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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 30, No 1, January/February 2019
32
AFRICA
In our study, we considered established atheroscletic coronary
disease as either prior MI or a revascularisation procedure. It was
notable that this was significantly higher in patients with NSTE-
ACS compared to the STEMI group (28.7 vs 5.9%,
p
<
0.001).
ACS registries and other prospective surveys have looked at MI,
PCI and coronary artery bypass grafting (CABG) separately.
In the EHS-ACS-II series, a prior MI was reported in 15.7% of
patients with STEMI and nearly double that with NSTE-ACS.
Similarly, a revascularisation procedure had been performed
in only 8.9% of STEMI and 21.5% of NSTE-ACS patients.
This suggests that patients who have pre-existing coronary
artery disease are more likely to present with NSTE-ACS than
STEMI. These data need to be understood in the context of
the relatively recent availability of facilities for diagnosis and
coronary intervention in our region.
In this study, fewer than 10% of the patients presented within
one hour of symptom onset and more than 35% presented more
than 24 hours later. The median time to presentation was more
than 12 hours. By contrast, the median time to presentation in
the the EHS-ACS-II series was less than three hours, while in the
ACCESS-SA study, the median time to presentation was 3.6 and
7.4 hours for STEMI and NSTE-ACS, respectively.
Prompt treatment from symptom onset, especially in STEMI,
is a key determinant of patient outcomes in ACS.
20
There is a
significant delay in presentation to hospital in our set-up and
this is an important factor to address. STEMI systems of care
are rudimentary or non-existent in SSA and outcomes can be
expected to be poor in this group of patients where delays to
reperfusion occur.
Reasons contributing to late presentation are probably
multifactorial and must be studied systemically in SSA, given
the unique challenges faced by patients. In many cases, a lack of
appreciation for the significance of the symptoms by the patient
and/or their initial point of medical contact, or a lack of ACS
diagnostic facilities (ECG or cardiac enzymes) will result in a
significant delay between onset of symptoms and arrival at a
facility capable of managing STEMI.
Public education and awareness programmes have been
effective in tackling this in countries with developed ACS
infrastructure. Heightened sensitivity within the healthcare
fraternity targetting such facilities may facilitate early diagnosis.
Moreover, a structured referral system that intergrates treatment
strategies, such as pre-referral thrombolysis and emergency
medical technician (EMT) services, would help to reduce delays
in treatment and improve outcomes.
In the study, 48.5% of patients with STEMI received
thrombolysis, 15.8% were subjected to primary PCI, and no
acute reperfusion was performed in nearly 35% of patients,
primarily due to delayed presentation. This contrasted with
the strategies employed in the EHS-ACS-II series in which, of
the 63.9% of patients who received primary revascularisation
treatment, a greater proportion (51.8%) of patients was treated
with primary PCI. The low rate of primary PCI compared to
thrombolysis might reflect the absence of a 24-hour on-site team,
and a perceived delay in arrival of the on-call team. Given the
low volume of pimary PCI in most cathlabs in the region, it is
not yet cost effective to have an on-site team.
However, when considering the temporal trends within our
unit, the rate of primary PCI has increased nearly two-fold from
that reported by Shavadia
et al
. in the 2008–2010 series. This
reflects the increased availability of interventional expertise and
may also reflect established processes to facilitate delivery of
these services within the unit.
STEMI patients in our series had a higher mortality rate
compared to other series.
12,19
As discussed, a large proportion
of patients in our series had a significant delay from onset
of symptoms to hospital presentation, with more than half
presenting more than 12 hours after symptom onset. It is well
known that outcomes in STEMI are strongly related to the
promptness of acute reperfusion therapy, therefore delayed
presentation of patients may account for the increased in-hospital
and long-term mortality rates compared to other series.
The STEMI group had a significantly lower LVEF and
were also more likely to develop heart failure while in hospital
compared to NSTE-ACS patients. This implies that significant
myocardial damage had occurred in a significant proportion of
these patients.
In a series that reported on long-term outcomes, early
mortality rate was often higher in STEMI patients, but by
the end of one year, this was usually similar to or lower than
in NSTE-ACS patients.
21
In our series, we noted a higher
STEMI mortality rate, even at the end of one year. Also, the
Kaplan–Meier survival estimates suggest a significantly higher
STEMI mortality rate even beyond one year. Again, this may
be associated with significant myocardial damage that occurs in
patients with STEMI, predisposing them to long-term mortality.
Heart failure or cardiogenic shock was the most common
in-hospital complication occurring in 26.5% of patients, with
STEMI patients twice as likely to develop this. In the EHS-ACS-
II series, this occurred in a significantly lower proportion of
patients (12.4%). Delays in presentation and revascularisation
could explain this.
Patient-reported readmissions due to the pre-specified major
adverse events at one year occurred in 14 of the 212 (6.6%)
patients discharged alive. Recurrent MI occurred in 10 patients,
stroke in one and bleeding requiring hospitalisation in three
patients. In the ACCESS registry, 15.6% of patients were
readmitted due to a cardiac-related event in the first year. Of
these, nearly two-thirds were admitted due to recurrent ACS,
15% due to heart failure, 1.8% due to bleeding and 6.6% due to
stroke or transient ischaemic attack.
We acknowledge that our series was subject to reporting bias
and the common limitations of retrospective analysis. However,
our response rate of 86.8% would indicate that a representative
group completed follow up. The study was conducted in an
urban, private, tertiary-level referral facility and therefore the
patient population seen here is vastly different from the general
population in Kenya. The results of this study should be
interpreted with this in mind. However, the facility is one of the
few hospitals in the region that has a well-developed cardiology
programme and this study provides previously unavailable data
on the short- and long-term outcomes of ACS in the region.
Conclusions
This single-centre report from an urban referral hospital in SSA
suggests that in-hospital and long-term mortality rates following
ACS, particularly STEMI, remain high. Delayed presentation
following symptom onset apppears to be an important
contributing factor. This needs to be studied systemically and