Total Ischaemic Time in STEMI: Factors Influencing Systemic Delay

Total ischaemic time in ST-elevation myocardial infarction (STEMI) has been shown to be a predictor of mortality. The aim of this study was to assess the total ischaemic time of STEMIs in an Irish primary percutaneous coronary intervention (pPCI) centre. A single-centre prospective observational study was conducted of all STEMIs referred for pPCI from October 2017 until January 2019. There were 213 patients with a mean age 63.9 years (range 29-96 years). The mean ischaemic time was 387 ± 451.7 mins. The mean time before call for help (patient delay) was 207.02 ± 396.8 mins, comprising the majority of total ischaemic time. Following diagnostic electrocardiogram (ECG), 46.5% of patients had ECG-to-wire cross under 90 mins as per guidelines; 73.9% were within 120 mins and 93.4% were within 180 mins. Increasing age correlated with longer patient delay (Pearson's r=0.2181, p=0.0066). Women exhibited longer ischaemic time compared with men (508.96 vs. 363.33 mins, respectively, p=0.03515), driven by a longer time from first medical contact (FMC) to ECG (104 vs. 34 mins, p=0.0021). The majority of total ischaemic time is due to patient delay, and this increases as age increases. Women had longer ischaemic time compared with men and longer wait from FMC until diagnostic ECG. This study suggests that improved awareness for patients and healthcare staff will be paramount in reducing ischaemic time.