STEMI During “Off-Hours” Does Not Lead to Worse Outcomes

STEMI On Hours vs Off Hours Outcomes
STEMI On Hours vs Off Hours Outcomes
Patients with STEMI who present off-hours do not have worse outcomes than those who present during the workday.

Results of a study suggest that patients who present with ST-segment elevation myocardial infarction (STEMI) outside of normal working hours do not have worse outcomes than patients who present with STEMI during the workday.

“We examined STEMI patients presenting ‘off-hours’ (nights, weekends, holidays) because prior studies had suggested they have worse outcomes,” Deepak L. Bhatt, MD, MPH, study investigator from Brigham and Women’s Hospital Heart & Vascular Center, told Cardiology Advisor.

Dr Bhatt and colleagues presented their findings at the 2016 European Society of Cardiology Congress in Rome and were simultaneously published in the Journal of the American College of Cardiology.

Patients presenting with STEMI off-hours may have worse outcomes than those presenting during the workday (on-hours) due to delayed time to percutaneous coronary intervention (PCI), staffing issues, and higher complication rates. But prior data regarding treatment of STEMI patients off-hours were largely derived from registries and were collected retrospectively.1,2

Whether off-hours PCI still leads to worse outcomes in current-day practice remains a subject of debate. Dr Bhatt and colleagues sought to evaluate differences in outcomes between off-hours and on-hours presentation of STEMI in a substudy of CHAMPION PHOENIX, a contemporary, prospective trial on cangrelor during PCI.3

A total of 1992 patients with recent STEMI from the CHAMPION PHOENIX trial were categorized into 2 groups based on time of presentation: on-hours (7 am to 7 pm) and off-hours (7 pm to 7 am, weekends, and holidays). The primary efficacy outcome was composite stent thrombosis, all-cause mortality, or ischemia-driven revascularization at 48 hours.

No significant difference in risk of the primary outcome was found between the on-hours group and off-hours group (relative risk [RR]: 1.11; 95% confidence interval [CI]: 0.68-1.83; P= .67). Rates of stent thrombosis were also similar (adjusted RR: 0.57; 95% CI: 0.27-1.21; P= .15).

The primary safety end point, GUSTO-defined (Global Use of Strategies to Open Occluded Coronary Arteries) moderate or severe bleeding, was not significantly different for on-hours PCI vs off-hours PCI (P= .22).

Patients in the on-hours group were more likely to have diabetes or history of prior PCI or to receive higher doses of medications such as bivalirudin, clopidogrel, heparin, or drug-eluting stent (P< .05 for all comparisons). Time from symptom onset to PCI was shorter in the off-hours group (median: 5.00 vs 5.98 hours in the on-hours group; P< .0001).

“In our international study of contemporary primary PCI practice, we found that outcomes off-hours were as good as on-hours,” Dr Bhatt concluded. “Potentially, this improvement in practice over time is due to quality improvement efforts in primary PCI, such as those by the American College of Cardiology and American Heart Association. Of course, the sites in this clinical trial were all experienced, high-volume hospitals, so further research is necessary to see whether our results can be generalized to other types of hospitals.”

Disclosures: Several authors disclosed financial relationships with pharmaceutical companies.


  1. Selvaraj S, Bhatt DL, Stone GW, et al; for the CHAMPION PHOENIX Investigators. “Off-hours” vs “on-hours” presentation in ST-segment elevation myocardial infarction: findings from CHAMPION PHOENIX. J Am Coll Cardiol. 2016.  doi:10.1016/j.jacc.2016.08.023.
  2. Selvaraj S, Bhatt DL, Stone GW, et al. Abstract P5648. Off hours vs on hours presentation in ST-segment elevation myocardial infarction: findings from CHAMPION PHOENIX. Presented at the European Society of Cardiology Congress. August 27-31, 2016; Rome, Italy. 
  3. Bhatt DL, Stone GW, Mahaffey KW, et al; for the CHAMPION PHOENIX Investigators. Effect of platelet inhibition with cangrelor during PCI on ischemic events. N Engl J Med. 2013;368(14):1303-1313. DOI: 10.1056/NEJMoa1300815.