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Table 1 Demographics and risk factors of derivation and validation cohorts

From: A novel nomogram to predict perioperative acute kidney injury following isolated coronary artery bypass grafting surgery with impaired left ventricular ejection fraction

Risk factors

Definition

Derivation cohort(n = 1208)

N (%)

Validation cohort (n = 540) N (%)

P value

Age > 65 years

Older than 65 years

347 (28.7)

200 (37)

< 0.001

Female

 

174 (14.4)

83 (15.4)

0.65

SCr > 2 mg/dl

Serum creatinine measured before surgery > 2 mg/dl

13 (1.1)

6 (1.1)

1

Chronic kidney disease

Documented past history or fulfilled the criteria of KDIGO 2012

5 (0.4)

10 (1.9)

0.006

Extracardiac arteriopathy

Any one or more of the following: claudication, carotid occlusion or > 50% stenosis, previous or planned intervention on the abdominal aorta, and limb arteries or carotids

98 (8.1)

14 (2.6)

< 0.001

Cerebrovascular accident

Documented past history of coma≥24 h or central nervous system dysfunction≥72 h

42 (3.5)

41 (7.6)

0.003

History of smoking

Prior history of smoking, regardless of whether the patients quit smoking

988 (81.8)

276 (51.1)

< 0.001

Previous cardiac surgery

One or more previous major cardiac operation involving opening the pericardium

45 (3.7)

2 (0.4)

< 0.001

COPD

Long-term use of bronchodilators or steroids for lung disease

6 (0.5)

8 (1.5)

0.07

Diabetes mellitus

Documented past history or fulfilled the criteria of WHO 1999

324 (26.8)

218 (40.4)

< 0.001

NYHA class III or IV

NYHA classification

624 (51.7)

237 (43.9)

0.003

CCS angina class = 4

CCS class 4 angina (inability to perform any activity without angina or angina at rest)

126 (10.4)

7 (1.3)

< 0.001

LVEF< 35%

Assessed by echocardiography (measured before surgery)

85 (7)

45 (8.3)

0.39

History of myocardial infarction

Documented history or ECG evidence including recent myocardial infarction (< 21 days)

564 (46.7)

278 (51.5)

0.07

Previous PCI

Documented history

102 (8.4)

78 (14.4)

< 0.001

Non-elective surgery

Not routine admission for operation

62 (5.1)

11 (2.1)

0.004

Hypertension

Documented past history or SBP > 140 mmHg and/or DBP > 90 mmHg

649 (53.7)

308 (57)

0.217

On-pump surgery

With extracorporeal circulation

648 (53.6)

70 (13)

< 0.001

Perioperative IABP

Intra-aortic balloon pump used before or after surgery

14 (1.2)

82 (15.2)

< 0.001

Ventilation time > 24 h

Ventilation time longer than 24 h

249 (20.6)

94 (17.4)

0.1352

Perioperative transfusion

Transfusion before or after surgery

140 (11.6)

154 (28.5)

< 0.001

AKI

Fulfilled the criteria of KDIGO 2012

90 (7.5)

104 (19.3)

< 0.001

  1. AKI acute kidney injury, CCS Canadian cardiovascular society, COPD chronic obstructive pulmonary disease, DBP diastolic blood pressure, ECG electrocardiography, LVEF left ventricular ejection fraction, NYHA New York heart association, PCI percutaneous coronary intervention, SBP systolic blood pressure, WHO world health organization