Table 1.

Patient characteristics by age group and by preoperative ACR category

CharacteristicAged 1 mo–2 yrAged ≥2 yr
ACR <30 mg/g (n=33)aACR 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)b0.69±0.450.50±0.350.49±0.38c7.4±3.86.8±4.46.9±4.7
Male sex18 (55)42 (63)6 (43)28 (56)25 (45)24 (67)
White raceb31 (94)53 (79)12 (86)37 (74)51 (93)27 (75)
Study site
 Cincinnati27 (82)39 (58)10 (71)c35 (70)33 (60)24 (67)
 Montreal5 (15)18 (27)0 (0)13 (26)14 (25)7 (19)
 Yale1 (3)10 (15)4 (29)2 (4)8 (15)5 (14)
Preoperative eGFRd87.2±26.478.7±24.382.4±28.596.9±20.6102.0±20.1103.6±26.5
Preoperative eGFR percentiled66.2±33.459.2±34.967.5±30.839.2±31.246.9±31.045.8±34.8
RACHS-1 score2.4±0.72.5±0.72.3±0.52.2±0.72.5±0.72.6±0.7d
CPB time (min)114±82113±51102±4694±55108±73118±73
Cross-clamp time (min)61±4665±4451±4034±3736±4944±51
Outcomes
 Stage 1 or higher AKI19 (58)34 (51)8 (57)12 (24)17 (31)14 (39)
 Stage 2 or 3 AKI10 (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
 Dialysis0 (0)1 (1)0 (0)0 (0)1 (2)2 (6)
 Mortality0 (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.