Relationship Between Time of Day, Day of Week, Timeliness of Reperfusion, and In-Hospital Mortality for Patients With Acute ST-Segment Elevation Myocardial Infarction

Abstract

Reperfusion therapy with either fibrinolytic therapy or percutaneous coronary intervention (PCI) reduces mortality for eligible ST-segment elevation myocardial infarction (STEMI) patients.^1-8 The shorter the time from symptom onset to treatment, the greater the survival benefit with either therapy.^3,9-14 The choice between therapies should take into account reperfusion treatment times.¹⁵ Although prior studies^16-18 have shown that door-to-balloon times for PCI are longer on evenings, nights, and weekends than on weekday days, several important questions remain. Prior studies neither assessed whether such variation was common to all types of hospitals nor did they determine where in the PCI process the delays occurred. In addition, these studies did not evaluate the impact of delayed door-to-balloon times on adherence to guideline recommended treatment times. Finally, previous studies focused on PCI and did not evaluate whether door-to-drug times for fibrinolytic therapy also varied by patient arrival period. Understanding the reasons for variation in reperfusion treatment times by patient arrival period, and whether such variation is common to all hospitals and to both fibrinolytic therapy and PCI, can inform the design and targeting of interventions to improve timely reperfusion.