Table 1.
Characteristics of the Overall Cohort
| No AKI | AKI | P1 Value* | P2 Value# | |||
|---|---|---|---|---|---|---|
| Stage 1 | Stage 2 | Stage 3 | ||||
| Patient population (n) | 169 | 153 | 49 | 28 | ||
| Demographic data | ||||||
| Age (y) | 52.0 (18.0) | 54.0 (16.5) | 50.0 (13.0) | 41.5 (17.5) | 0.9 | 0.004 |
| Sex, male (n) | 112 (66.3%) | 116 (75.8%) | 34 (69.4%) | 21 (75.0%) | 0.08 | 0.3 |
| Height (cm) | 170.0 (13.0) | 170.0 (8.5) | 170.0 (14.0) | 169.0 (10.0) | 0.7 | 1.0 |
| Weight (kg) | 70.0 (16.0) | 72.0 (18.0) | 74.0 (24.0) | 75.0 (20.0) | 0.002 | 0.02 |
| BMI (kg/m2) | 24.6 (5.1) | 25.7 (5.8) | 25.2 (4.9) | 27.4 (5.8) | 0.003 | 0.009 |
| Medical history | ||||||
| Diabetes (n) | 4 (2.4%) | 4 (2.6%) | 3 (6.1%) | 1 (3.6%) | 0.5 | 0.6 |
| Hypertension (n) | 74 (43.8%) | 85 (55.6%) | 34 (69.4%) | 23 (82.1%) | < 0.001 | < 0.001 |
| Chronic obstructive pulmonary disease (n) | 4 (2.4%) | 6 (3.9%) | 1 (2.0%) | 0 (0.0%) | 0.7 | 0.6 |
| Previous myocardial infarction (n) | 1 (0.6%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 0.2 | 0.7 |
| Peripheral vascular disease (n) | 13 (7.7%) | 11 (7.2%) | 5 (10.2%) | 1 (3.6%) | 0.9 | 0.8 |
| Smoking (n) | 57 (33.7%) | 59 (38.6%) | 19 (38.8%) | 12 (42.9%) | 0.3 | 0.7 |
| Preoperative laboratory tests | ||||||
| Platelet (109/L) | 197.0 (71.0) | 186.5 (71.8) | 199.0 (65.5) | 166.5 (68.3) | 0.006 | 0.01 |
| Lymphocyte (109/L) | 1.63 (0.74) | 1.58 (0.90) | 1.18 (0.72) | 1.48 (0.90) | 0.004 | 0.001 |
| Monocyte (109/L) | 0.44 (0.30) | 0.51 (0.40) | 0.79 (0.78) | 0.91 (0.70) | < 0.001 | < 0.001 |
| Neutrophil (109/L) | 4.22 (2.95) | 4.86 (4.30) | 7.51 (5.64) | 10.1 (5.3) | < 0.001 | < 0.001 |
| Hyperlipidemia (n) | 55 (34.4%) | 44 (31.0%) | 7 (14.9%) | 10 (43.5%) | 0.2 | 0.04 |
| Retinol binding protein (mg/L) | 35.7 (16.2) | 37.8 (18.7) | 26.4 (24.7) | 37.3 (22.5) | 0.7 | 0.007 |
| Urinary protein | ||||||
| +/− | 17 (11.6%) | 25 (18.8%) | 10 (23.8%) | 4 (20.0%) | 0.05 | 0.2 |
| + | 14 (9.5%) | 20 (15.0%) | 11 (26.2%) | 8 (40.0%) | 0.01 | 0.005 |
| ++ | 1 (0.7%) | 2 (1.5%) | 2 (4.8%) | 1 (5.0%) | 0.2 | 0.3 |
| INR | 1.04 (0.12) | 1.04 (0.1) | 1.09 (0.15) | 1.10 (0.2) | 0.05 | 0.02 |
| Preoperative renal function | ||||||
| Preoperative SCr (μmol/L) | 70.4 (21.79) | 73.6 (23.1) | 66.0 (26.3) | 76.0 (45.7) | 0.3 | 0.07 |
| > 106 (n) | 11 (6.5%) | 13 (8.5%) | 4 (8.2%) | 8 (28.6%) | 0.1 | 0.002 |
| eGFR(mL/min/1.73 m2) | 99.8 (22.0) | 97.2 (21.2) | 103.4 (18.2) | 94.4 (39.5) | 0.2 | 0.08 |
| Preoperative cardiovascular status | ||||||
| Marfan syndrome (n) | 14 (8.3%) | 3 (2.0%) | 1 (2.0%) | 1 (3.6%) | 0.005 | 0.04 |
| Aortic dissection (n) | 56 (33.1%) | 71 (46.4%) | 36 (73.5%) | 24 (85.7%) | < 0.001 | < 0.001 |
| Stanford type-A aortic dissection (n) | 53 (31.4%) | 71 (46.4%) | 34 (69.4%) | 24 (85.7%) | < 0.001 | < 0.001 |
| Intraoperative blood product use | ||||||
| Erythrocytes (u) | 2.0 (2.0) | 4.0 (3.9) | 4.0 (6.0) | 4.0 (4.5) | 0.001 | < 0.001 |
| Fresh frozen plasma (ml) | 400.0 (200.0) | 400.0 (150.0) | 400.0 (375.0) | 600.0 (500.0) | 0.06 | 0.002 |
| Platelets (u) | 1.0 (0.0) | 1.0 (1.0) | 1.0 (1.0) | 2.0 (1.0) | 0.002 | < 0.001 |
| Surgical details | ||||||
| Involving the aortic arch (n) | 79 (46.7%) | 97 (63.4%) | 38 (77.6%) | 26 (92.9%) | < 0.001 | < 0.001 |
| Involving the descending aorta (n) | 43 (25.4%) | 60 (39.2%) | 33 (67.3%) | 24 (85.7%) | < 0.001 | < 0.001 |
| CPB duration(min) | 133.0 (75.5) | 165.0 (79.0) | 201.0 (67.5) | 220.0 (52.0) | < 0.001 | < 0.001 |
| DHCA or MHCA (n) | 58 (34.3%) | 76 (49.7%) | 34 (69.4%) | 25 (89.3%) | < 0.001 | < 0.001 |
| Aortic cross-clamp time (min) | 86.0 (27.0) | 90.0 (31.0) | 96.0 (32.0) | 113.0 (32.0) | < 0.001 | < 0.001 |
| Operation time (h) | 6.0 (2.0) | 7.0 (2.0) | 8.5 (2.0) | 9.0 (2.5) | < 0.001 | < 0.001 |
| Combined surgery | ||||||
| Valvular surgery (n) | 94 (55.6%) | 67 (43.8%) | 10 (20.4%) | 3 (10.7%) | < 0.001 | < 0.001 |
| Outcomes | ||||||
| Renal replacement therapy (n) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 12 (42.9%) | 0.003 | < 0.001 |
| Length of ICU stay (day) | 3.0 (2.0) | 4.0 (2.5) | 5.0 (4.0) | 10.5 (11.0) | < 0.001 | < 0.001 |
| > 7 d (n) | 19 (11.2%) | 20 (13.1%) | 17 (34.7%) | 23 (82.1%) | < 0.001 | < 0.001 |
| Intubation time (h) | 15.0 (9.0) | 17.0 (27.5) | 38.0 (72.5) | 136.0 (110.3) | < 0.001 | < 0.001 |
| > 5 d (n) | 4 (2.4%) | 5 (3.3%) | 6 (12.2%) | 17 (60.7%) | < 0.001 | < 0.001 |
| Stroke (n) | 0 (0.0%) | 4 (2.6%) | 0 (0.0%) | 2 (7.1%) | 0.04 | 0.01 |
| Redo surgery (n) | 4 (2.4%) | 6 (3.9%) | 6 (12.2%) | 6 (21.4%) | 0.02 | < 0.001 |
| In-hospital mortality (n) | 2 (1.2%) | 1 (0.7%) | 1 (2.1%) | 8 (28.6%) | 0.07 | < 0.001 |
Abbreviations: BMI body mass index, INR International Normalized Ratio, SCr Serum Creatinine, eGFR Estimated Glomerular Filtration Rate, CPB Cardiopulmonary Bypass, DHCA Deep Hypothermia and Circulatory Arrest, MHCA Median Hypothermia and Circulatory Arrest
NOTE. The categorical variables in the table are presented by the number of cases (with percentage) and the continuous variables are expressed by the median (with interquartile range) or mean (with standard deviation).
*P1 Value: Compare the patients without AKI and all patients with AKI. P1 values* were the results of unpaired t-test or Mann-Whitney U test for continuous variables, and χ2 test or Fisher’s exact test for categorical variables.
#P2 Value: Compare patients within four groups (without AKI and patients with stage 1, 2 and 3 AKI). P2 values# were the results of one-way analysis of variance or KruskalWallis test for continuous variables, and χ2 test or Fisher’s exact test for categorical variables