Biliary atresia with associated structural malformations in Canadian infants

Background: Biliary atresia (BA) is associated with extrahepatic congenital malformations in a minority of affected infants. The term commonly applied to this subgroup is ‘BASM’ for biliary atresia splenic malformation syndrome, as spleen abnormalities are prominent. Aims and methods: To examine clinical outcome in Canadian BA patients with extrahepatic congenital malformations in the Canada‐wide BA database of patients born between 1985 and 2002, and additionally, to recharacterized the syndrome. Patients had ≥1 of the following: a/polysplenia, abnormal abdominal situs, intestinal malrotation, abdominal vascular anomaly or congenital heart disease. Results: Among 328 BA patients, 44 (13%) had associated congenital abnormalities. Intra‐abdominal anomalies included polysplenia (n=25), abnormal abdominal situs (n=9), intestinal malrotation (n=19), portal vein anomaly (n=12), hepatic artery anomaly (n=3) and inferior vena cava interruption (n=20). Twenty‐six patients had cardiac malformations including pulmonary stenosis (n=11), ventricular septal defect (n=10), atrial septal defect (n=7), total anomalous pulmonary venous return (n=3), double outlet right ventricle (n=3), tetralogy of Fallot (n=2), atrioventricular canal (n=2), dextrocardia (n=2), bicuspid aortic valve (n=2), hypoplastic left heart (n=1) and partial anomalous pulmonary venous return (n=1). Age at Kasai operation, performance of liver transplant, overall survival, post‐Kasai native liver survival and transplant survival were comparable to isolated BA. Presence of polysplenia or complex cardiac disease did not reduce post‐Kasai native liver survival. Three patients had ≥2 typical abnormalities without polysplenia: thus, splenic malformations are not essential to this BA subgroup. Hierarchical cluster analysis demonstrated characteristic abnormalities grouped in a multiplicity of combinations, consistent with a spectrum of defective lateralization. Conclusion: We suggest that the acronym ‘BASM’ be redefined as ‘biliary atresia structural malformation’.