Table 1 Baseline characteristics of patients with different degree of hidden renal dysfunction

 Age

53.00 ± 14.00

48 ± 15

58 ± 12 ^a

61 ± 15

 Gender (male)

1003 (57.51%)

485 (58.50%)

483 (56.36%)

35 (60.34%)

 BMI (kg/m²)

22.8 ± 3.5

22.4 ± 3.6

23.1 ± 3.4 ^a

23.5 ± 3.1

 Hypertension (n, %)

540 (30.96%)

223 (26.90%)

290 (33.84%)^b

27 (46.55%)

 DM (n, %)

200 (11.47%)

89 (10.74%)

100 (11.67%)

11 (18.97%)

 NYHA > II (n, %)

1055 (60.49%)

445 (53.68%)

571 (66.63%)

39 (67.24%)

 LVEF (%)

63.00 ± 6.00

68.00 ± 6.00

61.00 ± 5.00 ^a

60.00 ± 5.00

 BUN (mmol/L)

6.60 ± 2.20

5.90 ± 1.60

7.00 ± 2.20 ^ab

9.60 ± 3.40

 SCr (mg/dL)

0.87 ± 0.22

0.74 ± 0.12

0.96 ± 0.15 ^ab

1.09 ± 0.12

 Uric acid (μmol/L)

366.40 ± 114.30

334.10 ± 98.80

390.20 ± 112.50 ^ab

457.20 ± 126.70

 Proteinuria (n, %)

140 (8.03%)

65 (7.84%)

63 (7.35%)^b

12 (20.69%)

 Urinalysis abnormal (n, %)

279 (16.00%)

132 (15.92%)

134 (15.64%)

13 (22.41%)

 Renal ultrasound abnormal (n, %)

32 (1.83%)

9 (1.09%)

17 (1.98%) ^b

6 (10.34%)

 Hemoglobin (g/L)

133.80 ± 19.60

134.30 ± 20.40

133.50 ± 18.60

130.40 ± 21.50

 Platelet (10 ⁹/L)

181.00 ± 61.20

183.90 ± 64.40

178.10 ± 57.40

181.10 ± 68.10

  − Valve

903 (51.78%)

434 (52.35%)

445 (51.93%)

24 (41.38%)

  − CABG/OPCAB

309 (17.72%)

111 (13.39%)

185 (21.59%)

13 (22.41%)

  − Aneurysm

108 (6.19%)

57 (6.88%)

42 (4.90%)

9 (15.52%)

  − Combined

140 (8.03%)

58 (7.00%)

74 (8.63%)

8 (13.79%)

 CPB duration (min)

96.10 ± 40.90

94.40 ± 39.70

96.70 ± 41.20 ^b

112.70 ± 50.10

 Aortic clamping time (min)

47.40 ± 42.30

47.90 ± 43.40

46.90 ± 41.30

47.10 ± 39.30

 Intra-operative hypotension (n, %)

135 (7.7%)

58 (7.0%)

68 (7.9%) ^b

9 (15.5%)

 High dose of vasoactive agents (n, %)

271 (15.5%)

104 (12.5%)

153 (17.9%)

14 (24.1%)

 LCOS (n, %)

118 (6.8%)

51 (6.1%)

59 (6.9%)

8 (13.9%)