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Annals of Intensive Care

Table 1 Characteristics of the patients and procedures at baseline, as well as short-term patient outcomes

From: Diagnosis of cardiac surgery-associated acute kidney injury: differential roles of creatinine, chitinase 3-like protein 1 and neutrophil gelatinase-associated lipocalin: a prospective cohort study

No. (%)
[95% CI] 		All patients
203 (100)
[98.1–100] 		AKI stage ≥1a within 48 h
95 (46.8)
[40.1–53.7] 		No AKIa within 48 h
108 (53.2)
[46.3–59.9] 		P value
Characteristic
Male sex—no. (%) [95% CI] 133 (65.5)
[58.7–71.7] 		65 (68.4)
[58.5–76.9] 		68 (63.0)
[53.6–71.5] 		0.461
White race—no. (%) [95% CI] 202 (99.5)
[97.3–99.9] 		95 (100)
[96.1–100] 		107 (99.1)
[94.9–99.8] 		1.000
Ageb (IQR)—years 70.0 (61.0–76.0) 74.0 (65.0–80.0) 67.0 (58.0–75.0) <0.001
BMI (IQR) 27 (24–29) 27 (25–31) 26 (23–29) 0.004
Medical history
Reference renal function (IQR)
 SCr—mg/dl 0.90 (0.75–1.05) 0.99 (0.81–1.16) 0.82 (0.70–0.95) <0.001
 eGFRCKD-EPI—ml/min/1.73 m2 82 (64–94) 73 (54–85) 87 (77–97) <0.001
DM—no. (%) [95% CI]     0.025
 Type 1 2 (1.0)
[0.3–3.5] 		2 (2.1)
[0.6–7.4] 		0 (0.0)
[0.0–3.4] 		 
 Type 2 46 (22.7)
[17.4–28.9] 		28 (29.5)
[21.2–39.3] 		18 (16.7)
[10.8–24.8] 		 
 No DM 155 (76.4)
[70.1–81.7] 		65 (68.4)
[58.5–76.9] 		90 (83.3)
[75.2–89.2] 		 
Heart failure—no. (%) [95% CI]     0.252
 NYHA class I 145 (71.4)
[64.9–77.2] 		64 (67.4)
[57.4–76.0] 		81 (75.0)
[66.1–82.2] 		 
 NYHA class II 36 (17.7)
[13.1–23.6] 		17 (17.9)
[11.5–26.8] 		19 (17.6)
[11.6–25.8] 		 
 NYHA class III 20 (9.9)
[6.5–14.7] 		12 (12.6)
[7.4–20.8] 		8 (7.4)
[3.8–13.9] 		 
 NYHA class IV 2 (1.0)
[0.3–3.5] 		2 (2.1)
[0.6–7.4] 		0 (0.0)
[0.0–3.4] 		 
Clinical examination
Blood pressure (IQR)—mm Hg
 Systolic 134 (122–149) 132 (122–150) 134 (120–149) 0.704
 Diastolic 72 (64–78) 72 (63–78) 71 (66–78) 0.619
 Mean 93 (85–101) 92 (84–102) 93 (86–100) 0.734
Heart rhythm—no. (%) [95% CI]     0.074
 Atrial fibrillation 16 (7.9)
[4.9–12.4] 		11 (11.6)
[6.6–19.6] 		5 (4.6)
[2.0–10.4] 		 
 Normal sinus rhythm 187 (92.1)
[87.6–95.1] 		84 (88.4)
[80.4–93.4] 		103 (95.4)
[89.6–98.0] 		 
 Heart rate in normal sinus rhythm (IQR)—bpm
(N = 187) 		69 (61–79) 70 (62–81) 69 (60–76) 0.143
Distribution of ejection fraction—no. (%) [95% CI]     0.531
 ≤20% 5 (2.5)
[1.1–5.6] 		4 (4.2)
[1.6–10.3] 		1 (0.9)
[0.2–5.1] 		 
 21–30% 3 (1.5)
[0.5–4.3] 		2 (2.1)
[0.6–7.4] 		1 (0.9)
[0.2–5.1] 		 
 31–50% 33 (16.3)
[11.8–22.0] 		16 (16.8)
[10.6–25.6] 		17 (15.7)
[10.1–23.8] 		 
 >50% 119 (58.6)
[51.7–65.2] 		55 (57.9)
[47.8–67.3] 		64 (59.3)
[49.8–68.1] 		 
Index surgical procedure
EuroSCORE (IQR) 5 (3–8) 6 (4–9) 5 (2–7) 0.004
Type of cardiac surgical procedure—no. (%) [95% CI]     0.005
 Isolated CABG 93 (45.8)
[39.1–52.7] 		34 (35.8)
[26.9–45.8] 		59 (54.6)
[45.2–63.7] 		 
 Isolated valve repair or replacement 55 (27.1)
[21.4–33.6] 		28 (29.5)
[21.2–39.3] 		27 (25.0)
[17.8–33.9] 		 
 CABG and valve repair or replacement 34 (16.7)
[12.2–22.5] 		25 (26.3)
[18.5–36.0] 		9 (8.3)
[4.4–15.1] 		 
 Aortic root 12 (5.9)
[3.4–10.0] 		5 (5.3)
[2.3–11.7] 		7 (6.5)
[3.2–12.8] 		 
 Other 9 (4.4)
[2.3–8.2] 		3 (3.2)
[1.1–8.9] 		6 (5.6)
[2.6–11.6] 		 
ECC—no. (%) [95% CI]     0.516
 Yes 179 (88.2)
[83.0–91.9] 		82 (86.3)
[78.0–91.8] 		97 (89.8)
[82.7–94.2] 		 
 No 24 (11.8)
[8.1–17.0] 		13 (13.7)
[8.2–22.0] 		11 (10.2)
[5.8–17.3] 		 
 Duration of ECC (IQR)—min
N = 179 		91.5 (70.8–123.3) 92.0 (70.3–131.3) 91.5 (70.3–117.8) 0.527
 Priming volume of ECC pump (IQR)—ml
N = 179 		1300 (1200–1500) 1300 (1200–1500) 1300 (1150–1400) 0.246
 Duration of aortic clamp during ECC (IQR)—min
N = 179 		56.0 (42.8–82.0) 62.0 (45.0–88.0) 55.0 (40.5–74.5) 0.174
 Duration of ischaemia during ECC (IQR)—min
N = 179 		54.0 (39.0–78.0) 61.0 (43.0–81.0) 52.0 (37.8–70.5) 0.164
 Duration of surgery (IQR)—h 4.6 (3.9–5.2) 4.7 (3.9–5.3) 4.5 (3.9–5.1) 0.196
 IABP peri-operatively—no. (%) [95% CI] 7 (3.4)
[1.7–6.9] 		2 (2.1)
[0.6–7.4] 		5 (4.6)
[2.0–10.4] 		0.452
Medication—no. (%) [95% CI]
Statins 127 (62.6)
[55.7–68.9] 		63 (66.3)
[56.3–75.0] 		64 (59.3)
[49.8–68.1] 		0.313
ACE inhibitors 56 (27.6)
[21.9–34.1] 		28 (29.5)
[21.2–39.3] 		28 (25.9)
[18.6–34.9] 		0.638
ARBs 7 (3.4)
[1.7–6.9] 		6 (6.3)
[2.9–13.1] 		1 (0.9)
[0.2–5.1] 		0.052
Diuretics 51 (25.1)
[19.7–31.5] 		36 (37.9)
[28.8–47.9] 		15 (13.9)
[8.6–21.7] 		<0.001
NSAIDs 4 (2.0)
[0.8–5.0] 		1 (1.1)
[0.2–5.7] 		3 (2.8)
[0.9–7.9] 		0.624
Corticosteroids 13 (6.4)
[3.8–10.6] 		8 (8.4)
[4.3–15.7] 		5 (4.6)
[2.0–10.4] 		0.390
Tacrolimus 0 (0.0)
[0.0–1.9] 		0 (0.0)
[0.0–3.9] 		0 (0.0)
[0.0–3.4] 		NA
Cyclosporine 2 (1.0)
[0.3–3.5] 		2 (2.1)
[0.6–7.4] 		0 (0.0)
[0.0–3.4] 		0.218
Aminoglycosides 3 (1.5)
[0.5–4.3] 		1 (1.1)
[0.2–5.7] 		2 (1.9)
[0.5–6.5] 		1.000
Corticosteroids intra-operatively 0 (0.0)
[0.0–1.9] 		0 (0.0)
[0.0–3.9] 		0 (0.0)
[0.0–3.4] 		NA
Iodinated contrast ≤72 h before surgery 37 (18.2)
[13.5–24.1] 		14 (14.7)
[9.0–23.2] 		23 (21.3)
[14.6–29.9] 		0.275
Outcomes
RRT in ICU—no. (%) [95% CI] 3 (1.5)
[0.5–4.3] 		3 (3.2)
[1.1–8.9] 		0 (0.0)
[0.0–3.4] 		0.101
ICU LOS (IQR)—d 1 (1–3) 2 (1–3) 1 (1–2) <0.001
Hospital LOS (IQR)—d 12 (9–16) 13 (10–20) 10 (9–13) <0.001
  1. ACE angiotensin-converting enzyme, AKI acute kidney injury, ARB angiotensin-II receptor blocker, BMI body mass index, bpm beats per minute, CABG coronary artery bypass grafting, CI confidence interval, CKD-EPI Chronic Kidney Disease Epidemiology Collaboration, DM diabetes mellitus, ECC extracorporeal circulation, eGFR estimated glomerular filtration rate, EuroSCORE European system for cardiac operative risk evaluation, h hour, IABP intra-aortic balloon pump, ICU intensive care unit, IQR interquartile range, KDIGO Kidney Disease|Improving Global Outcomes, LOS length of stay, min minute, no. number, NSAID nonsteroidal anti-inflammatory drug, NYHA New York Heart Association, RRT renal replacement therapy, SCr serum creatinine, UO urine output
  2. aKDIGO definitions for the diagnosis and staging of AKI, which are based on SCr and UO
  3. bDetermined at the day of surgery
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