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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 31, No 6, November/December 2020
AFRICA
323
catecholaminergic stress in the post-ACS phase, particularly
in relation to the extent of the infarction and the relative
alteration of LVEF.
19
Evidence of a reduced mortality rate after
lowering blood glucose levels on insulin therapy argues against
blood glucose as a simple epiphenomenon of the stress state.
20
Hyperglycaemia is associated with insulin resistance, increased
levels of free fatty acids,
21
marked inflammatory response,
and endothelial and microvascular dysfunction, leading to
myocardial cell vulnerability, ischaemia and hypoxia.
22,23
This
may explain why in our study, patients with blood glucose > 140
mg/dl (7.8 mmol/l) had higher peaks of troponin Ic and cardiac
enzymes. Recently, a new concept, glycaemic variability, has been
described in a few studies. In patients with acute myocardial
infarction, glycaemic variability was associated with the severity
of CAD
24
and death.
25
Patients with acute hyperglycaemia and without a history of
DM should undergo close follow up and screening for glucose
metabolism disorders.
18
Current recommendations emphasise the
use of OGTT and glycated haemoglobin as screening tests.
26
In a
study conducted in South Africa among patients with CAD, the
rate of IGT measured by OGTT was 30% higher than the rate
of DM (20%).
27
This study included a small sample of patients,
but highlights the need for screening of glucose metabolism
disorders in patients with CAD in our practice.
The other predictors for in-hospital death identified in our
study (age, heart failure, left ventricular dysfunction, sustained
ventricular tachycardia/ventricular fibrillation) are powerful
prognostic factors in ACS patients, consistent with studies in
developed countries.
6
Dyslipidaemia appeared to be a protective
factor, and this observation has already been reported.
28
It is
mainly the influence of previous lipid-lowering drugs in patients
with high cardiovascular risk that would have a beneficial effect
on mortality rate.
28
Previous treatments in our study were not
specified.
PCI was a protective factor in our series but remarkably, only
in patients without a history of DM in sub-group analyses. First,
the low rate of PCI in our patients with ACS
29
is a potential bias.
Second, CAD patients with DM frequently have multi-vessel
coronary heart disease (28.9%) and complex lesions (39.7%),
30
as in studies conducted in developed countries.
31
Coronary
artery bypass graft surgery is often the technique of choice
for complete revascularisation in patients with DM,
32
but is of
limited practice in sub-Saharan Africa. Finally, DM patients
are often high-risk patients in whom an earlier invasive strategy
should be implemented. However, the excessive admission
delays
11
determine the low rate of PCI, which would weaken its
beneficial effect.
Limitations
Our study has some limitations. Incomplete medical records did
not allow us to make a thorough analysis. Glycated haemoglobin
was not available for all patients and was not included in
our analysis, nor was the evolution of blood glucose levels
during hospitalisation. The influence of previous treatments
(antidiabetic drugs, statins) and glucose-lowering treatments
given during hospitalisation (particularly insulin infusion) have
not been specified. Finally, the low rate of coronary angiography
did not make it possible to assess the link between blood glucose
levels and the severity of CAD.
Conclusion
This study, carried out in a sub-Saharan African population,
shows that in the acute phase of ACS, admission blood
glucose has a powerful prognostic value on mortality rate, in
accordance with studies conducted in the West. In association
with conventional treatment of ACS, adequate control of
blood glucose is an important treatment target, especially in
non‐diabetic patients. Routine screening for glucose metabolism
disorders and follow up after ACS must be implemented, as
recommended.
26
It would be interesting to determine the rate
of IGT and DM in ACS patients without a history of DM in
the post-discharge phase, and assess the long-term impact of
glucose-lowering therapy on morbidity and mortality rates.
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