Table 1.
Patient Characteristics and Outcomes by Acute Kidney Injury (AKI) Definition Methods in 287 Children Undergoing Cardiac Surgery
| Variable | No AKI by SCr or CysC (n = 154) |
SCr-AKI Only (n = 74) |
CysC-AKI Only (n = 8) |
AKI by SCr and CysC (n = 51) |
|---|---|---|---|---|
| Patient Characteristics | ||||
| Age, mean (SD), y | 4.8 (4.7) | 3.0 (4.1) | 5.4 (5.1) | 1.9 (3.8)a |
| Male sex, No. (%) | 88 (57.1) | 46 (62.2) | 6 (75.0) | 19 (37.3)a,b |
| Nonwhite race, No. (%) | 27 (17.5) | 10 (13.5) | 1 (12.5) | 15 (29.4) |
| Preoperative SCr-estimated GFR, mean (SD), mL/min/1.73 m2 | 90.3 (20.7) | 104.3 (28.3) | 79.2 (15.6) | 73.0 (23.0)a,b |
| Abnormal preoperative GFR, No. (%)c | 46 (29.9) | 6 (8.1) | 4 (50.0) | 17 (33.3)a,b |
| Preoperative CysC, median (25th-75th percentiles), mg/L | 0.71 (0.61–0.86) | 0.81 (0.66–0.96) | 0.59 (0.44–0.65) | 0.84 (0.66–1.17)a |
| Prior cardiac surgery, No. (%) | 57 (37.0) | 36 (48.6) | 5 (62.5) | 17 (33.3) |
| Elective surgery, vs urgent, No. (%) | 143 (92.9) | 71 (95.9) | 7 (87.5) | 45 (88.2) |
| Preoperative medication, No. (%) | ||||
| Loop diuretic | 34 (22.1) | 27 (36.5) | 2 (25.0) | 23 (45.1) |
| Angiotensin-converting enzyme inhibitor | 22 (14.3) | 17 (23.0) | 3 (37.5) | 8 (15.7) |
| Risk Adjustment in Congenital Heart Surgery 1 category, No. (%)d | (n = 153) | (n = 73) | ||
| 1 | 17 (11.1) | 0 | 0 | 0 |
| 2 | 76 (49.7) | 35 (47.9) | 4 (50.0) | 24 (47.1) |
| 3 | 58 (37.9) | 34 (46.6) | 4 (50.0) | 21 (41.2) |
| 4 | 2 (1.3) | 4 (5.5) | 0 | 6 (11.8)a |
| Cardiopulmonary bypass time, mean (SD), min | 88.9 (47.6) | 114.7 (67.4) | 111.5 (54.4) | 149.5 (77.9)a,b |
| Aortic cross-clamp time, mean (SD), min | 42.1 (39.3) | 44.8 (48.6) | 53.1 (74.5) | 69.9 (51.3)a,b |
| Site, No. (%) | ||||
| Cincinnati, Ohio | 113 (73.4) | 41 (55.4) | 6 (75.0) | 37 (72.5) |
| Montreal, Quebec, Canada | 27 (17.5) | 18 (24.3) | 2 (25.0) | 9 (17.6) |
| New Haven, Connecticut | 14 (9.1) | 15 (20.3) | 0 | 5 (9.8) |
| Outcomes | ||||
| SCr-AKI, No. (%) | ||||
| No AKI | 154 (100) | 0 | 8 (100) | 0 |
| Stage 1 | 0 | 65 (87.8) | 0 | 16 (31.4) |
| Stage 2 | 0 | 8 (10.8) | 0 | 3 (5.9) |
| Stage 3 | 0 | 1 (1.4) | 0 | 32 (62.7) |
| In-hospital death | 0 | 2 (2.7) | 0 | 2 (3.9) |
| Length, median (IQR), d | ||||
| ICU stay | 2 (1–3) | 3 (2–5) | 3 (2–3) | 4 (3–7)a,e |
| Hospital stay | 4 (3–6) | 6 (4–10) | 5 (6–7) | 8 (6–15)a,e |
| Mechanical ventilation | 1 (0–1) | 1 (1–3) | 1 (0–1) | 2 (1–4)a,e |
Abbreviations: CysC, cystatin C; CysC-AKI, CysC-defined AKI; GFR, glomerular filtration rate; ICU, intensive care unit; IQR, interquartile range; SCr, serum creatinine; SCr-AKI, SCr-defined AKI.
Statistically significant difference across the 4 groups (P < .05, analysis of variance).
Statistically significant difference between SCr-AKI only group vs AKI by SCr and CysC group (P < .005, correction for multiple comparisons).
Defined as less than 90 mL/min/1.73 m2 if at least 2 years old, less than 76 if 1.5 to younger than 2 years, less than 74 if 1 to younger than 1.5 years, less than 65 if 8 months to younger than 1 year, and less than 58 if 3 to younger than 8 months.30
It was not possible to categorize this in 2 individuals (one in column 1 and another in column 2). Therefore, the group frequencies do not add up to column totals.
Longer in AKI by SCr and CysC group vs SCr-AKI only group (P = .05).