For patients that are presenting with ST elevation myocardial infarction (STEMI), national guidelines recommend that the door-to-balloon time be less than 90 minutes. “The problem is that when patients present to the hospital with a STEMI in the middle of the night, there may be delays in care,” explains Jorge F. Saucedo, MD.

Studies have suggested that STEMI patients who present during off-hours—weeknights, weekends, and holidays—have slower reperfusion times. “A greater emphasis has been placed on providing quality care 24/7 for STEMI,” says Dr. Saucedo. It remains unclear, however, if patients who present during off-hours receive similar quality care to those who present during on-hours.

A Closer Look

In a study published in Circulation: Cardiovascular Quality and Outcomes, Dr. Saucedo, Tarun W. Dasari, MD, and colleagues compared the care provided and survival outcomes for more than 27,000 STEMI patients arriving during off-hours with nearly 16,000 such patients who arrived during regular business hours at 447 hospitals in the United States. The analysis revealed that STEMI patients arriving during weeknights, weekends, and holidays had a 13% higher mortality risk when compared with those arriving during on-hours. “Overall, the in-hospital all-cause mortality was similar at slightly more than 4% for both groups, but the risk-adjusted all-cause mortality was higher for those who presented during off-hours,” Dr. Saucedo says.


Importantly, time of day was not associated with delays in aspirin administration, electrocardiogram tests, or intravenous clot-busting medications. However, the average door-to-balloon time was 56 minutes for those receiving care during on-hours, compared with 72 minutes for off-hour STEMI patients. “About 88% of on-hour patients achieved door-to-balloon times of less than 90 minutes, compared with a rate of approximately 79% for those arriving during off-hours,” notes Dr. Saucedo.

Progress Made, More Needed

Dr. Saucedo says that the fact that treatments were similar for both groups in the study and that only door-to-balloon time lagged slightly highlights the importance of efforts being made to continually raise awareness and educate clinicians about concordance with guideline-based care. “Over the past decade, these protocols have made a significant impact in saving lives,” he says. However, there is opportunity for improvement.

According to Dr. Saucedo, it is likely that the slower door-to-balloon times observed for STEMI patients arriving during off-hours were due to staffing issues. “During off-hours, hospital catheterization labs are typically closed and cardiac staff must be called in to treat patients,” he says. “This process consumes valuable time. The key is to standardize STEMI care so that patients can achieve the same outcomes regardless of when they present to the hospital.”


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Chin CT, Chen AY, Wang TY, et al. Risk adjustment for in-hospital mortality of contemporary patients with acute myocardial infarction: the acute coronary treatment and intervention outcomes network (ACTION) registry-Get With The Guidelines (GWTG) acute myocardial infarction mortality model and risk score. Am Heart J. 2011;161:113-122.

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