Perioperative neutrophil to lymphocyte ratio as a predictor of poor cardiac surgery patient outcomes

Figures & data

Table 1 Demographic, clinical, and perioperative patient characteristics

Characteristics	Mean (±SD)
Age (years)	65.5 (12)
BMI (kg/m^2)	27.9 (4.6)
Ejection fraction (%)	51.3 (11)
Duration of surgery (min)	267.1 (97.9)
Duration of cardiopulmonary bypass (min)	129 (77.9)
EuroSCORE (%)	9.4 (11.1)
	n (%)
Gender
Male	99 (68.3)
Female	46 (31.7)
COPD	26 (17.9)
DM	49 (33.8)
CRF	11 (7.6)
Cardiopulmonary bypass	129 (89)
Type of surgery
CABG	67 (46.2)
Not isolated CABG	78 (53.8)
Surgical operation
Emergency	13 (9)
Elective	132 (91)

Abbreviations: BMI, body mass index; SD, standard deviation; COPD, chronic obstructive pulmonary disease; DM, diabetes mellitus; CRF, chronic renal failure; CABG, coronary artery bypass grafting.

Table 2 Perioperative neutrophil to lymphocyte ratio

NLR	Mean (±SD)
Preoperatively	4.21 (10)
First postoperative day	14.5 (10.1)
Second postoperative day	12.1 (7.5)

Abbreviations: SD, standard deviation; NLR, neutrophil to lymphocyte ratio.

Table 3 Patient outcomes

Outcome	Mean (±SD)
ICU length of stay (days)	6.4 (15.9)
Total postoperative length of stay (days)	13.1 (16.8)
Time until tracheal extubation (h)	57.3 (323)
	n (%)
Surgical re-exploration due to mediastinal bleeding	4 (2.8)
Nosocomial pneumonia	14 (9.7)
ICU readmission	5 (3.4)
30-day mortality	19 (13.1)
In-hospital mortality	24 (16.6)

Abbreviations: SD, standard deviation; ICU, intensive care unit.

Table 4 Associations between preoperative NLR and dependent variables of the study

Variables	Median preoperative NLR	p-value
Surgical re-exploration due to mediastinal bleeding		0.681a
Yes	2.4
No	2.2
30-day mortality		0.002a
Yes	3.8
No	2.0
In-hospital mortality		0.001a
Yes	3.6
No	2.1
Nosocomial pneumonia		0.199a
Yes	3.0
No	2.1
ICU readmission		0.085a
Yes	3.7
No	2.2
Spearman’s correlation coefficient
ICU length of stay	0.251	0.002b
Total postoperative length of stay	0.196	0.018b
Time until tracheal extubation	0.363	≤0.001b

Notes:

a Kruskal–Wallis test;

b Spearman’s correlation coefficient. Bold entries denote p<0.05.

Abbreviations: ICU, intensive care unit; NLR, neutrophil-lymphocyte ratio.

Table 5 Associations between NLR at second postoperative day and dependent variables of the study

Variables	Median NLR at second postoperative day	p-value
Surgical re-exploration due to mediastinal bleeding		0.433a
Yes	17.6
No	9.7
30-day mortality		0.074a
Yes	13.7
No	9.6
In-hospital mortality		0.018a
Yes	14.0
No	9.3
Nosocomial pneumonia		0.022a
Yes	13.9
No	9.5
ICU readmission		0.002a
Yes	23.7
No	9.6
Spearman’s correlation coefficient
ICU length of stay	0.316	≤0.001b
Total postoperative length of stay	0.142	0.088b
Time until tracheal extubation	0.311	≤0.001b

Notes:

a Kruskal–Wallis Test;

b Spearman’s correlation coefficient. Bold entries denote p<0.05.

Abbreviations: ICU, intensive care unit; NLR, neutrophil-lymphocyte ratio.