In-hospital Mortality Outcomes of ST-segment Elevation Myocardial Infarction

Abstract

BACKGROUND: ST-segment elevation myocardial infarction (STEMI) is a common malignant complication of ischaemic heart disease. Despite optimal treatment, STEMI is often associated with significant morbidity and mortality. In high-income countries (HICs), STEMI-related morbidity and mortality incidence have decreased. However, in sub-Saharan Africa (SSA), there is an increasing burden of non-communicable diseases driven by atherosclerotic cardiovascular disease. Similarly, the incidence of STEMI is increasing. However, despite the growing burden of STEMI in SSA, there is still a paucity of data reporting on the regional morbidity and mortality associated with this disease. AIM: Hence, this study aims to provide a comprehensive description of the clinical profiles, determine the in-hospital all-cause mortality rate, and identify predictors of mortality for STEMI patients treated at the Division of Cardiology in Charlotte Maxeke Johannesburg Academic Hospital (CMJAH) in South Africa. METHODS: We conducted a retrospective review of the medical records of 815 consecutive patients diagnosed with ST-elevation myocardial infarction (STEMI), with confirmatory angiography findings, between January 1, 2015, and December 31, 2019. All participants underwent diagnostic coronary angiography, with or without percutaneous coronary intervention (PCI). As our institution is a PCI-capable centre, all patients underwent angiography either during the index admission or at a later date, and this removed ambiguity regarding the diagnosis of STEMI. The study included patients who met the third and fourth universal definitions of myocardial infarction. Data on demographics, clinical presentation, electrocardiogram (ECG) changes, biochemical parameters, coronary angiographic findings, coronary interventions, STEMI-related complications, and ongoing medical management were extracted from these sources. We compared socio-demographic characteristics, comorbidities, clinical parameters, biochemistry investigation findings, treatment, and complications between the patients who survived in-hospital and those who died. To identify predictors of in-hospital all-cause mortality in patients with STEMI, we developed a multivariable logistic regression model. RESULTS: Among 677 participants with a mean age of 55.5 ± 11.3 years, 533 (78.7%) were males. The in-hospital all-cause mortality rate was 6.2%. Co-morbidities in STEMI patients included smoking (56.1%), hypertension (52.8%), dyslipidaemia (40.0%), a family history of coronary artery disease (32.7%), and diabetes mellitus (28.3%). The median duration from the onset of chest pain to arrival at the catheterisation laboratory was two days [interquartile range (IQR): 1-3] for survivors and one day (IQR: 0-2) for non-survivors (p=0.010). Pharmaco-invasive treatment was the pre-dominant management strategy, with 61.4% of patients receiving thrombolysis and 53.9% undergoing PCI. On the age and sex-adjusted multivariable logistic regression model, the use of inotropes (OR: 4.04; CI: 1.14-14.34, p=0.031) and an increase in heart rate (OR: 1.02; CI: 1.01-1.04, p=0.010) independently predicted in-hospital all-cause mortality, while thrombolytic therapy (OR: 0.27; CI: 0.10-0.75, p=0.012), and PCI to the right coronary artery (OR: 0.03; CI: 0.00-0.46, p=0.011) reduced the risk of all-cause mortality. CONCLUSION: Our study's all-cause mortality rate among STEMI patients is comparable to rates reported in other countries globally.