The AHA has not released any data or research on Hypothermia in regards to STEMI. Chris's first post was right on in that it currently is not indicated.
The keys are FMC (first Medical Contact) to Balloon in 90min or less.
It sounds like your system is already working on this goal, but you can find other information at the AHA web site. If you are not familiar the AHA has an entire STEMI project called Mission Lifeline. Here is their website.
We have not gone down that path due to lack of evidence.