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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 26, No 4, July/August 2015
AFRICA
161
for the difference in number of grafts and hospital stay, patient
demographic and peri-operative characteristics were similar in
the two groups (Table 1).
For pre-operative values of the leukocyte screen, the two
groups were similar in terms of leukocyte, neutrophil and
lymphocyte counts and N:L ratios (Table 2). However, comparing
systemic leukocyte counts affected by the surgical stress of
CABG alone, with pre-operative values, a significant increase
in counts of total leukocytes and neutrophils, and N:L ratio,
and a decrease in lymphocyte counts was found on the first and
fifth days after surgery, regardless of the technique used (with or
without CPB) (Table 2).
Regarding intergroup comparison of values, on the first
post-operative day, there was a statistically significant difference
between the two groups in terms of absolute lymphocyte counts
(0.84
±
0.92 in group I and 1.12
±
0.73 in group II,
p
<
0.001). The
N:L ratio was also significantly different between the two groups
(20.73
±
13.85 in group I and 10.19
±
4.55 in group II,
p
<
0.001).
On the fifth postoperative day, there were no statistically
significant differences in absolute numbers of lymphocytes or N:L
ratios between the two groups. There were however statistically
significant differences between the two groups in terms of
absolute numbers of total leukocytes (12.23
±
4.75 in group I and
9.38
±
2.23 in group II,
p
=
0.002) and neutrophils (9.27
±
4.78 in
group I and 5.97
±
1.86 in group II,
p
<
0.001) (Table 2).
Regarding the change in total leukocyte, neutrophil and
lymphocyte counts, and N:L ratios on the first and fifth
postoperative days, from baseline values before the operation,
we observed significant intergroup differences on the first
postoperative day only (Table 3). There was a significant
decrease in lymphocyte counts in group I (52.70
±
70.83)
compared to group II (49.40
±
18.79) (
p
=
0.003), and a larger
increase in N:L ratios in group I (1031.78
±
950.53) compared to
group II (472.15
±
415.93) (
p
=
0.001). The change in other values
(total leukocyte and neutrophil counts) were similar in the two
groups on the first postoperative day. The change in all counts
on the fifth postoperative day was not significantly different in
the two groups (Table 3).
Discussion
Surgical stress, regardlessof the typeof surgery, suppresses cellular
immunity as a result of the host’s inflammatory responses. This
suppression may be deleterious to the host’s defense mechanisms,
along with overproduction of inflammatory mediators.
11
Some
morbidity parameters such as postoperative infection could be
predicted from a significant increase in neutrophil and a decrease
in lymphocyte counts.
12
In many previous studies, morbidity and mortality of patients
with cardiovascular disease have been demonstrated to be
Table 2. Comparison of values at all time
points between the two groups
Group I
(
n
=
30)
Group II
(
n
=
30)
p
-value
Pre-operative
Total leucocytes (10
3
/ml)
7.59
±
1.78
7.07
±
1.55
0.403
Neutrophils (10
3
/ml)
4.19
±
1.07
4.19
±
0.97
0.604
Lymphocytes (10
3
/ml)
2.18
±
0.72
2.25
±
0.95
0.609
N:L ratio
2.10
±
0.70
2.07
±
0.76
0.745
Postoperative 1st day
Total leucocytes (10
3
/ml)
13.11
±
3.94
*
12.67
±
4.60
*
0.464
Neutrophils (10
3
/ml)
11.46
±
3.54
*
9.93
±
4.14
*
0.078
Lymphocytes (10
3
/ml)
0.84
±
0.92
*
1.12
±
0.73
*
<
0.001
**
N:L ratio
20.73
±
13.85
*
10.19
±
4.55
*
<
0.001
**
Postoperative 5th day
Total leucocytes (10
3
/ml)
12.23
±
4.75
*
9.38
±
2.23
*
0.002
**
Neutrophils (10
3
/ml)
9.27
±
4.78
*
5.97
±
1.86
*
<
0.001
**
Lymphocytes (10
3
/ml)
1.73
±
0.64
*
1.76
±
0.71
*
0.959
N:L ratio
6.15
±
3.86
*
3.71
±
1.31
*
0.006
Values are mean (
±
standard deviation) or median (range) as appropriate.
*
p
<
0.05 compared with pre-operative values within the groups.
**
p
<
0.05 compared between groups.
Group I: group with cardiopumonary bypass, Group II: group with off-
pump coronary artery bypass, N:L: neutrophil:lymphocyte ratio.
Table 1. Demographic and peri-operative
clinical data of the patients
Group I
(
n
=
30)
Group II
(
n
=
30)
p-
value
Males,
n
(%)
20 (66.7)
15 (50.0)
0.190
Age (years)
63.73
±
10.49 68.10
±
6.98 0.102
DM,
n
(%)
14 (46.7)
12 (40.0)
0.602
Smoking,
n
(%)
16 (53.3)
14 (46.7)
0.606
Hypertension,
n
(%)
11 (36.7)
17 (56.7)
0.121
USAP,
n
(%)
2 (6.7)
4 (13.3)
0.671
Previous PTCA,
n
(%)
3 (10.0)
9 (30.0)
0.053
Pre-operative EF (%)
49.73
±
10.45 49.63
±
12.60 0.982
LMCA disease,
n
(%)
2 (6.7)
0 (0.0)
0.492
No of grafts
3.20
±
0.88 1.93
±
0.78
<
0.001
Postoperative inotropic need,
n
(%)
12 (40.0)
11 (36.7)
0.791
Postoperative IABCP need,
n
(%)
6 (20.0)
1 (3.3)
0.103
Postoperative MI,
n
(%)
2 (6.7)
0 (0.0)
0.492
Postoperative dysrhythmia,
n
(%)
8 (26.7)
11 (36.7)
0.405
Mechanichal ventilation time
(hrs) 5.73
±
2.70 5.30
±
1.53 0.897
ICU stay (days)
1.87
±
0.68 1.83
±
1.20 0.256
Hospital stay (days)
8.97
±
2.39 5.90
±
2.07
<
0.001
Values are mean (
±
standard deviation) or median (range) as appropriate
.
Group I: group with cardiopumonary bypass, group II: group with off-
pump coronary artery bypass, DM: diabetes mellitus, USAP: unstable
angina pectoris, IABCP: intra-aortic balloon counterpulsation, ICU:
intensive care unit, PTCA: percutaneous transluminal coronary angio-
plasty, EF: ejection fraction, LMCA: left main coronary artery, MI:
myocardial infarction.
Table 3. Change in values on the first and fifth postoperative days
compared with pre-operative values in the two groups
Group I (
n
=
30) Group II (
n
=
30)
p
-value
Postoperative 1st day
Total leucocytes (10
3
/ml)
(83.49
±
74.82)
↑
(77.70
±
42.09)
↑
0.802
Neutrophils (10
3
/ml)
(191.16
±
123.34)
↑
(142.43
±
89.60)
↑
0.133
Lymphocytes (10
3
/ml)
(52.70
±
70.83)
↓
(49.40
±
18.79)
↓
0.003
*
N:L ratio
(1031.78
±
950.53)
↑
(472.15
±
415.93)
↑
0.001
*
Postoperative 5th day
Total leucocytes (10
3
/ml)
(70.86
±
79.84)
↑
(39.14
±
45.56)
↑
0.154
Neutrophils (10
3
/ml)
(138.00
±
140.63)
↑
(48,91
±
55.02)
↑
0.005*
Lymphocytes (10
3
/ml)
(11.86
±
46.51)
↓
(10.63
±
42.38)
↓
0.442
N:L ratio
(217.94
±
207.83)
↑
(102.74
±
110.49)
↑
0.013*
Values are mean percent (
±
standard deviation) or median percent (range) as
appropriate. *
p
<
0.05 compared between groups.
Group I: group with cardiopumonary bypass, group II: group with off-pump
coronary artery bypass, N:L: neutrophil:lymphocyte,
↑
: increase,
↓
: decrease
from pre-operative values.