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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 28, No 3, May/June 2017
AFRICA
187
Symptom-to-door time was defined as the interval between
the appearance of symptoms and arrival at the hospital. Door-
to-balloon time was defined as the interval between the arrival at
hospital and the time of balloon inflation. Symptom-to-balloon
time was defined as the interval between the onset of symptoms
and the time of balloon inflation.
10
Complete standard 12-lead electrocardiography was carried
out on each patient. Echocardiographic studies were performed
on all patients using the GE VIVID E9 machine with 2.5-MHz
transducers. The studies were performed by two operators
unaware of each other’s measures and of the patients’ clinical
and angiographic data. Views were taken while the patients were
in the left lateral position.
Left ventricular end-diastolic volume (LVEDV) and
end-systolic volume (LVESV) were measured from the
apical two-chamber and apical four-chamber views. Ejection
fraction (EF) was calculated using the Simpson’s method.
11
Echocardiography was done within 24 hours of admission, and
was repeated after six months. LV remodelling was defined as
≥
20% increase in the six-month LVEDV.
5
Primary PCI was performed on all patients within 12 hours
of onset of symptoms by two expert interventionists; at least
one met the criteria of individual operator level volume of the
2007 Clinical Competence Statement on Cardiac Interventional
Procedures and its 2013 revision.
12
Stenting, balloon dilatation
and/or thrombus aspiration were done, and glycoprotein (GP)
IIb/IIIa inhibitor (eptifibatide) was given as appropriate,
according to operator opinion.
TIMI flow and myocardial blush grade (MBG) were assessed
by two expert angiographers unaware of each other’s results
and of the patients’ other data. MBG was assessed according
to the dye density score as follows: MBG 0
=
no myocardial
blush or contrast density, MBG 1
=
minimal myocardial
blush or contrast density, MBG 2
=
moderate myocardial
blush or contrast density but less than that obtained during
angiography of a contralateral or ipsilateral non-infarct-
related coronary artery, MBG 3
=
normal myocardial blush
or contrast density, comparable with that obtained during
angiography of a contralateral or ipsilateral non-infarct-
related coronary artery.
13
After discharge, all patients continued to receive medical
treatment, including aspirin, clopidogrel, beta-blockers, statins,
aldosterone antagonists and angiotensin converting enzyme
inhibitors (ACEIs) or angiotensin receptors blockers (ARBs).
8
Statistical analysis
All data were analysed using the SPSS for windows package
(Version 20.0; Armonk, NY, USA: IBM Corp). Differences
between the study groups were analysed using the
χ
2
and student’s
t
-tests. Correlations between different variables were investigated
by Pearson correlation analysis. The logistic regression analysis
was evaluated by the Hosmer–Lemes goodness-of-fit test. A
p
-value
<
0.05 was regarded as being statistically significant.
In order to assess the intra-observer variability, we repeated
the measures offline for echocardiography and angiography in
30 patients within seven days of the first measure. The inter-
and intra-observer variability were calculated by dividing the
difference between the two sets of measurements by the mean of
the two observations.
Results
Twenty-eight more patients were excluded from the initial
study group (three patients died, five had a non-fatal MI and
were excluded to avoid the effect of a second infarction on LV
remodelling, five patients underwent revascularisation before
the second echocardiogram, and 15 patients were not adherent
with follow up). The remaining 232 patients (121 males and 111
females) constituted the study group.
LV remodelling was detected in 68 patients (29.3%). Patients
were divided into two groups according to the presence or
absence of LV remodelling.
Regarding clinical and echocardiographic data, and as shown
in Table 1, there was no significant difference between the two
groups regarding age, gender, diabetes, hypertension, smoking,
dyslipidaemia, door-to-balloon time, incidence of anterior
infarction, peak CK-MB level, troponin T level, basal LVEDV
or basal LVESV.
Mean EF was significantly lower in patents with remodelling
(
p
=
0.044). After six months, mean LVEDV, LVESV and
percentage of LVEDV increase were significantly higher, and
mean EF was significantly lower in patients with remodelling
(
p
<
0.00001 for each). Mean symptom-to-door and symptom-
to-balloon times were significantly higher in patients with
remodelling (
p
<
0.00001 for each).
Regarding primary PCI data, and as shown in Table 2, there
was no significant difference between the two groups regarding
stenting, thrombus aspiration, use of GP IIb/IIIa inhibitors,
infarct-related artery, incidence of patients with multi-vessel
disease, mean baseline stenosis, stent diameter, stent length, or
final residual stenosis. There was a significant difference between
the two groups regarding MBG, with more patients with MBG
0 and 1, and fewer patients with MBG 2 and 3 among patients
with remodelling (
p
<
0.00001). Mean MBG was significantly
lower in patients with remodelling (
p
<
0.00001).
Table 1. Clinical and echocardiographic data
Parameters
Remodelling
(
n
=
68)
No remodelling
(
n
=
164)
p
-value
Age (years)
58.4
±
9.73 56.5
±
10.85 0.193
Gender,
n
(%)
Male
37 (54.4)
84 (51.2)
0.659
Female
31 (45.6)
80 (48.8)
Diabetes,
n
(%)
22 (32.3)
49 (29.9)
0.71
Hypertension,
n
(%)
28 (41.2)
60 (36.6)
0.512
Smoking,
n
(%)
20 (29.4)
53 (31.5)
0.664
Dyslipidaemia,
n
(%)
23 (33.8)
55 (33.5)
0.966
Symptom-to-door time (min)
380.2
±
105.1 289.5
±
85.6
<
0.00001
Door-to-balloon time (min)
44.5
±
10.6
46.8
±
11.2
0.14
Symptom-to-balloon time (min)
424.1
±
107.3 335.8
±
93.1
<
0.00001
Anterior infarction,
n
(%)
45 (66.2)
100 (61)
0.267
Peak CK-MB (IU/l)
289.5
±
102.3 271.3
±
98.4
0.214
Troponin T (ng/ml)
10.78
±
3.95
9.85
±
4.22
0.111
Day 1 LVEDV (ml)
101.3
±
22.5
95.6
±
18.8
0.067
Day 1 LVESV (ml)
42
±
13.6
38.2
±
14.5
0.059
Day 1 EF (%)
58.4
±
5.63
60.1
±
6.22
0.044
6-month LVEDV (ml)
135.6
±
26.4 103.5
±
20.1
<
0.00001
6-month LVESV (ml)
65.6
±
18.5
40.1
±
16.3
<
0.00001
6-month EF (%)
51.6
±
9.63
61.2
±
7.14
<
0.00001
LVEDV increase (%)
33.9
±
7.53
8.26
±
6.53
<
0.00001
Data are expressed as mean
±
SD or number (%). LVEDV
=
left ventricular
end-diastolic volume, LVESV
=
left ventricular end-systolic volume, EF
=
ejec-
tion fraction.