For patients requiring interhospital transfer for primary PCI, additional delays include the door-in–door-out time in the ED of the referring center and the transport time to the receiving center (see the figure). An ACC–AHA performance measure sets a door-in–door-out goal of 30 minutes for internal quality-improvement purposes, but the metric is not used for public reporting, and the best regional STEMI systems are averaging 45 minutes. Transfer time from the door of the referring center to the door of the receiving center presents another logistic challenge. In urban centers, traffic and competition among EMS or hospital services can be problematic. In rural centers, access to transport units, geographic distances, and weather can cause time delays. The guideline recommendation for first-door-to-balloon time for transfer patients has been increased from 90 minutes to 120 minutes to encourage more transfers for primary PCI.
New England Journal of Medicine--September 5, 2013