CARDIOVASCULAR JOURNAL OF AFRICA • Vol 24, No 6, July 2013
214
AFRICA
dipyridamole or anticoagulant use, those that had a coagulation
or platelet dysfunction, and cases having simultaneous valve
surgery, aortic surgery, ventricular aneurism resection or carotid
endarterectomy were also excluded from this study. Cases in
whom stenosis of the carotid artery was considered critical were
excluded. Patients who had undergone re-operation were also
excluded.
Patients older than 60 years of age, those with a history
of stroke or transient ischaemic attack before the operation,
and cases in whom a systolic murmur was detected over the
carotid artery were all routinely examined by carotid Doppler
ultrasonography.
The development of neurological deficits and strokes in
the 30-day post-operative period, and the association of this
clinical situation with mortality was assessed. These cases were
followed up in co-operation with a neurologist. Cranial magnetic
resonance imaging and computerised tomography were used in
the diagnosis.
Midalozam 5 mg was administered intramuscularly to all
patients one hour before the intervention as pre-medication.
Cefazolin 1 g was administered intravenously before induction
of anaesthesia and continued in repeated doses (twice a day)
until chest tube removal. In case of infection, a swab was taken
from the wound and following the outcome of cultures, targeted
antibiotics were administered.
Internal thoracic artery (ITA) and saphenous vein grafts
were prepared after median sternotomy. Cardiopulmonary
bypass was started with arterial cannulation of the ascending
aorta and two-stage venous cannulation from the right atrial
auricle. Non-pulsatile extra-corporeal circulation (ECC)
(cardiopulmonary bypass) was started with a Sarns roller pump
(Sarns, Fort Myers, FL,USA) at 2.4–2.6 l/m
2
/min, and mild–
moderate hypothermia (oesophageal temperature 26–28°C) was
obtained. A membrane oxygenator (Dideco, Mirandola, Italy)
was used for oxygenation during ECC.
The haematocrit values were kept between 20 and 25%,
and mean perfusion pressure measured from the radial artery
was kept between 50 and 80 mmHg during bypass. Multi-dose
antegrade blood cardioplegia was used in both groups.
Before placement of the cross clamping, the arterial pressure
was lowered to 30 mmHg for a few seconds in a controlled
fashion with ECC support, and the aorta was evaluated manually
in detail. Partial clamping was not used in patients in whom the
presence of plaques in the aorta was suspected. For patients in
whom no atherosclerotic plaques were found in the aorta, it was
clamped at the aortic root.
Cardiac arrest was obtained by applying 1 500 ml isothermic
blood cardioplegic solution antegradely from the aortic root, and
topical cold saline was applied in all patients. Blood cardioplegic
solution doses for maintenance were administered consequently.
Cardioplegic solution at 37ºC, with the heater circulatory
system in the cardioplegia set (Dideco, Mirandola, Italy), was
administered to obtain a controlled reperfusion before the cross
clamp was removed in both groups.
All of the proximal anastomoses were done with an aortic
partial clamp in group 1. The clamp was removed when the last
proximal anastomosis was completed, before the suture material
was tied; bleeding of the aorta for at least 10 seconds was
permitted before tying.
In group 2, each patient was warmed while the proximal
anastomoses were performed. The proximal anastomoses were
done under cross clamping in the resting heart. The sutures were
not tied after the last proximal anastomosis, and bleeding of the
aorta was permitted for at least 10 seconds in this region after the
clamp was removed. The patients were kept under observation
in the intensive care unit for at least six hours with mechanical
respiratory support.
Statistical analysis
The results are presented as mean
±
standard deviation. The
data were evaluated with multivariate logistic analysis, Student’s
t
-test and chi-square test. In all studies,
p
-values
<
0.05 were
considered statistically significant.
Results
There were no statistically significant differences between
the two groups in terms of mean age, gender, morbid obesity,
smoking habit, hypertension, diabetes mellitus, and chronic
pulmonary or renal disease (
p
>
0.05). There were also no
significant differences in terms of functional capacity according
to New York Heart Association (NYHA) classification, blood
cholesterol level, family history, accompanying peripheral artery
disease and history of cerebrovascular disease (
p
>
0.05). The
mean ejection fraction (EF) values of the patients at pre-operative
echocardiographic evaluation were 45.4
±
5.23 in group 1 and
46.4
±
2.31 in group 2, and the difference was not statistically
significant (
p
=
0.067). Comparisons of the demographic data of
the patients are summarised in Table 1.
The operative data of the patients, such as time of cross
clamp, time of perfusion, mean number of distal anastomoses,
inotropic agent support, amount of post-operative drainage,
intra-aortic balloon use, peri-operative myocardial infarction,
duration of intubation, duration of stay in the intensive care unit
(ICU), and post-operative complications were compared. The
results of these comparisons are summarised in Table 2.
Post-operative stroke was seen in 26 patients in group
1 (1.73%), and in nine patients in group 2 (1.8%). The
difference was not statistically significant (
p
=
0.92). All
patients who suffered from stroke were older than 55 years.
In a detailed analysis of the group of patients with stroke, the
frequency of smoking was 24%, diabetes 67%, hypertension
72%, atrial fibrillation 35%, peripheral arterial disease 74%, and
hypercholesterolaemia 68%. Echocardiographic left ventricular
ejection fraction (LVEF) was lower than 45% in all patients
(Table 3).
A total of 31 patients [24 patients from group 1 (1.6%) and
seven patients from group 2 (1.4%)] were lost during the 30-day
post-operative period due to multiple organ failure that had
developed after low cardiac output. The difference between the
groups was not significant (
p
=
0.91). The 30-day mortality rate
in all patients included in this study was 1.55% (31 patients).
The mean duration of stay in hospital was 5.1
±
2.8 days in
group 1 and 4.9
±
3.6 days in group 2, and the difference was
not significant (
p
=
0.46).
Discussion
Major neurological problems are among the most feared
complications after CABG with cardio-pulmonary bypass.
