79 ± 6.02 μmol/L, and 9.93 ± 6.53 μmol/L, respectively (P < 0.001). The difference in NO levels was also statistically significant between the patients who cleared jaundice and those with persisting jaundice.

Conclusion:

All BA patients had PHT at presentation. PHT worsens with age and has an adverse effect on outcome of KP. NO levels in blood closely follow PP and higher levels are associated with poor outcome.

Prediction of esophageal varices in biliary atresia: Derivation of the "varices prediction rule", a novel noninvasive predictor

BACKGROUND AND AIMS

Liver fibrosis and cirrhosis are nearly inevitable following Kasai portoenterostomy (KPE) for biliary atresia (BA), though the formation of varices is not. We sought to assess the value of noninvasive indices of portal hypertension (PHT), in predicting significant esophageal varices, and to develop a novel prediction model through regression modeling.

METHODS

This is a retrospective, observational study with analysis of routine biochemical and ultrasound data. Five indices were examined: AST-to-platelet ratio index (APRi); hepatic artery resistance index (HARI); spleen size z score (SSAZ); platelet count-to-SSAZ ratio (P/SSAZ); and clinical prediction rule (CPR) [(0.75 × platelets)/(SSAZ+5)]+(2.5 × albumin), each at specific time points following KPE (6 months, 1 year and 2 years). Significant varices were defined as grade ≥ 2 at endoscopy (screening or following a gastrointestinal bleed). AUROC was calculated for all indices. Univariate analysis was used to assess variables' suitability for inclusion in a subsequent multivariate logistic regression model to generate a predictive index. Data are quoted as median (range). P values ≤ 0.05 were regarded as significant.

RESULTS

195 infants (median age at KPE of 55 days [11-216]) were analyzed. 42 (22%) had significant varices (median time to first presentation of varices of 1.20 [0.20-6.40] years). CPR and APRi (AUROCs ranging from 0.73-0.80 and 0.69-0.83 respectively) performed best overall. Multiple logistic regression modeling yielded a novel predictor at 6 months post-KPE: the Varices Prediction Rule (albumin × platelets/1000) (AUROC 0.75, sensitivity 86%, sensitivity 71%).

CONCLUSIONS

Noninvasive indices such as CPR, APRi and now VPR can provide a tool for stratifying BA patients for elective endoscopy and possible preemptive intervention.

Long-term native liver fibrosis in biliary atresia: development of a novel scoring system using histology and standard liver tests

BACKGROUND & AIMS

Although liver fibrosis is an important predictor of outcomes for biliary atresia (BA), postsurgical native liver histology has not been well reported. Here, we retrospectively evaluated postsurgical native liver histology, and developed and assessed a novel scoring system - the BA liver fibrosis (BALF) score for non-invasively predicting liver fibrosis grades.

METHODS

We identified 259 native liver specimens from 91 BA patients. Of these, 180 specimens, obtained from 62 patients aged ≥1 year at examination, were used to develop the BALF scoring system. The BALF score equation was determined according to the prediction of histological fibrosis grades by multivariate ordered logistic regression analysis. The diagnostic powers of the BALF score and several non-invasive markers were assessed by area under the receiver operating characteristic curve (AUROC) analyses.

RESULTS

Natural logarithms of the serum total bilirubin, γ-glutamyltransferase, and albumin levels, and age were selected as significantly independent variables for the BALF score equation. The BALF score had a good diagnostic power (AUROCs=0.86-0.94, p<0.001) and good diagnostic accuracy (79.4-93.3%) for each fibrosis grade. The BALF score revealed a strong correlation with fibrosis grade (r=0.77, p<0.001), and was the preferable non-invasive marker for diagnosing fibrosis grades ⩾F2. In a serial liver histology subgroup analysis, 7/15 patients exhibited liver fibrosis improvement with BALF scores being equivalent to histological fibrosis grades of F0-1.

CONCLUSIONS

In postsurgical BA patients aged ⩾1year, the BALF score is a potential non-invasive marker of native liver fibrosis.

Aspartate Aminotransferase-to-Platelet ratio index (APRi) in infants with biliary atresia: prognostic value at presentation

BACKGROUND

Biliary atresia (BA) is a progressive obliterative cholangiopathy leading to liver fibrosis and cirrhosis. The aspartate aminotransferase-to-platelet ratio index (APRi) has been used in other liver diseases and in older children with BA as a surrogate marker of liver fibrosis. The aim of this study was to calculate APRi at time of presentation and relate this to operative findings and early outcome.

METHODS

Prospective single surgeon cohort study of infants with BA (January 1999-December 2010). Initial APRi values were related to other biochemical indices and liver appearance at the time of Kasai portoenterostomy. Data are expressed as median (interquartile range). Non-parametric comparison was performed and a P-value of≤0.05 was regarded as significant.

RESULTS

Overall 260 infants were included in the study. Median APRi was 0.67 (0.43-1.12) at a median age of surgery of 58 (range 14-209) days. APRi correlated with age (rs=0.44; P<0.0001), spleen size (rs=0.48; P<0.0001) and bilirubin (rs=0.45; P<0.0001). Liver assessment at operation was divided into cirrhosis [n=28 (10.8%)] or non-cirrhosis. Using a cut-off value of 1.22 [AUC 0.83 (95% CI 0.73-0.90)] showed a sensitivity of 75% and a specificity of 84% for macroscopic cirrhosis. Native liver survival was significantly different but improved only for those in the lowest APRi quartile (<0.43; P<0.009). APRi values at presentation had no significant association with later development of significant oesophageal varices.

CONCLUSION

APRi at the time of KP is a useful adjunct in evaluating severity of liver disease in BA at presentation.

Biliary atresia: clinical aspects

Biliary atresia (BA) remains an enigmatic disease with a degree of etiologic heterogeneity. A number of variants can be defined clinically, and these include the syndromic group (typically BA splenic malformation), cystic BA, and cytomegalovirus (CMV) IgM +ve associated BA. The remainder, and still the largest group, may be termed isolated BA(.) There is a wide variation in incidence across the globe from 1 in 5000 in Taiwan to 1 in 20,000 live births in Northern Europe, although the reasons for such a disparity remain obscure. Management remains primarily surgical with an attempt to restore bile flow by resection of extrahepatic biliary remnants and a reconstruction portoenterostomy (the Kasai procedure), reserving liver transplantation for those where this fails or complications of chronic liver disease supervene. Clearance of jaundice to normal values has been achieved in 40%-55% of cases in large series from around the world, with an expectation of 5-year native liver survival of similar proportions.