Theoretical STEMI patient bases were defined taking into account 4 parameters:
• travel time (minutes), from each census-block of the region to each ED, during the night and during the most traffic congested hours;
• the median waiting time between the access and taking care of patients with white, green and yellow triage were calculated for each ED, as a proxy of the ED’s workload;
• the number of hospital admissions in 2012, as a proxy of hospital size
• % of patients treated with PCI within 90 minutes, as a proxy of hospital performance.
All parameters were used to assign a score to each ED and a weight was assigned to each parameter. A weighted average was calculated and each census-block was assigned to the ED with the highest score. Moreover, two constraints were established: time travel from census-block to ED must be lower than 20 minutes; ED must have hemodynamic equipment.