Impact of door-to-activation time on door-to-balloon time in primary percutaneous coronary intervention for ST-segment elevation myocardial infarctions: a report from the Activate-SF registry.
BACKGROUND
Little is known about the components of door-to-balloon time among patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention. We assessed the role of time from hospital arrival to ST-segment elevation myocardial infarction diagnosis (door-to-activation time) on door-to-balloon time in contemporary practice and evaluated factors that influence door-to-activation times.


METHODS AND RESULTS
Registry data on 347 consecutive patients diagnosed with a ST-segment elevation myocardial infarction in the emergency department over 30 months at 2 urban primary percutaneous coronary intervention centers were analyzed. The primary study end point was the time from hospital arrival to catheterization laboratory activation by the emergency department physician, and we assessed factors associated with this period. Door-to-balloon time and its other components were secondary study end points. The median door-to-activation time was 19 minutes (interquartile range, 9-54). Variation in door-to-activation times explained 93% of the variation in door-to-balloon times and demonstrated the strongest correlation with door-to-balloon times (r=0.97). Achieving a door-to-activation time of ≤20 minutes resulted in an 89% chance of achieving a door-to-balloon time of ≤90 minutes compared with only 28% for patients with a door-to-activation time >20 minutes. Factors significantly associated with door-to-activation time include the following: prehospital ECG use (61% shorter, 95% confidence interval, -50 to -72%; P<0.001) and computed tomography scan use in the emergency department (245% longer, 95% confidence interval, +50 to +399%; P=0.001).


CONCLUSIONS
The interval from hospital arrival to ST-segment elevation myocardial infarction diagnosis and catheterization laboratory activation (door-to-activation time) is a strong driver of overall door-to-balloon times. Achieving a door-to-activation time ≤20 minutes was key to achieving a door-to-balloon time ≤90 minutes. Delays in door-to-activation time are not associated with delays in other aspects of the primary percutaneous coronary intervention process.