CARDIOVASCULAR JOURNAL OF AFRICA • Volume 33, No 3, May/June 2022 AFRICA 139 to perform percutaneous coronary intervention (PCI), but are unable to access these facilities.15,17,20 Indeed, 48 (77%) of these PCI facilities are privately owned and are not accessible to the majority of the population.17,19,20 Stassen et al. reports that only 14 state-owned PCI facilities are available to those without medical aid (79.9%).18-20 As state-owned PCI centres have limited capacity, the majority of South African patients with ACS are treated at primary- and secondary-level healthcare facilities in the public sector, where PCI is not available. Administrative delays at healthcare facilities and initial triaging errors further delay the initiation of appropriate medical care. Furthermore, the immediate medical management at non-PCI centres is primarily initiated by junior doctors without specialist or expert input.21 On all accounts, these reasons for delays in treatment were more evident and prolonged compared to that reported in the international literature.15 The majority of data on ACS in South Africa is anecdotal, highlighting the need for further research in this area.3,6 Additionally, international guidelines are primarily established for the developed world, where resource allocation is less constrained than in developing countries.6,11 The paucity of local data impedes our ability to adequately respond to the best window of opportunity for concerted action against the emerging epidemic and public health burden of IHD.3,6,11 As a result, several authors have called for further investigation into ACS in South Africa.1,3,6,11,18,22 The rationale for this study was, therefore, to describe the profile, clinical presentation and management of patients with ACS treated at primary- and secondary-level healthcare facilities in Cape Town, South Africa, in the hope of improving outcomes of these patients. Methods We conducted a retrospective folder review of all patients presenting to the emergency unit at New Somerset Hospital (secondary-level healthcare facility) with a suspected diagnosis of ACS between 1 January and 31 December 2016. Repeat presentations for suspected ACS were also reviewed. The study was formally approved by the Human Research Ethics Committee (HREC) of the University of Cape Town, South Africa (HREC ref no 312/2017) and complied with the Declaration of Helsinki. Potential patients were identified from the registers in the emergency unit at New Somerset Hospital. Patient folders were subsequently retrieved and reviewed to identify those who had a confirmed diagnosis of ACS. • ST-segment elevation myocardial infarction (STEMI): patients with acute ischaemic chest pain and persistent ST-segment elevation for > 20 minutes. ECG criteria included:12,23 – new ST-segment elevation at the J point in at least two contiguous leads ≥ 0.1 mV in all leads other than V2–V3; where men ≥ 40 years V2–V3 ≥ 0.2 mV; men < 40 years V2–V3 ≥ 0.25 mV; and women V2–V3 ≥ 0.15 mV – presumed new left bundle branch block: defined as QRS duration ≥ 120 ms with small initial deflection followed by deep S wave with nadir within 70 ms of onset of QRS complex in V1 or V2; broad, notched, or slurred R waves in leads I, aVL, V5 and V6; absent q waves in leads I, V5, and V6. • Non-ST-segment elevation myocardial infarction (NSTEMI): patients with acute ischaemic chest pain without persistent ST-segment elevation on ECG, but with myocyte necrosis present as proved by elevated cardiac biomarker (e.g. troponin T, troponin I, CK-MB). ECG criteria could include any of the following:13,23 – transient ST-segment elevation (< 20 minutes) – transient or persistent ST-segment depression – T-wave inversion – flat T waves or pseudo-normalisation of T waves – normal ECG. • Unstable angina pectoris (UAP): patients with a history consistent with chest pain typical of angina at rest or minimal exertion, but with a negative cardiac biomarker result (myocardial ischaemia in the absence of myocyte necrosis).13,23 Data collection included patients’ demographic data (age, gender), co-morbidities and chronic treatment prior to the index presentation, clinical presentation (including symptoms and time to FMC), troponin values and the ECG diagnosis made by the managing physicians at the primary-level healthcare centres and the secondary healthcare facility. Acute treatment [thrombolysis, low-molecular weight heparin (LMWH), antiplatelet therapy] at primary-level healthcare centres (as recorded in the referral letters) and the secondary healthcare facility was documented, as well as discharge medication from the secondary healthcare facility. LocalACSprotocol refers to thepharmacotherapyadministered to patients as appropriate for their diagnosis. For NSTEMI this included dual antiplatelet therapy (DAPT), including aspirin and clopidogrel in addition to LMWH (enoxaparin). In patients with STEMI this refers to thrombolysis (streptokinase or alteplase, depending on local availability) DAPT and LMWH, as appropriate. Outcomes included survival and referral for PCI at a tertiary healthcare facility (Groote Schuur Hospital). All ECGs were de-identified and independently analysed by two physicians with special interest in electrocardiography, who were blinded to the ECG diagnosis made by the managing physicians and the acute treatment that patients received. In the case of discrepant diagnoses, the physicians met, discussed and adjudicated the ECG diagnoses. Patients were classified as having STEMI, NSTEMI and UAP, based on the expert ECG interpretation and troponin values, in line with international guidelines for these diagnoses.12,13,23 Statistical analysis Data were collected on Research Electronic Data Capture (REDCap version 9.5.13), a secure electronic database hosted by the University of Cape Town,24 before being exported to Stata (version 14.2, StataCorp, College Station, TX, USA) for statistical analysis. Descriptive statistics were used to summarise data. Continuous variables are summarised as means with standard deviations (SD) for parametric data or median with interquartile range (IQR) for non-parametric data. Categorical variables are expressedas frequencies andpercentages.Categorical variables were compared with chi-squared, or Fisher’s exact test, where appropriate. Continuous variables were compared using either the Student’s t-test (parametric data) or Wilcoxon ranksum test (non-parametric data). Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated using univariable
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