CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 6, July 2012
AFRICA
319
(I, II, III or IV) and time from symptom onset to hospital
presentation (minutes).
•
ECG and laboratory findings: predominant rhythm,
ST-segment and T-wave changes were recorded according to
the ECG site of myocardial involvement. Serum chemistries
included biomarkers of myocyte necrosis (CK-MB, troponin
I levels), fasting lipid profile including total cholesterol, high-
density lipoprotein, low-density lipoprotein, blood glucose
(mmol/l) levels and calculated creatinine clearance (ml/min)
at presentation using the Cockcroft-Gault formula.
•
Risk factor assessment: a record of pre-existing type 2 diabe-
tes mellitus, hypertension, cigarette smoking status, history
of dyslipidaemia, family history of premature coronary
artery disease, prior anginal episodes, myocardial infarction,
percutaneous coronary interventions (PCI) or coronary artery
bypass graft (CABG) operations and prior history of stroke/
cerebrovascular accident was obtained from the patients’
history and medical notes.
•
Diagnosis and management: all patients were sub-grouped
into two classes: STEMI and NSTEMI/UA, according to the
ECG and serum biomarkers of myocyte necrosis. Management
strategies were analysed in terms of reperfusion therapy and
adjunctive therapies administered during hospitalisation.
–– acute reperfusion strategy and modality utilised (none,
fibrinolysis, PCI) for the STEMI subgroup.
–– adjunctive therapy including the use of anti-thrombotic
therapy, antiplatelet agents, beta-blockade, angiotensin
receptor blockade and lipid-lowering agents.
All patients who underwent diagnostic coronary angiography
alone or in addition to PCI had their angiographic findings and
procedural details recorded.
•
Outcomes: in-hospital outcomes were recorded according
to the proportion of patients alive and complications (heart
failure, major bleeding, post-myocardial infarction (MI)
re-infarction and sudden death) at discharge.
Statistical analysis
All patients were grouped into either STEMI or NSTEMI/UA
and data were subsequently analysed using SPSS version 15.0.
All continuous variables are expressed as mean ± standard
deviation. Categorical variables are expressed as percentages.
Statistical comparisons between subgroups were performed
using the Chi-square test, the Fisher exact test for categorical
variables, and the Student’s
t
-test for continuous variables, and
regression analyses as appropriate, using SPSS.
Results
A total of 2 156 mainly medical patients were admitted to the
high dependency and intensive care units between April 2008
and May 2010, 111 (5.1%) of whom had a confirmed diagnosis
of ACS. Fifty-six per cent (62) of the patients had a diagnosis of
STEMI with the rest being NSTEMI/UA (44%). The baseline
characteristics and risk-factor profiles of these groups are shown
in Tables 1 and 2.
About 58% (36) of the STEMI patients and 72% (36) of
the NSTEMI/UA patients had one or two of the risk factors
described above, while 14% (nine) and 16% (eight) of the
STEMI and NSTEMI/UA arms, respectively, had none of the
above traditional risk factors at presentation. Over 85% (52)
of the patients in the STEMI subgroup had a TIMI risk score
between two and eight, while 69.4% (34) in the NSTEMI/UA
subgroup had a score of two and three at admission. The site
of myocardial involvement in patients with STEMI is shown in
Fig. 1.
The current ACS management strategy for STEMI at
AKUHN is prompt fibrinolysis within 30 minutes, and primary
PCI whenever deemed logistically feasible within 90 minutes of
arrival. Fifty-five per cent (34) of patients presenting with STEMI
received fibrinolysis, with the majority receiving tenecteplase.
Thirteen per cent (eight) of the patients underwent primary PCI
because they had an absolute contraindication to fibrinolysis.
Over 30% (20) of the patients did not receive any form of
reperfusion, primarily due to late presentation at hospital.
TABLE 2. CARDIOVASCULAR RISK FACTOR PROFILE
STEMI
(
n
= 62)
NSTEMI/UA
(
n
= 49)
p
History of diabetes mellitus (%)
38.7
34.7
NS
History of hypertension (%)
46.8
51.0
NS
Current smoker (%)
24.2
22.4
NS
Family history of CAD (%)
16.1
16.3
NS
Dyslipidaemia (%)
9.7
20.4
NS
Prior angina (%)
6.5
14.3
NS
History of CABG (%)
1.6
0
NS
Previous PCI (%)
3.2
2.0
NS
Previous MI (%)
6.5
12.2
NS
History of stroke (%)
0
4.1
NS
Total cholesterol (mmol/l)
5.4
±
1.4
5.5
±
1.6 NS
LDL-C (mmol/l)
3.3
±
1.0
3.0
±
1.2 NS
HDL-C (mmol/l)
1.1
±
0.5
0.9
±
0.2 0.018
CAD
=
coronary artery disease, PCI
=
percutaneous coronary interven-
tions, CABG
=
coronary artery bypass graft, MI
=
myocardial infarct,
LDL-C
=
low-density lipoprotein cholesterol, HDL-C
=
high-density
lipoprotein cholesterol.
TABLE 1. BASELINE CHARACTERISTICS OF
PATIENTS PRESENTINGWITHACS
STEMI
(
n
= 62)
NSTEMI/UA
(
n
= 49)
p
Mean age (years)
63.3
±
13.0 64.5
±
15.2 NS
Male gender (%)
80.6
69.4
NS
BMI (kg/m
2
)
26.7
±
3.9 27.3
±
4.8 NS
Chest pain as presenting symptom (%)
83.9
69.4
NS
Mean time to presentation (hours after
symptom onset)
12.9
±
17.3 29.3
±
52.8 0.02
Mean systolic BP at presentation
(mmHg)
133
±
35 139
±
29 NS
Mean heart rate at admission (bpm)
85
±
22
82
±
18 NS
Killip class (%)
I
II
III
IV
88.7
11.3
0
0
89.8
4.1
6.1
0
ECG rhythm at presentation (%)
Sinus
Atrial fibrillation
Other
91.9
3.2
4.8
93.9
4.1
2.0
Random glucose at admission (mmol/l) 8.9
±
5.0 6.9
±
3.2 0.009
Creatinine clearance (ml/min)
68.3
±
31.3 64.2
±
31.3 NS
bpm = beats per minute, NS = non-significant.
