Abstract 168: The Impact of Prehospital Care on STEMI Time to Treat

In emergency cardiovascular care, delays often equate to poor patient outcomes. In patients experiencing ST-elevation myocardial infarction (STEMI), reducing systemic delays and receiving definitive treatment is a key goal of regionalized systems of care. Prehospital emergency care has been suggested to have an impact on improving STEMI patient outcomes, but little prior evidence exists in large suburban settings to establish relationships between EMS and hospital outcomes. In this study, we analyzed the entire population of non-transfer STEMI patients that underwent primary percutaneous coronary intervention (PCI) in Dallas County Texas from October 1, 2010 through December 31, 2011. Emergency medical services data from 24 agencies and 15 receiving hospitals collected and shared common, de-identified patient data. To control for confounding factors, we developed a robust generalized linear regression and relied on estimated marginal means analyses to assess the impact of EMS transport (versus self-transport) on hospital door to balloon (D2B) and total treatment time, defined as symptom onset to arterial reperfusion, or SOAR. In our analyses, there were statistically 11.1 minute reductions in median D2B (and 64.5 minute median reductions in SOAR (both with p<.001) treatment times when EMS transported to the receiving facility compared to self-transport or walk-in. More importantly, when EMS field activated the cardiac catheterization laboratory based on agreed upon processes and protocols, D2B times were reduced by 38% (or 43 minutes) after controlling for confounding variables, and field activation was associated with a 21.9% reduction (73 minutes) in the mean SOAR time (both with p<.001). We found no significant relation with mortality or length of stay. Based on these findings, we recommend regional quality improvement teams develop strategies for engaging EMS in STEMI treatment, to reduce both systemic delays and total coronary reperfusion times.