Table 2 Demographic and clinical characteristics of the model construction cohort

Preoperative parameters

 Demographics

  Age (year)

53.0 ± 13.6

53.6 ± 15.1

52.5 ± 12.2

0.565

  Male (%)

172 (77.5)

77 (75.5)

95 (79.2)

0.513

  BMI (kg/m²)

26.2 ± 4.6

26.6 ± 5.1

25.9 ± 4.1

0.266

 Medical history

  Hypertension (%)

178 (80.2)

81 (79.4)

97 (80.8)

0.791

  Diabetes mellitus (%)

8 (3.6)

4 (3.9)

4 (3.3)

1.000

  Previous cardiac surgery (%)

10 (4.5)

3 (2.9)

7 (5.8)

0.349

  Cerebrovascular disease (%)

25 (11.3)

11 (10.8)

14 (11.7)

1.000

  CKD (%)

17 (7.7)

15 (14.7)

2 (1.7)

 < 0.001

   CKD stage 1 (%)

5 (2.3)

4 (3.9)

1 (0.8)

0.183

   CKD stage 2 (%)

9 (4.1)

8 (7.8)

1 (0.8)

0.013

   CKD stage 3 (%)

3 (1.4)

3 (2.9)

0 (0)

0.095

 Involving renal artery (%)

150 (67.6)

69 (67.6)

81 (67.5)

0.981

 Limb ischemia (%)

16 (7.2)

7 (6.9)

9 (7.5)

1.000

 Mesenteric ischemia (%)

7 (3.2)

4 (3.9)

3 (2.5)

0.706

 Cerebral ischemia (%)

13 (5.9)

5 (4.9)

8 (6.7)

0.577

 Coronary ischemia (%)

9 (4.1)

5 (4.9)

4 (3.3)

0.736

 Hypotension (%)

5 (2.3)

2 (2.0)

3 (2.5)

1.000

 Preoperative laboratory results

  WBC (10⁹/L)

12.0 ± 3.9

13.2 ± 4.2

11.0 ± 3.4

 < 0.001

  Hemoglobin (g/L)

129.9 ± 20.1

129.8 ± 18.5

130.0 ± 21.5

0.929

  Creatinine (μmol/L)

93.4 ± 49.2

105.0 ± 62.3

83.5 ± 31.1

0.002

  BUN (mmol/L)

7.1 ± 2.8

7.4 ± 3.0

6.7 ± 2.5

0.061

  Cystatin C (mg/L)

1.0 ± 0.4

1.1 ± 0.3

0.9 ± 0.4

 < 0.001

  eGFR (ml/min)

95.1 ± 36.4

89.4 ± 40.2

100.0 ± 32.2

0.033

  Albuminuria (%)

8 (3.6)

7 (6.9)

1 (0.8)

0.025

  D-dimer (ng/mL)

7.0 (3.8, 14.7)

6.3 (3.8, 15.1)

7.7 (4.1, 14.7)

0.428

Intraoperative parameters

 CPB duration (min)

186.5 (161.0, 224.0)

192.0 (164.8, 227.0)

183.5 (156.5, 220.8)

 < 0.001

 Cross-clamp time (min)

135.0 (113.8, 172.0)

140.0 (114.0, 172.8)

133.0 (112.3, 171.5)

 < 0.001

 Hypothermia circulation arrest time (min)

24.9 ± 10.9

24.7 ± 11.1

25.1 ± 10.7

0.789

Postoperative parameters

 Drainage volume 24 h after surgery (ml)

550.4 ± 457.8

622.9 ± 563.5

488.9 ± 334.0

0.038

 Dialysis (%)

18 (8.1)

18 (17.6)

0 (0)

 < 0.001

 Cleveland Clinic score

5.4 ± 2.5

6.2 ± 2.6

4.8 ± 2.1

 < 0.001

 Mechanical ventilation time (h)

20.8 (14.0, 83.5)

48.0 (15.8, 112.5)

18.0 (13.0, 45.0)

 < 0.001

 In-hospital death (%)

19 (8.6)

16 (15.7)

3 (2.5)

0.001

 ICU stay (days)

5.0 (3.0, 8.0)

6.0 (4.0, 11.3)

4.0 (3.0, 6.0)

 < 0.001

 Hospital stay (days)

18.6 ± 10.4

19.9 ± 11.8

17.4 ± 9.0

0.037