Procedure characteristics in Cohort 1, Cohort 2, in the non-elective subset and Overlapping Cohort
| Independent validation Cohort 1 (April 2004–March 2009) | Independent validation Cohort 2 (April 2015–July 2019) | Non-elective Cohort 2 subset (April 2015–July 2019) | Cohort Overlapping with PRAIS-2 cohort (April 2009–March 2015) | |
| Total number of procedures | 1352 | 1197 | 483 | 1824 |
| Age, year (median, IQR) | 6.3 (1.4–30.8) | 7.1 (2.2–51.0) | 1.7 (0.3–5.0) | 5.9 (1.3–38.6) |
| Weight, kg (median, IQR) | 6.1 (3.4–12.5) | 6.9 (3.9–15.5) | 3.7 (3.1–5.3) | 6.0 (3.6–13.4) |
| Diagnoses group, n (%)* | ||||
| GROUP 1 | 71 (5.3) | 107 (8.9) | 47 (9.7) | 154 (8.4) |
| GROUP 2 | 149 (11.0) | 163 (13.6) | 77 (15.9) | 194 (10.6) |
| GROUP 3 | 111 (8.2) | 103 (8.6) | 65 (13.5) | 125 (6.9) |
| GROUP 4 | 218 (16.1) | 232 (19.4) | 118 (24.4) | 222 (12.2) |
| GROUP 5 | 104 (7.7) | 122 (10.2) | 49 (10.1) | 123 (6.7) |
| GROUP 6 | 104 (7.7) | 137 (11.4) | 45 (9.3) | 100 (5.5) |
| GROUP 7 | 176 (13.0) | 127 (10.6) | 34 (7.0) | 312 (17.1) |
| GROUP 8 | 155 (11.5) | 105 (8.8) | 32 (6.6) | 192 (10.5) |
| GROUP 9 | 20 (1.5) | <5 (<1) | <5 (<1) | 25 (1.4) |
| GROUP 10 | 56 (4.1) | 14 (1.2) | 6 (1.2) | 95 (5.2) |
| GROUP 11 | 188 (13.9) | 85 (7.1) | 8 (1.7) | 282 (15.5) |
| Procedure group, n (%)* | ||||
| GROUP 1 | <5 (<1) | 31 (2.6) | 22 (4.6) | 28 (1.5) |
| GROUP 2 | 29 (2.1) | 11 (0.9) | 10 (2.1) | 33 (1.8) |
| GROUP 3 | 107 (7.9) | 46 (3.8) | 34 (7.0) | 84 (4.6) |
| GROUP 4 | 99 (7.3) | 103 (8.6) | 73 (15.1) | 114 (6.2) |
| GROUP 5 | 239 (17.7) | 228 (19.0) | 126 (26.1) | 344 (18.9) |
| GROUP 6 | 148 (10.9) | 53 (4.4) | 36 (7.5) | 180 (9.9) |
| GROUP 7 | 21 (1.6) | 45 (3.8) | 17 (3.5) | 50 (2.7) |
| GROUP 8 | 86 (6.4) | 100 (8.4) | 12 (2.5) | 126 (6.9) |
| GROUP 9 | 20 (1.5) | 16 (1.3) | 5 (1.0) | 26 (1.4) |
| GROUP 10 | 36 (2.7) | 35 (2.9) | 7 (1.4) | 70 (3.8) |
| GROUP 11 | 36 (2.7) | 19 (1.6) | 8 (1.7) | 57 (3.1) |
| GROUP 12 | 32 (2.4) | 64 (5.3) | 1 (0.2) | 50 (2.7) |
| GROUP 13 | 87 (6.4) | 68 (5.7) | 5 (1.0) | 103 (5.6) |
| GROUP 14 | 38 (2.8) | 43 (3.6) | 7 (1.4) | 55 (3.0) |
| GROUP 15 | 217 (16.1) | 144 (12.0) | 11 (2.3) | 275 (15.1) |
| GROUP 20 | 156 (11.5) | 191 (16.0) | 109 (22.6) | 229 (12.6) |
| Bypass n (%) | 903 (66.8) | 911 (76.1) | 273 (56.5) | 1361 (74.6) |
| Univentricular heart category, n (%) | 143 (10.6) | 219 (18.3) | 95 (19.7) | 258 (14.1) |
| Severity of illness†, n (%) | 0 (0.0) | 222 (18.5) | 203 (42.0) | 86 (4.7) |
| Acquired comorbidity†, n (%) | 9 (0.7) | 207 (17.3) | 132 (27.3) | 94 (5.2) |
| Additional cardiac risk factors†, n (%) | 58 (4.3) | 82 (6.9) | 56 (11.6) | 52 (2.9) |
| Congenital comorbidity†, n (%) | 173 (12.8) | 343 (28.7) | 143 (29.6) | 274 (15.0) |
| PRAIS-2 (median, IQR) | 0.0115 (0.0037–0.0258) | 0.010 (0.004–0.027) | 0.029 (0.011–0.068) | 0.011 (0.003–0.027) |
| 30-day mortality, n (%) | 32 (2.4) | 23 (1.9) | 22 (4.6) | 56 (3.1) |
*As the diagnoses groups and procedure groups have lengthy text details, we have not provided them in the table; they can be found in online supplemental table 5.
†Exact number suppressed for disclosure control purposes.
‡Definitions of variables are given in online supplemental table 5.