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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 28, No 1, January/February 2017
50
AFRICA
Results
There were 109 males and 43 females with a mean age of 60.1
±
8.6 years (range 39–85 years). According to the NCEP ATP
III criteria,
3
64 patients (42%) had the MS, while the remaining
88 (58%) were free of the MS. The two groups were similar
with regard to age and gender. All the MS parameters (BMI,
waist circumference, rates of hyperlipidaemia, hypertension and
diabetes) were significantly higher in the MS group.
Pre-operative demographic features and operative data for
each study group are shown in Table 2. When compared with
patients without the MS, those with the MS had higher levels
of fasting glycaemia, postprandial glycaemia, plasma total
cholesterol, triglycerides and LDL-C, and a lower HDL-C
concentration. Laboratory findings of the two patient groups
are shown in Table 3. Overall, 102 patients (67.2%) had diabetes.
Medications of the diabetic patients included oral anti-diabetic
agents (58.8%), insulin (18.6%) or both (10.8%), while 11.8% had
been receiving no diabetes treatment.
Postoperative clinical outcomes are shown in Table 4.
Postoperative mortality rates were similar in the two groups,
being 3.1% (
n
=
2) and 1.1% (
n
=
1) in patients with and without
the MS, respectively. However, manifestations of postoperative
morbidity differed significantly, with higher rates of atrial
fibrillation (AF), wound infection, pulmonary complications,
prolonged intubation, and longer durations of ICU stay and
hospitalisation in patients with the MS (
p
<
0.01). The other peri-
and postoperative findings (postoperative revisions, incidences of
renal impairment, stroke, drainage, need for erythrocytes, fresh
frozen plasma replacements, cardiopulmonary bypass time and
aortic cross-clamp time) were similar between the two groups.
A statistically significant relationship was found between
the MS and wound infection (OR 6.64, 95% CI: 1.72–25.75),
pulmonary complications (OR 6.44, 95% CI: 1.58–26.33), AF (OR
5.47, 95% CI: 1.50–19.97) and prolonged intubation (OR 1.17,
95% CI: 1.05–1.32). In
post hoc
power analysis, the observed power
for wound infection, pulmonary complications, AF and prolonged
intubation time were 0.944, 0.804, 0.843 and 0.715, respectively.
Discussion
As MS patients have a high risk of developing coronary
artery disease, they should be evaluated in line with coronary
Table 2. Comparison of pre-operative demographic and peri-operative
data of patients with and without the metabolic syndrome
MS (+)
(
n
=
64)
MS (
–
)
(
n
=
88)
p
-value
Age (mean
±
SD)
59.98
±
6.89 60.55
±
9.74
a
0.678
Gender,
n
(%)
Male
44 (68.8)
65 (73.9)
c
0,611
Female
20 (31.3)
23 (26.1)
BMI (kg/m²) (mean
±
SD)
31.09
±
5.56 27.58
±
3.34
a
0.001**
Waist circumference (mean
±
SD)
Total
106.92
±
10.30 93.69
±
8.21
a
0.001**
Female
108.86
±
9.18 95.11
±
7.77
a
0.001**
Male
102.65
±
11.54 89.65
±
8.25
a
0.001**
Smoking,
n
(%)
32 (50.0)
40 (45.5)
d
0.579
Alcohol consumption,
n
(%)
11 (17.2)
15 (17.0)
c
1.000
Hyperlipidaemia,
n
(%)
41 (64.1)
31 (35.2)
c
0.001**
Hypertension,
n
(%)
57 (89.1)
11 (12.5)
c
0.001**
Carotid Doppler USG (50 and 70%),
n
(%)
16 (25.0)
11 (12.5)
d
0.076
EF% (mean
±
SD)
51.25
±
9.21 52.52
±
10.67
a
0.433
EuroSCORE (min–max/median)
0–9/4
0–11/4
b
0.391
Number of grafts (mean
±
SD)
3.05
±
0.93 3.07
±
0.84
a
0.883
CPB (min) (mean
±
SD)
74.09
±
16.70 71.90
±
19.82
a
0.174
Aortic cross-clamp time
(min) (mean
±
SD)
51.08
±
14.76 47.28
±
17.84
a
0.225
a
Student’s
t
-test;
b
Mann–Whitney
U
-Test;
c
Yates continuity correction test;
d
Pearson’s chi-squared test *
p
<
0.05 **
p
<
0.01.
BMI: body mass index, EF: ejection fraction, CPB: cardiopulmonary bypass
(presence of the MS was significantly associated with higher prevalence).
Table 3. Comparison of laboratory findings of the patients
with and without the metabolic syndrome
MS (+)
(
n
=
64)
MS (
–
)
(
n
=
88)
p
-value
FBG (mg/dl) (min–max/median) 79–300/151.00 77–300/110.00
b
0.001**
PPBG (mg/dl) (mean
±
SD)
191.84
±
51.09 157.06
±
53.04
a
0.001**
BUN (mg/dl) (mean
±
SD)
18.25
±
5.93 17.53
±
5.66
a
0.447
Creatinine (mg/dl)(mean
±
SD)
0.95
±
0.26
0.96
±
0.25
a
0.775
AST (U/l) (min–max/median)
12–62/25.00 11–51/24.00
b
0.490
ALT (U/l) (min–max/median)
10–97/28.00
8–61/22.00
b
0.241
Total cholesterol (mg/dl)
(mean
±
SD) (mmol/l)
226.95
±
34.18
(2.56
±
0.89)
185.69
±
36.08
(4.81
±
0.93)
a
0.001**
LDL-C (mg/dl) (mean
±
SD)
(mmol/l)
134.92
±
21.80
(3.49
±
0.56)
121.89
±
25.04
(3.16
±
0.65)
a
0.001**
HDL-C (mg/dl) (mean
±
SD)
(mmol/l)
36.22
±
9.21
(0.94
±
0.24)
38.77
±
7.95
(1.00
±
0.21)
a
0.069
Triglycerides (mg/dl) (min–max/
median) (mmol/l)
71–465/160.00
(0.8–5.25/1.81)
57–482/138.00
(0.64–5.45/1.56)
b
0.049*
Haematocrit (%) (mean
±
SD)
39.90
±
4.35 41.13
±
4.57
a
0.098
Haemoglobin (g/dl) (mean
±
SD)
13.32
±
1.62 14.01
±
1.60
a
0.010*
TSH (µIU/ml) (min–max/median) 0.01–11.34/1.45 0.12–19.00/1.41
b
0.621
Free T
4
(ng/dl) (mean
±
SD)
1.26
±
0.22
1.20
±
0.19
a
0.071
HbA
1c
(%)
7.86
±
1.59
6.61
±
1.31
a
0.001**
a
Student’s
t
-test;
b
Mann–Whitney
U
-test *
p
<
0.05 **
p
<
0.01.
FBG: fasting blood glucose, PPBG: postprandial blood glucose, BUN: blood
urea nitrogen, ALT: alanine aminotransferase, AST: aspartate aminotransferase,
LDL-C: low-density lipoprotein cholesterol, HDL-C: high-density lipoprotein
cholesterol, TSH: thyroid-stimulating hormone, HbA
1c
: haemoglobin A
1c
.
Table 4. Comparison of postoperative results of the
patients with and without the metabolic syndrome
MS (+)
(
n
=
64)
MS (–)
(
n
=
88)
p
-value
Prolo
nged intubation time (h)
(min–max/median)
6–20/11.00
4–28/9.00
b
0.001**
Drainage (ml) (min–max/
median)
400–2500/650.00 200–1500/ 650.00
b
0.135
Length of
ICU
stay
(h)
(min–max/median)
17–168/24.00
6–96/22.00
b
0.003**
Length of hospital stay (days)
(min–max/median)
4–35/7.00
1–35/7.00
b
0.001**
RBC replacement (units/
patient) (min–max/median)
0–5/2.00
0–5/2.00
b
0.121
FFP replacement (units/
patient) (min–max/median)
0–6/2.00
0–12/2.00
b
0.153
Mortality,
n
(%)
2 (3.1)
1 (1.1)
e
0.573
Myocardial infarction,
n
(%)
4 (6.3)
1 (1.1)
e
0.162
Surgical revision,
n
(%)
5 (7.8)
5 (5.7)
e
0.743
Renal failure,
n
(%)
4 (6.3)
1 (1.1)
e
0.162
Wound infection,
n
(%)
14 (21.9)
3 (3.4)
c
0.001**
Pulmonary complications,
n
(%)
11 (17.2)
3 (3.4)
c
0.009**
Stroke,
n
(%)
4 (6.3)
1 (1.1)
e
0.162
Atrial fibrillation,
n
(%)
13 (20.3)
4 (4.5)
c
0.005**
b
Mann–Whitney
U-
Test;
c
Yates continuity correction test;
e
Fisher’s exact test;
*
p
<
0.05; **
p
<
0.01.
RBC: red blood cells, FFP: fresh frozen plasma.