Biliary Atresia and Bile Lakes

A retrospective study (DA Ginström et al. JPGN 2019; 488-94) review cholangitis associated with biliary atresia and the role of bile leaks.  This study encompasses a ~30 year period (1987-2016) and 61 patients.

Key findings: 

  • 54% had survived with their native liver at a median of 7.3 years; 28 (46%) had ≥ 1 cholangitis episodes/year
  • Cholangitis bouts were >5 times higher among patients with bile lakes
  • Management of bile lakes after 1995 (n=6) was with operative intestinal drainage (bile-lake jejunostomy) which resulted in disappearance or regression of bile lakes in all patients.  Associated with this, yearly cholangitis bouts decreased from 8.8 (4.2-14) to 1.1 (0.2-3.2). Prior to 1995, two patients were managed with PTCD; both died within one year.
  • Among patients who had surgical drainage of their bile lakes, 4 have survived jaundice-free and 2 received liver transplants at 1.3 and 4.9 years after intestinal drainage.

My take: This report provides insight into the management of bile lakes (also referred to as intrahepatic biliary cysts) indicating that bile-lake jejunostomy is effective in symptomatic patients.

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Blood Test is Better Than a Liver Biopsy for Biliary Atresia

A recent study (L Yang et al. Hepatology 2018; 68: 2069-72) confirms the utility of Serum Matrix Metalloproteinase-7 (MMP-7) as a biomarker for biliary atresia (BA). The authors studied MMP-7 among healthy controls (n=72 with 54 <6 months) and among 135 with cholestasis (75 with BA, 60 with non-BA).  BA samples were taken at a median age of 54 days.

Key findings:

  • Median concentration for MMP-7 was 2.86 ng/mL in healthy controls, 11.47 ng/mL for non-BA cholestasis, and 121.1 ng/mL for BA.
  • Using a cutoff value of 52.85 ng/mL, the diagnostic sensitivity and specificity were 98.67% and 95.0% respectively.
  • The AUC for MMP-7 in BA was 0.99 compared for AUC for GGT of 0.72.  The sensitivity and specificity for GGT was much lower at 64% and 72% respectively with a cutoff of 314 U/L.
  • The predictive value for MMP-7 was particularly impressive, 74 of 75 BA  subjects were correctly identified as having BA.  Only 3 non-BA patients were incorrectly assigned a BA diagnosis based on MMP-7 values.
  • The authors noted that MMP-7 testing indicates that there are no substantial changes in its values for normal subjects extending to 54 years of age.
  • One limitation the authors note is the relatively small number of patients with non-BA syndromatic intrahepatic cholestasis which made up less than 30% of their non-BA cohort.  Thus, more testing in specific populations is needed.

My take: The diagnostic performance of MMP-7** appears to be superior to that of a liver biopsy (though this was not directly compared in this study) in predicting BA and could obviate the need for most liver biopsies in infants with cholestasis.  Those with high MMP-7 values would proceed directly to intraoperative cholangiogram with possible hepatoportojejunostomy. Those with non-BA MMP-7 values and persistent cholestasis could undergo additional investigation with genetic panels and/or other metabolic/infectious testing.

**This assay is likely to be commercially-available in the coming weeks according to a colleague at Cincnnati Children’s Hospital.  The expectation is an approximagely 2-day turnaround.

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Bilary Atresia Prognosis After 2-Year Survival with Native Liver

A recent study (M Witt et al. JPGN 2018; 689-94) indicates that among patients with biliary atresia who reached 2 years of life with native liver survival (NLS), they continued to be at risk for progressive liver failure.

Key findings:

  • Upon a median follow-up of 16.4 years, NLS rates at 5, 10, 15, 18 years of age were 89%, 72%, 60%, 54%, respectively.
  • Corresponding overall survival rates were 98%, 90%, 87%, 87%, respectively
  • NLS ended in 37% by liver transplantation (LTx) and in 6% by (pre-transplant) mortality.
  • Abstract Link: Prognosis of Biliary Atresia After 2-year Survival With Native Liver

My take: This data provides more precise information for families about prognosis and reinforces the need for careful followup.

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Liver Shorts November 2018

J Ge et al. Hepatology 2018; 68: 1101-10.  This study reviewed liver donation offers between 2010 to 2014.  This study found that 5.6% of men (293/5202) and 6.2% of women (179/2899) received a pediatric donor as a first offer.  Women, but not men, who received a pediatric first offer had a lower risk of waitlist mortality than with those who received adult organ offers. The authors recommend that “offers of pediatric donor liver be prioritized to women, who are generally shorter stature, once alllocation to the entire…pediatric waitlist pool has occurred.”

CA Chapin et al. Hepatology 2018; 68: 1087-1100.  This study found that patients with indeterminate pediatric acute liver failure (iPALF) have a unique pattern of dense CD8+ T-cell infiltrate that is also perforin-positive adn CD103-positive.  These CD8+ cells are a biomarker for immune dysregulation. These CD8+ dense pattern was found in the 27 of 33 patients with iPALF; 3 had moderate and 3 had minimal staining pattern (per table 2).  The dense CD8+ pattern was seen in 3 of 9 with autoimmune hepatitis and in 1 of 14 with other liver diseases.

E-D Pfister et al. Liver Transplantation 2018; 24: 1186-98.  This study examined patient (n=338) and graft survival in the pediatric population (median age 14.0 years) with Wilson’s disease (1968-2013).  Overall, patient survival was 87% at 1 year, 84% at 5 years, and 81% at 10 years.  Though, the survival was much improved since 2009.

JA Bezzerra et al. Hepatology 2018; 68: 1163-73. This review summarized a research workshop (June 2017) focused on the clinical and research challenges for biliary atresia.

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How Often Is Surgical Treatment for Biliary Atresia Delayed Beyond 60 Days?

It is recognized that there is often a delay in the diagnosis of biliary atresia (BA).  A recent study (MR Townsend et al. J Pediatr 2018; 199: 237-42) indicates that hepatoportoenterostomy (HPE) or Kasai procedure is performed in only 37.7% of patients with BA prior to 60 days of age. The data was obtained from the Agency for Healthcare Research and Quality’s Healthcare Cost and Utilization Project (HCUP) Nationwide Inpatient Sample files from 2000-2011.

  • Risk factors for delayed HPE: This study of 1243 patients with BA found that those with delayed HPE were more often uninsured–all self-pay patients had HPE after 60 days, more often black (aOR 4.22), and less likely at a teaching hospital (aOR 0.27).
  • Delayed HPE was associated with increased adverse perioperative outcomes and increased cost.

My take: We have a long way to go if we are going to consistently identify and treat BA in a timely manner.

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Time-to-diagnosis of Biliary Atresia

A recent study (S Harpavat et al. JPGN 2018; 66: 850-6) identifies race/ethnicity as a factor affecting the timeliness of diagnosis.

Specifically, non-Hispanic white infants were diagnosed earlier than non-Hispanic black infants and Hispanic infants (P=.007); this was related to the timing of referral from the primary care physician.  The authors speculate that this could be related to three factors:

  • lighter colored skin could help identify jaundice more quickly
  • better access to health care
  • implicit bias leading to uneven treatment

The other finding in the study was that after referral, patients referred after 30 days of life had a more expedited diagnosis than those referred prior to 30 days of life.  The authors caution that the histology in these early cases is similar to those who present later, even if their aminotransferases are normal.  In addition, while physicians and parents want to avoid ‘over testing,’ prompt diagnosis, even prior to 30 days of life, may lead to improved outcomes.  Thus, the authors recommend proceeding with liver biopsy if there is clinical suspicion of biliary atresia.

My take: Obtaining objective evidence of cholestasis in infants that are jaundiced beyond 2 weeks of life is important.  This study highlights some of the reasons why the diagnosis is delayed in so many.

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Will We Still Need Liver Biopsies to Diagnose Biliary Atresia in a Few Years?

A recent study (C Lertudomphonwanit, R Moura, L Fei, Y Zhang, S Gutta, L Yang, KE Bove, P Shivakumar, JA Bezerra. Sci Transl Med. 2017; 9: eaan8462) may change how we diagnose biliary atresia (BA) and provides an insight into potential pathogenesis. Link to studyLarge-scale proteomics identifies MMP-7 as a sentinel of epithelial injury and of biliary atresia

Using large-scale proteomics, the authors screened 1129 proteins in a discovery cohort (n=70) of patients with BA.  They identified several proteins that were increased with BA. Matrix metalloproteinase-7 (MMP-7) was the lead biomarker.  Subsequently, they used two additional validation cohorts.  Human subjects were infants in enrolled in the Prospective Database of Infants with Cholestasis (PROBE) which is part of the NIDDK-funded ChiLDRen (www.childrennetwork.org).

Key findings:

  • 76 proteins were significantly overexpressed or underexpressed in BA compared with children with intrahepatic cholestasis (IHC).
  • MMP-7 was more accurate than gamma glutamyltranspeptidase (GGT).  The combination of MMP-7 and GGT had a AUROC of 0.94 in validation cohorts.
  • The authors further studied the role of MMP-7 by immunostaining and found it primarily was detected in cholangiocytes of intrahepatic bile ducts in infants with BA.  It was also identified in a few hematopoietic cells.
  • MMP-7 expression in the liver did not correlate with fibrosis.
  • MMP-7 serum levels increased in neonatal mice after bile duct epithelial injury induced by intraperitoneal rotavirus administration.
  • Using a mice model, they found that a MMP-7 inhibitor (batimastat) could block the development of BA in a mouse model (in 86% of cases) compared with 0% in control mice.
  • Overall, the authors note that coupled with GGT, MMP-7 serum levels result in “sensitivity and specificity of 97 and 94% respectively, at optimal cutoff, which provided positive and negative predictive values of 85 and 99% respectively, if one considers the prevalence of BA of 25.9% among infants with conjugated hyperbilirubinemia.”

My take: More work is needed.  However, these values suggest that MMP-7 and GGT combined may be more accurate than a liver biopsy in the diagnosis of BA.

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