Incidence and healing times of postoperative sternal wound infections: a retrospective observational single-centre study

Figures & data

Figure 1. Time to diagnosis of mediastinitis and superficial wound infection (SWI) within three months after open-heart surgery.

Table 1. Mediastinitis and superficial wound infections during 2020–2022.

Year of surgery	2020	2021	2022	Total
No. patients with sternotomy	889	904	900	2693
Superficial wound infection (%)	23 (2.6)	20 (2.2)	29 (3.3)	72 (27)
Mediastinitis (%)	3 (0.3)	4 (0.4)	6 (0.7)	13 (0.5)
Total no. infections (%)	26 (2.9)	24 (2.6)	35 (4,0)	85 (3.2)

Table 2. Baseline characteristics of patients with and without sternal wound infection after heart surgery from 2020–2022.

	No infection		Mediastinitis		Superficial infection
	(n = 2608)		(n = 13)		(n = 72)		p-value*
	Mean	SD	Mean	SD	Mean	SD
Age (yrs)	629	12.6	64.6	10.3	62.2	8.6	.85
Body mass index (kg/m^2)	27.2	4.7	29.6	4.7	28.6	4.8	<.001
Creatinine clearance (mL/min/1.73m^2)	96.4	35.4	94.6	43.0	98.4	36.2	.73
	Median	25^th–75^th percentiles	Median	25th–75th percentiles	Median	25th–75th percentiles
EuroSCORE II	4.0	2.1–7.4	2.6	1.6–5.8	4.0	2.1–5.3	.07
	n	%	n	%	n	%
Female	600	23.0	3	23.1	25	34.7	.02
Present smoker	334	12.8	3	23.1	14	19.7	.01
Hypertension	1713	65.7	9	69.2	46	63.9	.94
All diabetes	557	21.4	7	53.8	24	33.3	.001
Insulin treatment	229	8.8	5	38.5	9	12.5	.02
Obstructive pulmonary disease	253	9.7	1	7.7	7	9.9	.81
Peripheral vascular disease	158	6.1	2	15.4	7	9.9	.25
Previous myocardial infarction	580	22.2	6	46.2	26	36.7	<.001
Endocarditis	150	5.7	0		1	1.4	.19
Emergent surgery	174	6.7	0		5	6.9	.93
Urgent surgery	962	36.9	8	61.5	19	26.4	.40
Previous cardiac surgery	281	10.8	0		8	11.3	.95
Ventricular ejection fraction ≤30%	156	6.0	0		1	1.4	.10
Pulmonary pressure >30 mmHg	580	22.2	3	3	18	25.4	.17

IQR: Interquartile range; EuroSCORE: European System for Cardiac Operative Risk Evaluation Score II [14].

* Infection vs. no infection.

Table 3. Perioperative data in patients with and without sternal wound infection from 2020–2022.

	No infection		Mediastinitis		Superficial infection
	(n = 2608)		(n = 13)		(n = 72)
	Mean	SD	Mean	SD	Mean	SD	p-value*
Extra-corporeal circulation (min)	93.6	46.8	93.7	54.7	86.1	40.7	.23
Aortic occlusion time (min)	68.1	36.4	66.3	52.8	63.7	36.4	.34
	n	%	n	%	n	%
Coronary artery bypass	1191	45.6	11	84.6	48	66.7	<.001
Internal mammary artery graft	1151	44.1	10	76.9	46	63.9	.001
Bilateral mammary grafts	102	8.6**	1	9.1**	7	14.6	.28**
Valve surgery	1285	49.3	4	30.8	24	33.8	.08
Postoperative bleeding	130	5.0	2	15.4	8	11.3	.01
Postoperative stroke	64	2.5	0		1	1.4	.86
Postoperative dialysis	90	3.4	1	7.8	2	2.8	.98
Mechanical circulatory support	10	0.4	0		1	1.4	.79
Initial respirator treatment >2 d	70	2.7	1	7.8	4	5.6	.07

*Infection vs. no infection; **percent of coronary artery bypass procedures.

Table 4. Primary organisms detected in 85 sternal wounds.

Cultured organism	n
Staphylococcus aureus	21
Coagulase-negative Staphylococcus	7
Staphylococcus epidermidis	2
Normal skin flora	9
Cutibacterium acnes	5
Corynebacterium striatum	2
Enterobacter	7
Proteus mirabilis	4
Klebsiella oxytoca	12
Serratia marcescens	5
Escherichia coli	5
Morganella morganii	1
Citrobacter koseri	1
Pseudomonas aeruginosa	2
Candida albicans	2

Figure 2. Time to diagnosis of mediastinitis and superficial wound infection (SWI) after open-heart surgery in relation to time until the wound healed.

Nashef SA, Sharples LD, Roques F, et al. EuroSCORE II and the art and science of risk modelling. Eur J Cardiothorac Surg. 2013;43(4):695–696. doi: 10.1093/ejcts/ezs468.

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Data availability statement

Due to the study’s ethical consent data are not available for sharing.