Patients within a well-organized, high-volume, urban ST-segment elevation myocardial infarction (STEMI) network were found to have comparable management and 1-year outcomes when admitted in a primary percutaneous coronary intervention (PCI) center during on-hours or off-hours, according to a study published in JACC Cardiovascular Interventions.

Researchers examined a prospective registry for the characteristics and clinical outcomes of 2167 consecutive patients within a STEMI network admitted in a primary PCI center between January 2003 and September 2013. Admission on-hours was defined as Monday through Friday, 8 AM to 6 PM; admission off-hours was defined as Monday through Friday during the night shift (between 6 PM and 8 AM), and at any time on weekends and holidays. Time delays between symptom onset and a patient’s first physical medical contact, from first physical medical contact to sheath insertion (physician-related time), and from symptom onset to sheath insertion (total ischemic time) were assessed.

A total of 1048 (48.3%) and 1119 (51.7%) patients with a confirmed STEMI diagnosis were admitted during on- and off-hours, respectively. At the 1-year follow-up, no association was found between on- vs off-hours admission time and in-hospital mortality (8.1% vs 7.0%, respectively; P =.49) or all-cause mortality (11.0% vs 11.1%, respectively; P =.89). For patients without cardiac arrest or cardiogenic shock, admission during on- or off-hours did not affect 1-year mortality (4.5% vs 5.3%, respectively; P =.51). Patients with vs without cardiac arrest (41% vs 1.6%, respectively; P <.001) or cardiogenic shock (43.6% vs 4.9%, respectively; P <.001) had higher in-hospital and 1-year mortality rates.

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Study limitations include its reliance on a single-center registry.

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“Our analysis demonstrates that a well-organized urban STEMI network allows to bridge the gap between on-hours and off-hours management and provide the same quality of care whatever time of admission,” the researchers concluded. “Despite a well-organized STEMI network, reduction of the total ischemic time should still remain an important objective to improve clinical outcomes, facing both patient and physician dependent times.”

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.


Lattuca B, Kerneis M, Saib A, et al. On- versus off-hours presentation and mortality of ST-segment elevation myocardial infarction patients treated with primary percutaneous coronary intervention [published online October 30, 2019]. JACC Cardiovasc Interv. doi: 10.1016/j.jcin.2019.07.017