Prognosis of patients with ST-elevation myocardial infarction presenting to the emergency department without chest pain: a retrospective nationwide cohort study

Background A significant proportion of patients with ST-elevation myocardial infarction (STEMI) present without cardiac symptoms of chest pain. Such presentations potentially affect the care they receive and ultimately affect these patients’ short and long-term outcomes. We analysed a national acute myocardial infarction (AMI) registry to characterise the demographics, processes of care and outcomes of non-chest pain (NCP) STEMI presentations. Methods Retrospective data for all STEMI cases from 2007 to 2020 were analysed from the Singapore Myocardial Infarction Registry. Cases which happened during inpatient and interfacility transfers were excluded. Univariable and multivariable logistic models were used to identify factors associated with NCP presentation. Cox proportional hazard models were constructed to investigate the prognostic influence of NCP on short-term and long-term mortality outcomes. ORs and HRs were calculated along with their 95% CI. Results Among 21 858 patients with first-onset STEMI, 12.6% presented with NCP. These patients were older, more likely to be women and Chinese and had never smoked. The prevalence of diabetes and hypertension was also higher. These patients were also less likely to present with other possible cardiac symptoms of AMI, such as dyspnoea and diaphoresis. They were less likely to receive percutaneous coronary intervention (36% vs 77%) and had longer door-to-balloon times (100 min vs 70 min). After adjusting for differences in baseline risk factors and clinical characteristics, NCP presentation was associated with a higher risk of all-cause mortality at 30 days (HR 2.93, 95% CI 2.62 to 3.28), 1 year (HR 2.80, 95% CI 2.56 to 3.06), 5 years (HR 2.47, 95% CI 2.30 to 2.66) and 10 years (HR 2.31, 95% CI 2.16 to 2.46). Conclusion After adjusting for baseline risk factors and treatments received, NCP presentation was still independently associated with worse survival outcomes. Further research is required to risk-stratify these patients and address the suboptimal treatment rates and outcomes.