Characteristic | Aged 1 mo–2 yr | Aged ≥2 yr | ||||
---|---|---|---|---|---|---|

ACR <30 mg/g (n=33)^{a} | ACR 30–<300 mg/g (n=67) | ACR ≥300 mg/g (n=14) | ACR <10 mg/g (n=50) | ACR 10–<30 mg/g (n=55) | ACR ≥30 mg/g (n=36) | |

Age at surgery (yr)^{b} | 0.69±0.45 | 0.50±0.35 | 0.49±0.38^{c} | 7.4±3.8 | 6.8±4.4 | 6.9±4.7 |

Male sex | 18 (55) | 42 (63) | 6 (43) | 28 (56) | 25 (45) | 24 (67) |

White race^{b} | 31 (94) | 53 (79) | 12 (86) | 37 (74) | 51 (93) | 27 (75) |

Study site | ||||||

Cincinnati | 27 (82) | 39 (58) | 10 (71)^{c} | 35 (70) | 33 (60) | 24 (67) |

Montreal | 5 (15) | 18 (27) | 0 (0) | 13 (26) | 14 (25) | 7 (19) |

Yale | 1 (3) | 10 (15) | 4 (29) | 2 (4) | 8 (15) | 5 (14) |

Preoperative eGFR^{d} | 87.2±26.4 | 78.7±24.3 | 82.4±28.5 | 96.9±20.6 | 102.0±20.1 | 103.6±26.5 |

Preoperative eGFR percentile^{d} | 66.2±33.4 | 59.2±34.9 | 67.5±30.8 | 39.2±31.2 | 46.9±31.0 | 45.8±34.8 |

RACHS-1 score | 2.4±0.7 | 2.5±0.7 | 2.3±0.5 | 2.2±0.7 | 2.5±0.7 | 2.6±0.7^{d} |

CPB time (min) | 114±82 | 113±51 | 102±46 | 94±55 | 108±73 | 118±73 |

Cross-clamp time (min) | 61±46 | 65±44 | 51±40 | 34±37 | 36±49 | 44±51 |

Outcomes | ||||||

Stage 1 or higher AKI | 19 (58) | 34 (51) | 8 (57) | 12 (24) | 17 (31) | 14 (39) |

Stage 2 or 3 AKI | 10 (30) | 15 (22) | 2 (14) | 3 (6) | 7 (13) | 6 (17) |

ICU stay (d) | 3 (2–5) | 3 (2–6) | 3 (2–13) | 1 (1–2) | 2 (1–4) | 2 (1–4)^{e} |

Hospital stay (d) | 6 (4–9.5) | 6 (5–12) | 6 (4–19) | 4 (3–5) | 5 (3–7) | 5.5 (3–9.5)^{c} |

Dialysis | 0 (0) | 1 (1) | 0 (0) | 0 (0) | 1 (2) | 2 (6) |

Mortality | 0 (0) | 0 (0) | 0 (0) | 2 (4) | 0 (0) | 2 (6) |

Data are mean ± SD,

*n*(%), or median (interquartile range). ACR, albumin/creatinine ratio; eGFR, estimated GFR; RACHS-1, risk adjustment for congenital heart surgery; CPB, cardiopulmonary bypass; ICU, intensive care unit.↵a ACR cutoffs evaluated differed for the two age groups based on the known association of higher ACR in children aged <2 years. To convert to SI units (mg albumin per mmol creatinine), divide ACR by 8.84.

↵b Interval variables presented as mean ± SD and categorical variables presented as

*n*(% of column total).↵c Denotes a statistically significant difference between the three ACR categories with

*P*<0.05.↵d GFR was estimated using the Schwartz equation (18); eGFR percentile was calculated using normative-based values from a previous study (8).

↵e Denotes a statistically significant difference between the three ACR categories with

*P*<0.01.