The measure definition follows the guidelines in the American College of Cardiology/American Heart Association Guidelines for the Management of Patients with (ST-Elevation) Myocardial Infarction. The time-to-treatment recommendations in these Guidelines start with when the patient presents to the medical system. The Guidelines recommend 90 minutes (from medical system contact) to treatment with PCI, longer than the recommendation for time-to-treatment with fibrinolytics. The longer time frame for PCI in the updated Guidelines recognizes the logistical maneuvers hospitals must set in motion when a patient requires PCI, including summoning the treatment team, transferring the patient from the emergency department to the cardiac catheterization laboratory, and performing the procedure.
STEMI patients were excluded if they were transferred in, received rescue or facilitated PCI, or if they had a non-system reason to delay primary PCI.