Table 1. Patient Characteristics by Duration of AKI (n = 1194).
| Characteristic | No AKI 0 days (n = 788) | 1–2 days (n = 250) | 3–6 days (n = 118) | ≥ 7 days (n = 38) | P value |
|---|---|---|---|---|---|
| Demographics | |||||
| Age at the time of surgery, mean (SD) | 71.1 (10.3) | 71.8 (9.8) | 71.1 (10.3) | 73.3 (7.7) | 0.49 |
| Men | 525 (67%) | 176 (70%) | 85 (72%) | 29 (76%) | 0.33 |
| White race | 740 (94%) | 235 (94%) | 112 (95%) | 31 (82%) | 0.02 |
| Medical History (prior to surgery) | |||||
| Diabetes | 294 (37%) | 95 (38%) | 58 (49%) | 24 (63%) | <0.01 |
| Hypertension | 605 (77%) | 205 (82%) | 102 (86%) | 31 (82%) | 0.05 |
| Congestive Heart Failure | 175 (22%) | 65 (26%) | 49 (42%) | 18 (47%) | <0.01 |
| LVEF < 40% | 77 (10%) | 29 (12%) | 11 (9%) | 1 (3%) | 0.37 |
| Previous myocardial infarction | 197 (25%) | 61 (24%) | 36 (31%) | 10 (26%) | 0.61 |
| eGFR (mL/min per 1.73 m2), mean (SD) | 69.2 (18.9) | 66.4 (18.3) | 61.3 (21.5) | 57.2 (20.4) | <0.01 |
| eGFR ≥ 60 | 548 (70%) | 164 (66%) | 56 (48%) | 18 (47%) | <0.01 |
| eGFR 30-<60 | 223 (28%) | 79 (32%) | 52 (44%) | 18 (47%) | |
| eGFR < 30 | 17 (2%) | 7 (3%) | 10 (9%) | 2 (5%) | |
| Pre-op Serum Creatinine§ (mg/dL), mean (SD) | 1.05 (0.32) | 1.10 (0.31) | 1.23 (0.45) | 1.30 (0.38) | <0.01 |
| Urine albumin to Creatinine, mg/mmol | |||||
| < = 10.0 | 341 (43%) | 83 (33%) | 26 (22%) | 6 (16%) | <0.01 |
| 10.0-<30 | 229 (29%) | 74 (30%) | 32 (27%) | 12 (32%) | |
| 30–300 | 188 (24%) | 77 (31%) | 43 (36%) | 14 (37%) | |
| >300 | 30 (4%) | 16 (6%) | 17 (14%) | 6 (16%) | |
| Surgical Characteristics | |||||
| Elective Surgery | 656 (83%) | 190 (76%) | 78 (66%) | 26 (68%) | <0.01 |
| Surgery | |||||
| CABG | 392 (50%) | 121 (48%) | 52 (44%) | 12 (32%) | 0.03 |
| CABG & Valve | 162 (21%) | 56 (22%) | 35 (30%) | 16 (42%) | |
| Valve | 234 (30%) | 73 (29%) | 31 (26%) | 10 (26%) | |
| Off-pump | 85 (11%) | 20 (8%) | 12 (10%) | 6 (16%) | 0.02 |
| Re-do surgery | 14 (2%) | 4 (2%) | 1 (1%) | 1 (3%) | 0.87 |
| Perfusion time (minutes), mean (SD) | 106.6 (52.7) | 119.1 (59.6) | 129.4 (74.2) | 168.4 (91.3) | <0.01 |
| Cross-clamp time (minutes), mean (SD) | 72.7 (40.0) | 80.7 (44.7) | 90.9 (53.3) | 114.4 (67.3) | <0.01 |
| Number of Diseased Coronary Vessels | |||||
| None | 219 (28%) | 65 (26%) | 26 (22%) | 11 (29%) | 0.78 |
| One | 106 (14%) | 35 (14%) | 13 (11%) | 2 (5%) | |
| Two | 149 (19%) | 47 (19%) | 22 (19%) | 6 (16%) | |
| Three | 314 (40%) | 103 (41%) | 57 (48%) | 19 (50%) | |
| Post-operative Complications | |||||
| AKIN stage | |||||
| Stage 1 | 0 | 243 (97%) | 95 (81%) | 20 (53%) | |
| Stage 2 | 0 | 6 (2%) | 14 (12%) | 10 (26%) | |
| Stage 3 | 0 | 1(0%) | 9 (8%) | 8 (21%) | |
| Oliguria‡ in first day, n (%) | 8 (1%) | 3 (1%) | 2 (2%) | 2 (5%) | 0.31 |
| Delta Peak Serum creatinine (mg/dL), mean (SD) | 0.03 (0.14) | 0.37 (0.23) | 0.75 (0.51) | 0.98 (0.72) | <0.01 |
| # Non-renal complications†, n (%) | |||||
| 0 | 507 (64%) | 152 (61%) | 63 (53%) | 6 (16%) | <0.01 |
| 1–2 | 232 (29%) | 77 (31%) | 37 (31%) | 14 (37%) | |
| >2 | 49 (6%) | 21 (8%) | 18 (15%) | 18 (47%) | |
| Ventilator > 48 hours, n (%) | 8 (1%) | 11 (4%) | 10 (8%) | 16 (42%) | <0.01 |
| ICU LOS, mean (SD) | 2.32 (4.11) | 3.41 (7. 419) | 3.64 (3.90) | 20.32 (32.75) | <0.01 |
| Hospital LOS, mean (SD) | 6.89 (5.29) | 9.32 (11.34) | 9.18 (4.86) | 32.05 (35.09) | <0.01 |
Data are presented as the mean (SD), n (%), or median (interquartile range) unless otherwise specified. eGFR, estimated GFR; SCr, serum creatinine.
§To convert serum creatinine values to millimoles per liter, multiply by 88.4.
‡Oliguria is defined as a patient who had 125 ml or 500 ml urine output in 6 or 24 hours, respectively.
†Nonrenal complications are defined as reoperation, infection, neurologic, pulmonary, vascular, and other.