ObjectivesTo describe the range of concurrent cardiac malformations in biliary atresia (BA) while providing a functional framework of risk.MethodsDemographic and variables were collected from a prospectively maintained single-centre database. Infants were grouped according to a cardiac functional framework (A=acyanotic, B=cyanotic and C=insignificant shunt). Primary outcome was set as clearance of jaundice (bilirubin ≤20 μmol/L) following Kasai portoenterostomy (KPE). Native liver survival and overall actuarial survival were compared with a date-matched control infant with BA (n=77). P value <0.05 was regarded as significant.Results524 infants with histologically confirmed BA were treated between January 1999 and December 2018, 37 (7%) had a concurrent cardiac anomaly (A: n=23 (62%), B: n=10 (27%), C: n=4 (11%)). Infants with biliary atresia splenic malformation (BASM) or cat-eye syndrome (CES) contributed over half of the cases (21/37; 57%).Overall, 20 (54%) infants cleared jaundice (vs 50/77 (65%) controls; p=0.2), but with higher mortality compared with the non-cardiac controls (15/37 (40%) vs 3/77 (4%); HR 15.5 (95% CI 5.5 to 43.4); p<0.00001). Infants requiring cardiac intervention in the first year of life (n=15) were more likely to clear jaundice (6/7 vs 2/8; p=0.04) and had a trend towards higher survival (6/7 vs 3/8; p=0.1) when KPE followed cardiac surgery. Yet, the type of cardiac pathology did not impact clearance of jaundice or mortality.ConclusionWe propose the term cardiac-associated biliary atresia (CABA) as a high-risk group. We believe that restorative cardiac surgery should precede KPE wherever possible to improve outcome.