Table 2 Clinical characteristics of the study population in the training and testing groups
Parameters | All (n = 1003) | Training group(n = 703) | Testing group(n = 300) | P |
|---|---|---|---|---|
General characteristics | ||||
 AKI (%): No | 675 (67.3) | 474 (67.4) | 201 (67.0) | 0.895 |
 Yes | 328 (32.7) | 229 (32.6) | 99 (33.0) |  |
 Age,y | 52.57 ± 13.35 | 52.70 ± 13.30 | 52.27 ± 13.48 | 0.645 |
 Gender (%):Male | 580 (57.8) | 403 (57.3) | 177 (59.0) | 0.623 |
 Female | 423 (42.2) | 300 (42.7) | 123 (41.0) |  |
 BMI,Kg/m2 | 22.99 ± 3.56 | 22.85 ± 3.49 | 23.30 ± 3.71 | 0.071 |
ASA,grade(%) | ||||
 2 | 21 (2.1) | 13 (1.8) | 8 (2.7) | 0.490 |
 3 | 778 (77.6) | 542 (77.1) | 236 (78.7) |  |
 4 | 201 (20.0) | 145 (20.6) | 56 (18.7) |  |
 5 | 3 (0.3) | 3 (0.4) | 0 (0.0) |  |
 Smoke (%) | 291 (29.0) | 204 (29.0) | 87 (29.0) | 0.995 |
 Drink (%) | 125 (12.5) | 90 (12.8) | 35 (11.7) | 0.618 |
Preoperative complications | ||||
 Stroke (%) | 62 (6.2) | 47 (6.7) | 15 (5.0) |  |
 Hypertension (%) | 265 (26.4) | 186 (26.5) | 79 (26.3) | 0.967 |
 Diabetes (%) | 99 (9.9) | 73 (10.4) | 26 (8.7) | 0.295 |
 Diabetes without treatment | 25 (2.5) | 19 (2.7) | 6 (2.0) | 0.513 |
 Diabetes treated with oral meditations | 54 (5.4) | 43 (6.1) | 11 (3.7) | 0.115 |
 Insulin-dependent diabetes | 20 (2.0) | 11 (1.6) | 9 (3.0) | 0.137 |
 Atrial fibrillation (%) | 196 (19.5) | 137 (19.5) | 59 (19.7) | 0.948 |
 After PCI or Heart attack(%) | 69 (6.9) | 45 (6.4) | 24 (8.0) | 0.360 |
 COPD (%) | 36 (3.6) | 24 (3.4) | 12 (4.0) | 0.648 |
 PH (%) | 340 (33.9) | 238 (33.9) | 102 (34.0) | 0.965 |
 Previous cardiac surgery (%) | 76 (7.6) | 50 (7.1) | 26 (8.7) | 0.394 |
 Cardiogenic shock (%) | 2 (0.2) | 2 (0.3) | 0 (0.0) | 0.355 |
 Intra-aortic balloon pump (%) | 2 (0.2) | 1 (0.1) | 1 (0.3) | 0.535 |
 NYHA III or IV (%) | 204 (20.3) | 148 (21.1) | 56 (18.7) | 0.390 |
Laboratory measurements | ||||
 LVEF,% | 64.21 ± 10.16 | 64.31 ± 9.98 | 63.98 ± 10.59 | 0.636 |
 WBC, × 109/L | 6.96 ± 2.19 | 7.03 ± 2.18 | 6.78 ± 2.22 | 0.087 |
 RBC, × 1012/L | 4.57 ± 0.70 | 4.56 ± 0.70 | 4.61 ± 0.70 | 0.280 |
 Hb,g/L | 131.93 ± 20.23 | 131.33 ± 19.94 | 133.35 ± 20.85 | 0.148 |
 HCT,% | 0.40 ± 0.06 | 0.40 ± 0.06 | 0.40 ± 0.06 | 0.229 |
 Plt, × 109/L | 220.67 ± 68.08 | 221.52 ± 68.00 | 218.66 ± 68.34 | 0.542 |
 ALT,U/L | 20 [14, 29] | 20 [14, 29] | 20 [14, 29] | 0.849 |
 AST,U/L | 23 [19, 29] | 23 [19, 29] | 22 [19, 30] | 0.807 |
 TBIL,umol/L | 13.8 [10.10, 19.25] | 13.8 [10.25, 19.15] | 14.25 [10.00, 19.72] | 0.586 |
 ALB,g/L | 38.78 ± 4.01 | 39.14 ± 3.76 | 38.63 ± 4.10 | 0.066 |
 BUN,μmol/L | 6.05 ± 2.28 | 6.04 ± 2.31 | 6.07 ± 2.21 | 0.837 |
 Scr,μmol/L | 79.33 ± 18.77 | 78.89 ± 18.65 | 80.36 ± 19.05 | 0.258 |
 eGFR | 80.88 ± 30.77 | 80.71 ± 31.57 | 81.28 ± 28.88 | 0.787 |
 UA,μmol/L | 399.28 ± 121.79 | 393.66 ± 121.21 | 412.45 ± 122.35 | 0.025 |
 INR | 1.05 [0.99, 1.14] | 1.05 [0.99, 1.15] | 1.05 [0.98, 1.14] | 0.932 |
 NT-proBNP,ng/L | 348.8 [104.25, 1126.50] | 374.1 [108.65, 1189.50] | 326.6 [88.45, 1088.75] | 0.435 |
Intra-operative characteristics | ||||
 Surgical time,min | 368.63 ± 126.52 | 365.80 ± 125.05 | 375.29 ± 129.84 | 0.277 |
 CPB time,min | 167.36 ± 82.53 | 166.20 ± 82.19 | 170.09 ± 83.39 | 0.495 |
 Aortic occlusion time,min | 95.98 ± 51.71 | 95.38 ± 50.93 | 97.38 ± 53.56 | 0.574 |
 Intra-operative defibrillation (%) | 239 (23.8) | 159 (22.6) | 80 (26.7) | 0.168 |
 Minimum temperature,℃ | 34.6 [34.10, 34.90] | 34.7 [34.10, 34.90] | 34.6 [34.10, 34.90] | 0.232 |
Intra-operative medications | ||||
 Dexmedetomidine (%) | 599 (59.7) | 432 (61.5) | 167 ( 55.7) | 0.087 |
 Dopamine (%) | 152 (15.2) | 104 (14.8) | 48 ( 16.0) | 0.626 |
 Dobutamine (%) | 624 (62.2) | 447 (63.6) | 177 (59.0) | 0.170 |
 Norepinephrine (%) | 845 (84.2) | 596 (84.8) | 249 (83.0) | 0.479 |
 Adrenaline (%) | 154 (15.4) | 113 (16.1) | 41 (13.7) | 0.333 |
Intra-operative inflow and outflow | ||||
 Blood loss,ml | 500 [400, 600] | 500 [400, 600] | 500[400, 600] | 0.822 |
 Urine,ml | 1475.14 ± 854.58 | 1484.19 ± 872.89 | 1453.93 ± 811.09 | 0.608 |
 Crystalloid,ml | 1627.99 ± 558.99 | 1622.25 ± 568.46 | 1641.43 ± 536.84 | 0.619 |
 Voluven,ml | 0 [0.0, 0.0] | 0 [0.0, 0.0] | 0 [0.0, 0.0] | 0.606 |
 Gelofusine,ml | 0 [0.0, 500] | 0 [0.0, 500] | 0 [0.0, 500] | 0.661 |
 RBC transfusion,ml | 260 [0.0, 490] | 260 [0.0, 520] | 345 [0.0, 460] | 0.963 |
 FFP transfusion,ml | 400 [200, 600] | 400.00 [200, 600] | 400 [300, 600] | 0.059 |
 Cryoprecipitate transfusion,ml | 0 [0.0, 0.0] | 0 [0.0, 0.0] | 0 [0.0, 0.0] | 0.358 |
 ALB transfusion,ml | 0 [0.0, 0.0] | 0 [0.0, 0.0] | 0 [0.0, 0.0] | 0.319 |
 PLT transfusion,ml | 0 [0.0, 1.0] | 0.0 [0.0, 1.0] | 0 [0.0, 1.0] | 0.469 |
 Total infusion,ml | 5316.68 ± 2139.67 | 5261.26 ± 2170.86 | 5446.55 ± 2062.46 | 0.209 |
Surgery | ||||
 Valve surgery (%) | 611 (60.9) | 435 (61.9) | 176 (58.7) | 0.340 |
 CABG (%) | 127 (12.7) | 91 (12.9) | 36 (12.0) | 0.680 |
 Valve surgery combined with CABG (%) | 39 (3.9) | 27 (3.8) | 12 (4.0) | 0.905 |
 Vascular surgery (%) | 74 (7.4) | 47 (6.7) | 27 (9.0) | 0.199 |
 Congenital heart surgery (%) | 87 (8.7) | 52 (7.4) | 35 (11.7) | 0.031 |
 Heart transplant surgery (%) | 2 (0.2) | 2 (0.3) | 0 (0.0) | 0.355 |
 Other cardiac surgeries (%) | 63 (6.3) | 47 (6.7) | 16 (5.3) | 0.419 |
 Emergent surgery(%) | 14 (1.4) | 10 (1.4) | 4 (1.3) | 0.912 |
Indicator after surgery | ||||
 Postoperative PCT on day 1,ng/ml | 3.24 ± 8.48 | 2.85 ± 6.91 | 4.16 ± 11.30 | 0.025 |