Emergency Department Bypass for ST-Segment Elevation Myocardial Infarction Patients Identified With a Pre-Hospital Electrocardiogram: A Report From the American Heart Association Mission: Lifeline Program

Study Questions:

What is the impact of bypassing emergency department (ED) and direct transport to the catheterization laboratory for patients identified pre-hospital with ST-segment elevation myocardial infarction (STEMI)?


The authors studied 12,581 STEMI patients identified with a prehospital electrocardiogram, treated at 371 primary percutaneous coronary intervention (PCI)-capable US hospitals participating in the ACTION Registry–Get With The Guidelines – Mission: Lifeline Program from 2008 to 2011. Reperfusion times with primary PCI and in-hospital mortality rates were compared between patients undergoing ED evaluation versus those bypassing the ED.


Patients bypassing the ED were less likely to be in shock or be in heart failure. ED-bypass rate varied significantly across hospitals (median, 3.3%; range, 0%-71%). First medical contact to device activation time was shorter (median, 68 vs. 88 minutes; p < 0.0001) with ED-bypass. The unadjusted in-hospital mortality rate was lower among ED bypass patients (2.7% vs. 4.1%, p = 0.01), with a trend toward lower mortality after adjusting for baseline differences (adjusted odds ratio [OR], 0.69; 95% confidence interval [CI], 0.45-1.03; p = 0.07). This trend was negated after excluding patients with heart failure and/or shock on presentation, and those with documented nonsystem reasons for delay (adjusted OR, 0.66; 95% CI, 0.33-1.31; p = 0.24).


The authors concluded that ED-bypass varied significantly across institutions, was relatively infrequent, and was associated with more rapid re-perfusion. No difference in adjusted mortality was observed.


Transfer of patients with STEMI directly to catheterization laboratories appears on surface to be the optimal strategy, but has potential downsides with possible negative impact on patient safety (especially the false activations) and work flow. Further research is warranted to assess the pros and cons of routinely transferring patients identified to be having a STEMI outside the hospital directly to the catheterization laboratory.

Keywords: Myocardial Infarction, Hospital Mortality, Shock, Heart Failure, Emergency Service, Hospital, Percutaneous Coronary Intervention

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