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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 28, No 1, January/February 2017
32
AFRICA
the independent predictors of MACE. All variables showing
significance values (
p
<
0.05) on univariate analysis were included
in the multivariate model. The association between variables
was tested using Spearman’s or Pearson’s correlation coefficient.
Two-tailed
p
-values
<
0.05 were considered significant and the
confidence interval (CI) was 95%. All statistical analyses were
conducted using the Statistical Package for Social Sciences
(SPSS) program (version 15.0, SPSS, Chicago, Illinois, USA).
Results
Pre-operative patient characteristics for the ONBHCAB and
OPCAB groups before and after matching are listed in Table
1. Peri-operative and early postoperative characteristics of the
propensity-matched patients are shown in Table 2.
The average number of distal anastomoses per patient was
significantly higher in the ONBHCAB group (
p
<
0.001). The
OPCAB group showed fewer grafted LAD and Cx territories
(
p
<
0.001,
p
=
0.003, respectively). However, there was no
significant difference between the groups in terms of incomplete
revascularisation rate.
Mean duration of CPBwas 70
±
35 minutes in the ONBHCAB
group. OPCAB was associated with significantly shorter mean
ventilation times (
p
<
0.001), mean lengths of intensive care
unit stay (
p
<
0.001) and duration of hospital stay (
p
<
0.001).
The total blood loss was significantly more in the ONBHCAB
group (
p
<
0.001). Accordingly, the mean number of transfused
RBC units was significantly lower in the OPCAB group (
p
<
0.001). Renal complications were significantly higher in the
ONBHCAB group (
p
=
0.004). Postoperative characteristics
of the groups were similar regarding early re-operation and
rehospitalisation, in-hospital mortality rates, mediastinitis,
pulmonary and neurological complications, peri-operative atrial
fibrillation (AF) frequency, peri-operative MI, and the need for
inotropic or IABP support.
Table 1. Baseline characteristics of the study groups
Overall
(
n
=
760)
Propensity-matched patients
(
n
=
398)
Charac-
teristics
ONBHCAB
(
n
=
327)
OPCAB
(
n
=
433)
p
-value
ONBHCAB
(
n
=
181)
OPCAB
(
n
=
217)
p
-value
Age
(years)
63.37
±
9.65 59.7
±
9.08
<
0.001 61.17
±
9.02 60.16
±
8.8 0.3
Males
255 (78)
359 (82.9)
0.08 147 (81.2)
179 (82.5)
0.74
Euroscore 3.9
±
2.41 2.79
±
1.99
<
0.001 3.06
±
2.13 2.83
±
2.1 0.17
Obesity
(BMI
≥
30
kg/m
2
)
93 (28.4)
80 (18.5)
0.001 53 (29.3)
48 (22.1)
0.1
Current
smoker
142 (43.4)
234 (54)
0.004 85 (47)
113 (52.1)
0.31
Hyperten-
sion
172 (52.6)
245 (56.6)
0.27 95 (52.5)
126 (58.1)
0.26
Dyslipi-
daemia
114 (34.9)
181 (41.8)
0.05 62 (34.3)
89 (41)
0.16
Diabetes
mellitus
102 (31.2)
125 (28.9)
0.48
58 (32)
64 (29.5)
0.58
NIDDM 74 (22.6)
98 (22.6)
0.99 44 (24.3)
46 (21.2)
0.46
IDDM 28 (8.6)
27 (6.2)
0.22 14 (7.7)
18 (8.3)
0.83
USAP
97 (29.7)
138 (31.9)
0.51 46 (25.4)
74 (34.1)
0.6
COPD 36 (11)
12 (2.8)
<
0.001 14 (7.7)
9 (4.1)
0.12
CrCl
103.3
±
34.13 101.06
±
38.9 0.04 102.35
±
40.6 101.19
±
30.58 0.21
Stroke
7 (2.1)
14 (3.2)
0.36
4 (2.2)
7 (3.2)
0.54
TIA
7 (2.1)
8 (1.8)
0.77
4 (2.2)
4 (1.8)
0.79
Peripheral
vascular
disease
65 (19.9)
30 (6.9)
<
0.001 29 (16)
25 (11.5)
0.19
History
of MI
127 (38.8)
189 (43.6)
0.18 53 (29.3)
81 (37.3)
0.91
Normal
LV
function
213 (65.1)
316 (73)
0.02 129 (71.3)
162 (74.7)
0.45
Impaired
LV
function
114 (34.9)
117 (27)
0.02 52 (28.7)
55 (25.3)
0.45
Moderate
LV
function
96 (29.4)
104 (24)
0.09 44 (24.3)
49 (22.6)
0.68
Poor LV
function
18 (5.5)
13 (3)
0.08
8 (4.4)
6 (2.8)
0.37
Previous
PCI
37 (11.3)
16 (3.7)
<
0.001 15 (8.3)
9 (4.1)
0.54
Number
of
diseased
vesssels
2.69
±
0.56 2.62
±
0.54 0.01 2.69
±
0.56 2.64
±
0.53 0.12
LMCA 59 (18)
45 (10.4)
0.002 30 (16.6)
24 (11.1)
0.11
Three-
vessel
disease
246 (75.2)
285 (65.8) 0.005 135 (74.6)
146 (67.3)
0.12
*Statistically significant difference. Values are presented as mean
±
standard deviation
or number (%), where appropriate.
BMI, body mass index; CrCL, creatinine clearance; CAD, coronary artery disease;
COPD, chronic obstructive pulmonary disease; IDDM, insulin-dependent diabetes
mellitus; LMCA, left main coronary artery; LV, left ventricle MI, myocardial infarc-
tion; NIDDM, non-insulin-dependent diabetes mellitus; ONBHCAB, on-pump beat-
ing heart coronary artery bypass surgery; OPCAB, off-pump coronary artery bypass
surgery; PCI, percutaneous coronary intervention; PVD, peripheral vascular disease;
TIA, transient ischaemic attack; USAP, unstable angina pectoris.
Table 2. Operative and early postoperative characteristics of the
propensity matched patients
Characteristics
ONBHCAB
(
n
=
181)
OPCAB
(
n
=
217)
p
-value
Number of distal anastomoses
3.44
±
0.85 2.84
±
0.81
<
0.001*
Incomplete revascularisation
41 (22.7)
55 (25.3)
0.53
Grafted coronary artery
LAD
1.64
±
0.5 1.39
±
0.55
<
0.001*
Cx
0.96
±
0.58 0.71
±
0.56 0.003*
RCA
0.82
±
0.58 0.79
±
0.59 0.05
CPB time (min)
70
±
35
Duration of ventilation (h)
11.28
±
38.7 5.97
±
4.01
<
0.001*
Duration in intensive care unit (h)
28.27
±
63.9 25.48
±
36.1
<
0.001*
Total blood loss (ml)
507.6
±
296.8 341.9
±
190.4
<
0.001*
RBC (unit)
1.17
±
1.57 0.2
±
0.58
<
0.001*
Peri-operative inotropic agent
8 (4.4)
6 (2.8)
0.37
Peri-operative IABP required
4 (2.2)
2 (0.9)
0.29
Peri-operative MI
11 (6.1)
13 (6)
0.97
Peri-operative AF
21 (11.6)
28 (12.9)
0.69
Neurological complication
11 (6.1)
6 (2.8)
0.10
Encephalopathy
4 (2.2)
1 (0.5)
0.11
TIA
6 (3.3)
4 (1.8)
0.35
Stroke
1 (0.6)
1 (0.5)
0.89
Pulmonary complications
11 (6.1)
7 (3.2)
0.17
Renal complications
24 (13.3)
11 (5.1)
0.004*
Mediastinitis
2 (1.1)
1 (0.5)
0.95
Duration of hospital stay (days)
5.96
±
3.51 5.41
±
4.38
<
0.001*
Early re-operation
5 (2.8)
3 (1.4)
0.33
Early rehospitalisation (
<
30 days)
13 (7.2)
14 (6.5)
0.92
Hospital mortality (
<
30 days)
3 (1.7)
6 (2.8)
0.46
*Statistically significant difference. Values are presented as mean
±
standard
deviation or number (%), where appropriate.
AF, atrial fibrillation; LAD, left anterior descending artery; Cx, circumflex
coronary artery; IABP, intra-aortic balloon pump; MI, myocardial infarction;
ONBHCAB, on-pump beating heart coronary artery bypass surgery; OPCAB,
off-pump coronary artery bypass surgery; RBC, red blood cell; RCA, right
coronary artery; TIA, transient ischaemic attack.