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RESEARCH ARTICLE
SA JOURNAL OF DIABETES & VASCULAR DISEASE
76
VOLUME 13 NUMBER 2 • DECEMBER 2016
reported the rate of CoNS in surgical wound infections as 14%. It
is known that CoNS are also the predominant bacteria in DSWI.
11
SWI are divided into two subgroups: superficial sternal wound
infection (SSWI) and deep sternal wound infection (DSWI). While
SSWI involves only subcutaneous tissue, DSWI is associated with
sternal osteomyelitis and sometimes with infected retrosternal
space (termed mediastinitis).
12
Studies have reported that DSWI
occurs in 0.25 to 2.3% of patients.
13-17
While re-opening and debridement of the mediastinum is
required in the treatment of DSWI, administration of antibiotics is
generally sufficient to treat SSWI. In the present study, only one
patient (1/151, 0.66%) in the control group developed SSWI and
was treated with the administration of antibiotics.
DSWI occurring after CABG operation has a multifactorial
aetiology, with a potential risk of death and high hospital costs.
18
Many studies have suggested the underlying aetiology of DSWI
occurring after CABG to be obesity, advanced age, prolonged CPB
duration, diabetes, high creatinine levels, use of bilateral internal
mammary artery grafts, and unnecessary use of electrocautery.
14,18-21
Recent studies have suggested that DSWI is associated with obesity
and re-operation, and also indicated that use of bilateral internal
mammary artery grafts, duration and complexity of the operation,
and diabetes are other risk factors.
22
It is well known that mobilisation of the internal mammary
artery causes sternal devascularisation and the resultant ischaemia
contributes to sternal dehiscence or infection.
14,22
In the present
study, according to the ACC/AHA 2004 guideline,
5
the pre-operative
mediastinitis risk percentage of one patient who developed SSWI
was 0.5%, due to the risk factors, advanced age and the presence
of diabetes. Although this patient was not a dialysis patient, he/she
had a high creatinine level (2.5 mg/dl).
In a 10-year retrospective study of 5 440 patients who
underwent cardiac surgery, Khanlari
et al
.
6
evaluated 100 patients
with staphylococcal DSWI developing after cardiac surgery. They
reported that a rifampicin-containing antibiotic regimen significantly
improved the outcomes during a one-year follow-up period.
Many factors have been implicated in the occurrence of DSWI
after cardiac surgery. However, there is no consensus on which is
the most important and best predictive factor.
23
On the other hand,
diabetes has emerged as a significant risk factor of cardiovascular
surgeons, for the development of DSWI after CABG operation.
In terms of the pathophysiological consequences of diabetes,
microvascular changes and elevated blood glucose levels impair
the healing process of surgical wounds.
24,25
The present study
is distinctive in that it examined patients who were on oral anti-
diabetic agents or insulin therapy.
Conclusion
Although the difference in the rate of superficial sternal wound
infection between the rifamycin and control groups was not
statistically significant, locally applied rifamycin SV during closure of
the sternum after CABG surgery may have had a protective affect
against SWI.
Acknowledgements
We thank Associate Prof Ismail Keskin of the Department of
Biometry and Genetics, Selçuk University, Konya, Turkey for his
contribution to evaluation of the results and statistical analysis.
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