CARDIOVASCULAR JOURNAL OF AFRICA • Volume 25, No 3, May/June 2014
AFRICA
97
to undergo isolated CABG surgery in the Department of
Cardiovascular Surgery, Mevlana University between July 2008
and July 2011 were prospectively enrolled. Of these patients,
eight were excluded due to use of the intra-operative beating-
heart technique, a need for revision in the post-operative period,
or death.
In the remaining 151 patients, the risk of mediastinitis was
assessed according to the ACC/AHA 2004 guideline update
for CABG surgery.
5
We grouped the patients according to
their mediastinitis risk scores into two comparable groups: the
rifamycin group consisted of 78 patients (52 male, mean age
62
±
8 years) who received local antibiotic rifamycin SV i.m.
(Rif
®
250 mg/3-ml ampoule) on the sternal region after CABG
surgery, and the control group consisted of 73 patients (45 male,
mean age 61
±
8 years). They did not receive a local antibiotic.
The local ethics committee approved the study. Written
informed consent was obtained from the patients. It was
determined prior to the initiation of the study that patients
developing SSWI would be treated by the administration of
antibiotics alone. Patients developing DSWI would be treated by
the administration of antibiotics plus surgery.
During the pre-operative period, all patients were assessed
for the risk of mediastinitis according to the ACC/AHA 2004
guideline for CABG surgery,
5
using eight parameters including
age, presence of obesity, diabetes or COPD, the need for dialysis,
ejection fraction (EF)
<
40%, and scheduled for emergency
surgery. Baseline characteristics, parameters used to assess the
risk of mediastinitis, and post- and intra-operative data of the
patients are presented in Table 1.
Skin cleansing was performed in all patients prior to surgery.
Combined insulin therapy with regular human insulin (Humulin
®
R 100 U/ml) and insulin glargine (Lantus
®
100 U/ml) was
administered to control blood glucose levels below 200 mg/dl
during pre-, intra- and postoperative periods. Insulin infusion
was initiated in patients as required. The standard prophylactic
antibiotic regimen used in our clinic was administered to
patients, that is 1 g cefazolin sodium (Cefamezin-IM/IV
®
) 30
minutes before surgery and 1 g every eight hours after surgery
for 48 hours.
Cardiopulmonary bypass (CPB) duration, cross-clamping
times and number of grafts in both groups are shown in Table
1. Only left internal mammary artery grafts were used in all
patients. Meticulous aseptic techniques were used during the
operation and unnecessary use of electrocautery and excessive
perfusion in CPB were avoided.
All patients were kept in the intensive care unit for 24 hours
and the patients were referred to a regular ward within the second
24 hours after drains and arterial catheters were removed. Central
venous catheters were removed on the second postoperative day.
The patients were discharged on postoperative day 6
±
3.
In the rifamycin group, mediastinum, sternum and suprasternal
tissues were irrigated after surgery using rifamycin SV i.m. (Rif
®
250 mg/3-ml ampoule) diluted with 10 ml isotonic solution. In
the control group, irrigation was not performed. The two groups
were compared with regard to risk for sternal infection.
Statistical analysis
Statistical analysis was performed using statistical package
for social sciences 13.0 (SPSS Inc, Chicago, IL, USA). The
Kolmogorov-Smirnov test was used to determine the distribution
of numerical parameters. Continuous variables are presented
as mean
±
standard deviation. For comparison of independent
continuous variables, the Student’s
t
-test or Mann–Whitney
U
-test was used where appropriate. Categorical data were
compared using the Fisher’s exact test or chi-square test. For
all statistics, a
p
-value
<
0.05 was considered statistically
significant.
Results
There were no significant differences between the two groups
in terms of baseline characteristics and mediastinitis risk
percentages (Table 1).
The patients were followed up for the development of SWI
for 30 days after the surgery. In neither group did DSWI occur.
While no SSWI was observed in the rifamycin group, it was
observed in one patient in the control group (0/78 vs 1/73,
p
=
0.303). This patient, who used oral anti-diabetic medication,
was 75 years old and had a serum creatinine level below 2.5 mg/
dl, had a low risk profile (total risk score: 3 and pre-operative
mediastinitis risk percentage: 0.5%), according to the ACC/AHA
2004 guideline.
5
Wound culture was performed and coagulase-negative
staphylococci (CoNS) were observed. The patient was put on
appropriate antibiotic therapy with sodium fusidate (Stafine
®
tablet 500 mg) three times daily and rifampicin (Rifcap
®
capsule
150 mg) twice daily. The infection regressed and the patient was
discharged after a full recovery.
The amount of drainage in the control group, particularly in
four patients, was higher than in the patients in the rifamycin
group, however, the difference was not statistically significant.
This was attributed to the pre-operatively administered antiplatelet
agents rather than to surgical reasons, and re-exploration was not
required. However, none of the four patients developed sternal
infection. None of the patients required re-exploration due to
bleeding, tamponade or for other reasons.
Table 1. Baseline clinical characteristics of the study groups.
Group 1
(
n
=
78)
Group 2
(
n
=
73)
p
-value
Age (years)
62
±
8
61
±
8
0.605
Sex (F/M)
26/52
28/45
0.635
BMI (kg/m
2
)
28.9
±
4.6 29.1
±
4.2
0.796
Mediastinitis risk score
0.7
±
0.4
0.7
±
0.4
0.570
Number of grafts (
n
)
3.2
±
1.0
3.3
±
1.0
0.557
CABG time (min)
104
±
30
105
±
27
0.896
Cross-clamp (min)
70
±
21
71
±
20
0.687
24-hour drainage (ml)
508
±
200 549
±
317
0.350
Total drainage (ml)
515
±
202 587
±
334
0.113
COPD
6 (7.7%)
4 (5.5%)
0.746
Dialysis
2 (2.6%)
3 (4.1%)
0.673
Ejection fraction (
<
40%) 13 (16.7%)
12 (16.4%)
0.856
Urgent surgery
1 (1.3%)
3 (4.1%)
0.353
Emergency surgery
0 (0%)
0 (0%)
1.0
Sternal infection
0 (0%)
1 (1.4%)
0.303
Categorical variables are expressed as number (percentage) and continu-
ous variables as mean
=
SD. BMI
=
body mass index; CABG
=
coronary
artery bypass graft; COPD
=
chronic obstructive pulmonary disease.
