Table 1.
Clinical Characteristics of Derivation and Validation Cohort
| Derivation Cohort (N=6081) | Validation Cohort (N=1152) | |
|---|---|---|
| Preoperative | ||
| Male | 3767 (61.9%) | 725 (62.9%) |
| Age, y | 58 (48, 65) | 60 (52, 66) |
| Renal function | ||
| Serum creatinine, μmol/L | 77 (65, 89) | 78 (66, 90) |
| eGFR, mL/min per 1.73 m2 | 88.7 (69.7, 99.6) | 86.5 (67.6, 101.6) |
| Comorbidities | ||
| Hypertension | 2012 (33.1%) | 403 (34.9%) |
| DM | 763 (12.5%) | 200 (17.4%) |
| COPD | 43 (0.7%) | 9 (0.8%) |
| CVD | 83 (1.4%) | 14 (1.2%) |
| Kidney disease without RRT | 217 (3.6%) | 11 (1.0%) |
| Heart function | ||
| NYHA classification >2 | 3428 (56.4%) | 648 (56.2%) |
| NYHA classification ≤2 | 2653 (43.6%) | 504 (43.7%) |
| LVEF >50% | 5030 (82.7%) | 978 (84.9%) |
| 35< LVEF ≤50 | 968 (15.9%) | 157 (13.6%) |
| LVEF ≤35% | 83 (1.3%) | 17 (1.5%) |
| Previous cardiac surgery | 84 (1.4%) | 25 (2.2%) |
| CM exposure | 2464 (40.5%) | 395 (34.3%) |
| Intraoperative | ||
| Emergency | 11 (0.2%) | 3 (0.3%) |
| Procedure | ||
| Valve | 3975 (65.4%) | 794 (68.9%) |
| CABG | 1527 (25.1%) | 325 (28.2%) |
| OPCAB | 286 (4.7%) | 45 (3.9%) |
| Valve and CABG | 293 (4.8%) | 47 (4.1%) |
| CPB | 4083 (67.1%) | 792 (68.8) |
| Erythrocyte transfusion, U | 1 (0, 2) | 1 (0, 2) |
| Postoperative | ||
| LCOS | 158 (2.6%) | 35 (3.1%) |
| CVP, cm H2O | 9 (7, 11) | 10 (8, 10) |
| Prognosis | ||
| 28‐day mortality | 170 (2.8%) | 39 (3.4%) |
AKI indicates acute kidney injury; CABG, coronary artery bypass grafting; CM, contrast media; COPD, chronic obstructive pulmonary disease; CPB, cardiopulmonary bypass; CVD, cerebral vascular disease; CVP, central venous pressure by ICU admittance; DM, diabetes mellitus; eGFR, estimated glomerular filtration rate, as was calculated based on the CKD‐EPI formulas; LCOS, low cardiac output syndrome; LVEF, left ventricular ejection fraction; NYHA, New York Heart Association; OPCAB, off‐pump coronary artery bypass.