Seasonal variations in modes of presentation in ST elevation myocardial infarction

HHS-SM-Seasonal Variations STEMI Presentation

HHS (ED)

Introduction: For   patients with ST-elevation myocardial infarction (STEMI), time is myocardium.   The sooner STEMI patients receive a definitive intervention, the better their   outcomes. The first point of contact with the healthcare system for STEMI patients   is either via Emergency Medical Services (EMS), or self-transportation to an   Emergency Department (ED). Despite a reduced time to definitive intervention,   STEMI patients who use EMS have increased mortality compared to those who   self-transport. In an effort to optimize STEMI care pathways, we   characterized variations in modes of presentation of STEMI patients in our   region. 


Methods: This study used a retrospective cohort design from   a regional STEMI registry. Patients presenting to Hamilton Health Sciences   between January 1, 2016, and December 31, 2018 meeting STEMI criteria were   included in our analyses. Self-transport patients were analyzed from two   academic EDs in Hamilton, Ontario. One hospital was PCI capable and the   other, non-PCI capable. Patients transferred from other health regions were   excluded from our analyses. Dichotomous variables were compared using χ2   tests. Group means were compared using the Student   t-test. 


Results: Eight hundred and seventy-one patients were   included in the analysis, including 675 EMS users, and 196 self-transporting   to EDs. Patients self-transporting to EDs were younger (61.5 v. 64.6 y,   p < 0.002) and more often male (82.6 v. 69.2%,   p < 0.0002) compared to EMS users. There was a non-significant   trend towards an increased rate of all STEMI patients self-transporting in   the summer months compared to the winter (63 of 215 in summer v. 41 of 185 in   winter, 29.3 v. 22.2%, p = 0.10). Comparative analysis between both   hospitals yielded an increased rate of self-transportation to the PCI-capable   hospital in the summer months compared to winter (46 v. 28, 23.2 v. 16.3%,   p = 0.09), but not the other hospital (18 v. 13, 10.6 v. 8.3%,   p = 0.57). The majority of self-transporting patients came from   postal codes bordering each hospital, and the different rates of   self-transportation between hospitals were not associated with recent   specialist follow up at those sites. 


Conclusion: Seasonal trends in   modes of presentation in STEMI patients may present an opportunity to   optimize STEMI care pathways through resource utilization and patient   education. A larger dataset and possible multicenter analysis should be done   to determine if significance is obtained with larger sample size.


Authors: B. Forestell, M. Hewitt, S. Mondoux

Preliminary data gathering/ baseline