CARDIOVASCULAR JOURNAL OF AFRICA • Volume 25, No 2, March/April 2014
68
AFRICA
kg unfractionated heparin sulphate.
Blood samples were collected for baseline evaluation
in both groups from the coronary sinus via a retrograde
cardioplegia cannula just before aortic cross clamping (ACC).
Blood cardioplegia solutions at 20°C were delivered for initial
cardioplegia in both antegrade and retrograde manner. Topical
hypothermia was maintained with 1 000 ml of 4°C saline
with induction of cardioplegia in patients in group I only.
Maintenance cardioplegia (22°C blood cardioplegia solution)
was delivered from the antegrade cannula at 20-minute intervals
without topical cooling in both groups.
Blood samples were collected again from the coronary sinus
for evaluation of ischaemia just before maintenance cardioplegia
was delivered in both groups. Blood cardioplegia solutions at
32°C were delivered after completion of the distal anastomosis,
and then the ACC was removed. Topical myocardial rewarming
was provided with 36°C saline in group I patients. Spontaneous
defibrillation, dysrhythmias, and the necessity for defibrillation
and pacemaker implantation were recorded at this time.
The last blood samples for evaluation of reperfusion were
collected inside the retrograde cannula in both groups, and then
CPB was stopped after the body temperature reached 36°C.
After neutralisation of anticoagulation, standard procedures
such as control of bleeding, placing of pacemaker wires, and
insertion of drainage tubes were performed. The operation was
terminated with standard surgical techniques and the patients
were transported to the intensive care unit (ICU).
Maximum care was taken to avoid phrenic nerve injury
during LIMA harvesting. The first intercostal artery was
devascularised with haemostatic clips without cauterisation.
Partial pericardiotomy was avoided as far as possible to prevent
phrenic nerve injury. Patients who underwent cauterisation or
partial pericardiotomy despite these protective methods were
also recorded. Standard surgical procedures prevailed throughout
the study.
Routine pre-operative examinations were done. Echo-
cardiographic evaluation was performed on all patients
pre-operatively and just before discharge by the same cardiologist
who was blinded to the patient population. Electrocardiograms
were taken with the same device pre-operatively, at the 24th hour
postoperatively and just before discharge.
Troponin I (TnI), troponin T (TnT), myoglobin, CK-MB
and lactate dehydrogenase (LDH) levels were assayed from
blood samples, which were collected from the peripheral
venous system pre-operatively and at the eighth and 24th
hours of ACC. CK-MB and LDH levels were measured
with spectrophotometric methods using an Olympus AU640
(Shizuoka-ken, Japan) device, myoglobin and TnI levels were
measured using chemiluminescence on a Backman Coulter
Access II (Fullerton CA, USA) device, and TnT levels were
measured with electrochemiluminescence methods on a Roche
Elecys 2010 (Tokyo, Japan) device.
Thoracic X-rays were taken from the same machine (AMX-4
plus, General Electric Company, NWL Bordentown NJ, USA),
at the same distance, with the same dosage for individual
patients and with the same technician pre-operatively, 48 hours
postoperatively and before discharge. Diaphragm levels, pleural
effusions and other possible complications were recorded.
TnI, TnT, myoglobin, complement 3 (C3), C4 and TNF-
α
levels were examined from blood samples, which were taken
from the coronary sinus via the retrograde cardioplegia cannula
for basal, ischaemia and reperfusion analysis as mentioned
above. We aimed to determine the cardiac myocyte reserves
directly by analysing myocardial enzymes and complement
factors at different periods of ischaemia. C3 and C4 levels were
measured with nephelometric methods, using Dade Behring BN
II kits (Siemens, Germany), and TNF-
α
levels were measured
with Elisa methods, using the Human TNF-alpha instant ELISA
kits (e Bioscience, USA).
Other parameters such as ACC time, total CPB time,
cardioplegia amounts, number of proximal anddistal anastomoses,
necessity for defibrillation and pacemaker placement, and
necessity for IABP and/or positive inotropic agents were
recorded. Endotracheal intubation time, ICU length of stay, total
drainage and transfusion amounts, dysrhythmias, necessity for
re-operation, length of hospital stay, and existence of pleural
effusion or diaphragmatic paralysis were also recorded.
The patients were followed up on the first week and first month
of discharge. ECGs were evaluated by the same cardiologist who
was unaware of the patient population. New development of
ischaemia-specific changes, such as ST-segment elevations, Q
waves, Pardee waves and bundle branch blocks on ECG were
seen as abnormal changes in myocardial function, while negative
T waves were seen as pericardial reactions.
The X-rays of patients were evaluated by a radiologist who
was blinded to the patient population. Necessity for drainage and
amounts of pleural effusions, diaphragm paralysis and elevations
were recorded. Diaphragm changes above two or more ribs were
determined as a positive result, according to the current literature
data.
3
Positive echocardiographic changes were determined
as follows: new development of valve disorders, structural
or transactional changes of the ventricular wall, aneurysm
formation and a decrease in EF of more than 10%.
In addition, haemodynamic parameters, respiratory
parameters, blood gas levels, drainage amounts, muscle strength
and body temperature were recorded for decisions on extubation
time. Intubation time was recorded from the first intubation point
in the operating room to the extubation point in ICU. All patients
were discharged from ICU to clinical service after removal
of their drainage tubes. Operative mortality was evaluated as
mortality within the first 30 days.
Statistical analysis
This was performed with the package program SPSS for
Windows 15.0. Chi-square and Fisher’s exact tests were used for
comparisons of qualitative data for both groups, and the
t
-test
was used for comparisons of quantitative data of free samples.
The paired
t
-test was used for quantitative data analysis of time-
dependent changes. Assessment of time-dependent changes of
inter-group differences was done with two-way ANOVA for
repeated measurements.
Frequency and percentage data were used as a descriptive
value for qualitative data, and arithmetic mean
±
standard
deviation as quantitative data. A
p
-value
<
0.05 was considered
statistically significant.
Results
Fifty patients (42 male and eight female) were included in this
