Abstract Body (Do not enter title and authors here): Background:
Sex disparities in symptom presentation are well-documented in female patients with Acute Coronary Syndrome (ACS). Moreover, nearly half of the patients with acutely occlusive myocardial infarction (OMI) do not meet the STEMI criteria at admission, leading to delays in receiving emergent reperfusion. This delay may be more pronounced in female OMI patients without ST-elevation (NSTEMI-OMI), potentially due to differences in symptom presentation and recognition.

Purpose:
To investigate disparities in delays from admission ECG to percutaneous coronary intervention (PCI) between male and female patients with acute OMI stratified according to the presence of STEMI criteria.

Methods:
Electrocardiograms (ECGs), laboratory and coronary angiography (CAG) data were sourced from a total of 623 consecutive OMI patients from five international cohorts from 2012 to 2023. The final diagnosis of OMI was adjudicated by two expert physicians based on all available data. Patients were stratified into STEMI-OMI and NSTEMI-OMI based on their initial admission ECG and time-to-PCI: <2hrs vs. >2hrs, respectively. Each cohort was further subdivided based on sex (male vs. female).

Results:
A total of 314 STEMI-OMI patients (24% female) and 309 NSTEMI-OMI (30% female) were included in the analysis. Median ECG-to-balloon (E2B) time between STEMI-OMI and NSTEMI-OMI patients was 48 minutes and 17.1 hours, respectively (p<0.001). Female STEMI-OMI patients had an E2B of 47.0 minutes (95% CI: 30-78), compared to 50.6 minutes (95% CI: 30-72) for male patients, respectively, and did not differ significantly (p=0.85) (Fig 1A). In NSTEMI-OMI, female patients had a significantly longer median E2B time of 20.1 hours (95% CI: 10.2-48.2) as compared to 15.7 hours (95% CI: 5.6-28.0) (p=0.002) in male patients (Fig 1B).

Conclusion:
The present international multi-centric validation of consecutive patients with acute coronary occlusion reveals a significant sex disparity in NSTEMI-OMI patients, with female patients experiencing a 4.4-hour delay to reperfusion compared to males. These findings highlight the need for unbiased diagnostic strategies to address sex differences in ACS presentation.