Background::It remains unclear whether the outcomes of ST-elevation myocardial infarction (STEMI) patients treated with primary percutaneous coronary intervention (PPCI) during off-hours are as favorable as those treated during on-hours, especially those with a first medical contact-to-device (FMC-to-device) time within 90 min. We aimed to determine whether off-hours admission impacted late outcomes in patients undergoing PPCI and with an FMC-to-device time ≤90 min.Methods::This multicenter retrospective study included 670 STEMI patients who underwent successful PPCI and had an FMC-to-device time ≤90 min from 19 chest pain centers in Beijing from January 2018 to December 2018. Patients were divided into on-hours group and off-hours group based on their arrival time. Baseline characteristics, clinical data, and key time intervals during treatment were collected from the Quality Control & Improvement Center of Cardiovascular Intervention of Beijing by the “Heart and Brain Green Channel” app.Results::Overall, the median age of the patients was 58.8 years and 19.9% (133/670) were female. Of these, 296 (44.2%) patients underwent PPCI during on-hours and 374 (55.8%) patients underwent PPCI during off-hours. Compared with the on-hours group, the off-hours group had a longer FMC-to-device time and fewer patients with FMC-to-device time ≤60 min (n P 0.05). According to the Cox regression analyses, off-hours admission was not a predictor of 2-year MACEs ( n P = 0.788). Similarly, the Kaplan-Meier curves showed that the risks of a MACE, all-cause death, reinfarction, and target vessel revascularization were not significantly different between the two groups (n P > 0.05).n Conclusions::This real-world, multicenter retrospective study demonstrated that for STEMI patients who underwent PPCI within 90 min, off-hours admission was safe, with no difference in the risk of 2-year MACEs compared with those with on-hours admission.“,”Background::It remains unclear whether the outcomes of ST-elevation myocardial infarction (STEMI) patients treated with primary percutaneous coronary intervention (PPCI) during off-hours are as favorable as those treated during on-hours, especially those with a first medical contact-to-device (FMC-to-device) time within 90 min. We aimed to determine whether off-hours admission impacted late outcomes in patients undergoing PPCI and with an FMC-to-device time ≤90 min.Methods::This multicenter retrospective study included 670 STEMI patients who underwent successful PPCI and had an FMC-to-device time ≤90 min from 19 chest pain centers in Beijing from January 2018 to December 2018. Patients were divided into on-hours group and off-hours group based on their arrival time. Baseline characteristics, clinical data, and key time intervals during treatment were collected from the Quality Control & Improvement Center of Cardiovascular Intervention of Beijing by the “Heart and Brain Green Channel” app.Results::Overall, the median age of the patients was 58.8 years and 19.9% (133/670) were female. Of these, 296 (44.2%) patients underwent PPCI during on-hours and 374 (55.8%) patients underwent PPCI during off-hours. Compared with the on-hours group, the off-hours group had a longer FMC-to-device time and fewer patients with FMC-to-device time ≤60 min (n P 0.05). According to the Cox regression analyses, off-hours admission was not a predictor of 2-year MACEs ( n P = 0.788). Similarly, the Kaplan-Meier curves showed that the risks of a MACE, all-cause death, reinfarction, and target vessel revascularization were not significantly different between the two groups (n P > 0.05).n Conclusions::This real-world, multicenter retrospective study demonstrated that for STEMI patients who underwent PPCI within 90 min, off-hours admission was safe, with no difference in the risk of 2-year MACEs compared with those with on-hours admission.