Netherlands Heart Registration-based multicentre retrospective cohort study on primary PCI for ST-elevation myocardial infarction: comparing patient relevant outcomes in on- vs. off-hour presentations.

Aims: Over recent decades, numerous measures have been implemented to improve treatment and timely intervention for ST-elevation myocardial infarction (STEMI). For deeper insights into the current state of care, this study investigates whether patient outcomes differ based on the timing of presentation (on-hours vs. off-hours) for primary percutaneous coronary intervention (PCI) for STEMI. Methods and results: Data from STEMI PCIs performed from 2017 to October 2020, as registered within the Netherlands Heart Registration (NHR), were analysed. Off-hours presentation was defined as arrival at the catheterization laboratory (cath lab) on weekends, during working days between 17.00 and 08.00, or Monday between midnight and 08.00. Short-term outcomes included 30-day all-cause mortality and acute MI within 30 days. Long-term outcomes included all-cause mortality rates up till 5 years after PCI, target vessel revascularization within 1 year, and repeat revascularization with elective or non-STEMI PCI. The study included 19 090 STEMI patients from 17 centres, with 11 719 (61.4%) PCIs performed on-hours. No significant difference in 30-day mortality was observed between on-hours and off-hours patients (5.7% vs. 5.8%). On-hours patients had a longer time from symptom onset to cath lab arrival (≤6 h: 80.2% vs. 84.4%, P < 0.001) and were less likely to present with out-of-hospital cardiac arrest (7.6% vs. 9.5%, P < 0.001). No statistically significant differences in long-term outcomes were observed after adjusting for confounders. Conclusion: Outcomes after primary PCI for STEMI are comparable between on-hours and off-hours presentations. The quality of care appears to be independent of time of arrival at the cath lab.