Table 1.
Patient characteristics of 106 subjects who underwent cardiac surgery with CPB stratified by the occurrence of postoperative in-hospital AKI
| All n = 106 | AKI n = 23 | No-AKI n = 83 | P | |
|---|---|---|---|---|
| Preoperative characteristics | ||||
| Age, yr, mean ± SD | 61 ± 12 | 62 ± 12 | 61 ± 12 | 0.83 |
| Female, % | 29 (27.4) | 6 (26.1) | 23 (27.7) | 0.88 |
| Race, % | 0.70 | |||
| White | 68 (64.1) | 13 (56.5) | 55 (66.3) | |
| Black | 14 (13.2) | 4 (17.4) | 12 (14.5) | |
| Other | 24 (22.6) | 6 (26.1) | 16 (19.3) | |
| Obesity, BMI >30 kg/m2, % | 50 (47.2) | 18 (78.3) | 32 (38.6) | <0.001 |
| Diabetes mellitus, % | 35 (33.0) | 7 (30.4) | 28 (33.7) | 0.77 |
| Hypertension, % | 21 (19.8) | 21 (91.3) | 64 (77.1) | 0.15 |
| Hypercholesterolemia, % (n = 105) | 72 (68.6) | 18 (78.3) | 54 (65.9) | 0.26 |
| Tobacco smoking, % | 0.73 | |||
| Current smoker | 9 (8.5) | 2 ( 8.7) | 7 ( 8.4) | |
| Past smoker | 54 (50.9) | 10 (43.5) | 44 (53.0) | |
| Never smoker | 43 (40.6) | 11 (47.8) | 32 (38.6) | |
| Baseline eGFR, ml/min per 1.73 m2, mean ± SD | 71.0 ± 23.3 | 71 ± 24 | 79 ± 23 | 0.18 |
| Baseline eGFR < 60 ml/min per 1.73 m2 | 23 (21.7) | 6 (26.1) | 17 (20.5) | 0.58 |
| Left ventricular ejection fraction %, mean ± SD | 57 ± 9.9 | 50 ± 12 | 59 ± 8 | <0.001 |
| History of preoperative arrhythmia, % | 16 (15.1) | 5 (21.7) | 11 (13.3) | 0.33 |
| History of heart failure, % | 32 (30.2) | 9 (39.1) | 23 (27.7) | 0.29 |
| History of thyroid disease, % | 12 (11.3) | 1 (4.3) | 11 (13.3) | 0.46 |
| Anemia, % | 35 (33.0) | 7 (30.4) | 28 (33.7) | 0.77 |
| Cleveland Clinic preoperative score,30 median (IQR) | 2 (1, 4) | 3 (1, 5) | 2 (1, 4) | 0.40 |
| Preoperative medications | ||||
| ACEI or ARB, % | 65 (61.3) | 18 (78.3) | 47 (56.6) | 0.09 |
| Loop diuretic, % | 36 (34.0) | 11 (47.8) | 25 (30.1) | 0.11 |
| Statin, % | 76 (71.7) | 17 (73.9) | 59 (71.1) | 0.79 |
| Beta blocker (within 24 h of surgery), % | 58 (54.7) | 15 (65.2) | 43 (51.8) | 0.25 |
| Calcium channel blocker, % | 24 (22.6) | 4 (17.4) | 20 (24.1) | 0.58 |
| Aspirin, % | 71 (67.0) | 16 (69.6) | 55 (66.3) | 0.77 |
| Nonaspirin platelet inhibitor, % | 10 (9.4) | 2 (8.7) | 8 (9.6) | 1.00 |
| Surgical, intraoperative, and postoperative characteristics | ||||
| CPB time, minutes, median (IQR) | 121 (104, 161) | 125 (105, 180) | 121 (103, 161) | 0.48 |
| Aortic cross-clamp time, minutes, median (IQR) | 85 (70, 113) | 87 (72, 114) | 85 (68, 112) | 0.49 |
| Type of cardiac surgery, % | 0.36 | |||
| CABG only | 43 (40.6) | 10 (43.5) | 33 (39.8) | |
| CABG plus valve | 11 (10.4) | 4 (17.4) | 7 (8.4) | |
| Valve only | 52 (49.1) | 9 (39.1) | 43 (51.8) | |
| Reoperative cardiac surgery, % | 12 (11.3) | 4 (17.4) | 8 (9.6) | 0.29 |
| Nadir intraoperative hemoglobin, g/dl, mean ± SD | 7.8 ± 1.5 | 7.4 ± 1.5 | 7.9 ± 1.5 | 0.16 |
| Intraoperative PRBC transfusion, % | 33 (31.1) | 7 (30.4) | 26 (31.3) | 0.94 |
| PRBC transfused intraoperative + 24 h after surgery, % | 44 (41.5) | 12 (52.2) | 32 (38.6) | 0.24 |
| ICU length of stay, d, median (IQR) | 2 (1, 4) | 4 (2, 6) | 2 (1, 3) | <0.001 |
| Hospital length of stay, d, median (IQR) | 7 (6, 9) | 9 (7, 13) | 6 (5, 8) | <0.001 |
| Urine output first 24 h after surgery, liters, median (IQR) | 1.72 (1.29, 2.10) | 1.29 (1.10, 1.72) | 1.86 (1.51, 2.17) | 0.004 |
ACEI, angiotensin-converting enzyme inhibitor; AKI, acute kidney injury; ARB, angiotensin-II receptor blocker; BMI, body mass index; CABG, coronary artery bypass graft; CPB, cardiopulmonary bypass; eGFR, estimated glomerular filtration rate; ICU, intensive care unit; IQR, interquartile range; PRBC, packed red blood cell.
Data are shown as n (%) for categorical variables and mean ± SD or median (IQR = 25th and 75th percentile) for continuous variables.