CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 7, August 2012
402
AFRICA
the two groups, respectively. The percentage of patients who
had advanced to stage III chronic disease was almost the same
(18.6 vs 17.9%).
Postoperatively, the mortality was similar for the two groups,
with 1.9% of patients with the metabolic syndrome and 1.6%
without the metabolic syndrome who died during their hospital
stay. The re-exploration rate, percentages of patients with a
permanent stroke, those with renal impairment, those with
long mechanical ventilation periods, and patients who required
rewiring of a dehisced sternum were similar in the two groups.
Even if the total number of patients with morbidities were
compared (15.9 vs 12.3%;
p
=
0.1271) the outcome was still
matching.
The mean mediastinal drainage was almost the same in the
two groups (624 and 670 ml, respectively). Homologous blood
transfusion was less in the metabolic syndrome group, with a
mean of 0.4 units per patient compared to the 0.73 units per
patient from the non-metabolic syndrome group (
p
=
0.0012).
Patients from the metabolic syndrome group stayed a mean of
5.9 days (median 5) and those from the non-metabolic syndrome
group 5.8 days (median 5). This difference reached a
p
-value of
<
0.0001 and therefore the metabolic syndrome patients had a
more prolonged hospital stay.
Discussion
Themetabolic syndrome increases the risk of developing coronary
heart disease. In the Atherosclerosis Risk in Communities study,
23% of the 12 000 patients had the metabolic syndrome without
diabetes mellitus and existing cardiovascular disease. Over an
average of 11 years, the men were 1.5 times and women twice as
likely to develop coronary artery disease.
20
The impact of the metabolic syndrome on the population
was also addressed by Shaista Malik. In a cohort of 6 255 adult
patients representing 16 million North Americans, 26% had the
metabolic syndrome. The metabolic syndrome strongly predicted
coronary heart disease, cardiovascular disease and all-cause
mortality and more so than the individual components of the
syndrome.
21
For this study both the ATP III and IDF (2005) criteria were
used. Since the completion of this series, the IDF has adapted its
criteria. Central obesity is no longer an obligatory component,
but it is one of five criteria, of which three constitute diagnosis
of the metabolic syndrome.
22
Central obesity is defined by waist
circumference, but this is gender and ethnicity specific. Waist
circumference was not available in our population but body
weight and height were, from which the BMI could be derived.
With a BMI of
≥
30 kg/m
2
, 85% of men would have had a waist
circumference of at least 102 cm and 98% of women a waist
circumference of 88 cm and more.
23
Patients without the metabolic syndrome might still have
some of the components of the metabolic syndrome, of which
each one is a risk factor for coronary artery disease. In the
Framingham Heart study it was the triad of central obesity,
hypertension and diabetes mellitus which had the highest risk for
cardiovascular disease and mortality.
24
Of those patients without
the metabolic syndrome, 319 could be identified without a BMI
≥
30 kg/m
2
, hypertension or diabetes mellitus. However, they
could still have had dyslipidaemia. Even so, in this so-called
‘clean’ group, underlying undiagnosed diabetes mellitus could
have been present.
In a study on the diagnostic value of haemoglobin A
1c
and
fasting plasma glucose levels in CABG patients with undiagnosed
diabetes mellitus, 60% of patients who were initially admitted
TABLE 2: RESULTS OF THE METABOLIC SYNDROMEAND NON-METABOLIC SYNDROME PATIENTS
Metabolic syndrome (
n
=
370)
Non-metabolic syndrome (
n
=
503)
p
-value
Age (mean)
59.2
59 median
60.4
61 median
0.0811
Gender, male:female
292:78
21.1% female
390:113
22.5% female
0.6250
Re-operation
42
11.4%
52
10.3%
0.6331
LVEF
≤
40%
22
5.9%
22
4.4%
0.2940
Main stem
72
19.5%
90
17.9%
0.5562
Bypasses (mean number)
2.63
3 median
2.71
3 median
0.2318
Urgency
250
67.6%
381
75.7%
0.0076
EuroSCORE (mean)
3.26
3 median
3.61
3 median
0.0494
sMDRD ml/min (mean)
76.2
76.1
0.9960
CKD III
69
18.6%
90
17.9%
0.7749
Re-exploration
5
1.4%
15
3.0%
0.1115
Permanent stroke
3
0.8%
3
0.6%
0.7023
Renal impairment
42
11.4%
42
8.3%
0.1017
Ventilation
>
48 hours
10
2.7%
8
1.6%
0.2531
Re-sternal wiring
6
1.6%
5
1.0%
0.5418
Total number of patients with any of the above 5
59
15.9%
62
12.3%
0.1271
Mortality
7
1.9%
8
1.6%
0.7348
Mortality + morbidity
58
16.5%
64
12.7%
0.0938
Mediastinal drainage (ml) (mean)
624
670
0.3420
RBC (units/patient) (mean)
0.4
0 median
0.73
0 median
0.0012
LOS days (mean)
5.9
5 median
5.8
5 median
<
0.0001
LVEF: left ventricular ejection fraction; sMDRD: shortened Modified Diet in Renal Disease; CKD III: chronic kidney disease grade III; LOS: length of
stay; RBC: red blood cells.
