Surgical site infections following coronary artery bypass graft procedures: 10 years of surveillance data

Table 1 Demographic and clinical characteristics of patients undergoing coronary artery bypass graft (CABG) procedures, 2003-2012

Characteristic*	N	%
Number of hospitals	3
Number of patients undergoing CABG procedures	14,517
Sex
Male	11,379	78.4
Female	3,138	21.6
Age, median (interquartile range), years	66 (58 – 73)
Age category, years
<55	2,357	16.2
55-64	3,941	27.2
65-74	5,150	35.5
75+	3,069	21.1
ASA (American Society of Anaesthesiologists) score
1	6	0.1
2	164	1.1
3	7,787	54.1
4	6,349	44.1
5	83	0.6
Priority of surgery
Emergency	1,462	10.2
Elective	12,896	89.8
Types of CABG
CABG with both sternal and graft site incisions	13,637	93.9
CABG with sternal site incisions only	880	6.1
Wound classification
Clean	14,286	98.4
Clean-contaminated	228	1.6
Mean number of grafts	2.9
Category of graft numbers
1	1,394	9.6
2	3,218	22.2
3	5,846	40.3
4	3,197	22.1
5+	837	5.8
Antibiotic prophylaxis
Yes	13,851	96.7
No	466	3.3

*Five variables with missing values: ASA score (128, 0.9%), priority of surgery (159, 1.1%), wound classification (3, 0.02%), category of graft numbers (25, 0.2%), and antibiotic prophylaxis (200, 1.4%).