Current Status of Emergency Medical Service Use in ST-segment Elevation Myocardial Infarction in China: Findings from China Acute Myocardial Infarction (CAMI) Registry.

Background: The mortality rate of myocardial infarction in China has increased dramatically in the past three decades. Although emergency medical service (EMS) played a pivotal role for the management of patients with ST-segment elevation myocardial infarction (STEMI), the corresponding data in China are limited. Methods: An observational analysis was performed in 26,305 STEMI patients, who were documented in China acute myocardial infarction (CAMI) Registry and treated in 162 hospitals from January 1st, 2013 to January 31th, 2016. We compared the differences such as demographic factors, social factors, medical history, risk factors, socioeconomic distribution and treatment strategies between EMS transport group and self-transport group. Results: Only 4336 patients (16.5%) were transported by EMS. Patients with symptom onset outside, out-of hospital cardiac arrest and presented to province-level hospital were more likely to use EMS. Besides those factors, low systolic blood pressure, severe dyspnea or syncope, and high Killip class were also positively related to EMS activation. Notably, compared to self-transport, use of EMS was associated with a shorter prehospital delay (median, 180 vs. 245 min, P < 0.0001) but similar door-to-needle time (median, 45 min vs. 52 min, P = 0.1400) and door-to-balloon time (median, 105 min vs. 103 min, P = 0.1834). Conclusions: EMS care for STEMI is greatly underused in China. EMS transport is associated with shorter onset-to-door time and higher rate of reperfusion, but not substantial reduction in treatment delays or mortality rate. Targeted efforts are needed to promote EMS use when chest pain occurs and to set up a unique regionalized STEMI network focusing on integration of prehospital care procedures in China.