Association Between Patient and System Delays and In-Hospital Mortality in Primary PCI for STEMI: Findings from a Large, Nationwide Inpatients Sample

System delay is associated with mortality in patients undergoing primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI). However, the influence of patient delay has been relatively overlooked. We aimed to evaluate the influence of patient and system delays on STEMI patients undergoing primary PCI in China. STEMI patients registered at the Nationwide Chinese Cardiovascular Association Database-Chest Pain Center from January 2017 to September 2021 were screened. The exposures were total ischemic time (TIT), system delay and patient delay. The primary outcome was in-hospital mortality. Among 458,260 patients from 2529 centers, median TIT, system delay and patient delay were 4.1, 1.5 and 2.1 hours, respectively. The adjusted odds ratio of in-hospital mortality increased by 2.2% (odds ratio [OR], 1.022, 95% confidence interval [CI], 1.017-1.027), 2.3% (1.023, 1.006-1.040) and 2.2% (1.022, 1.017-1.027) for every one-hour increase in TIT, system delay and patient delay, respectively. Patient delay demonstrated a comparable impact to system delay on in-hospital mortality among STEMI patients undergoing primary PCI. Widespread primary PCI-capable center, improved awareness about myocardial infarction and regional transfer system are essential to shorten patient delay. [Display omitted]