Background The direct-acting platelet P2Y12 receptor antagonist ticagrelor can reduce
the incidence of major adverse cardiovascular events when administered at hospital
admission to patients with ST-segment elevation myocardial infarction (STEMI). Whether
prehospital administration of ticagrelor can improve coronary reperfusion and the
clinical outcome is unknown. Methods We conducted an international, multicenter, randomized,
double-blind study involving 1862 patients with ongoing STEMI of less than 6 hours'
duration, comparing prehospital (in the ambulance) versus in-hospital (in the catheterization
laboratory) treatment with ticagrelor. The coprimary end points were the proportion
of patients who did not have a 70% or greater resolution of ST-segment elevation before
percutaneous coronary intervention (PCI) and the proportion of patients who did not
have Thrombolysis in Myocardial Infarction flow grade 3 in the infarct-related artery
at initial angiography. Secondary end points included the rates of major adverse cardiovascular
events and definite stent thrombosis at 30 days. Results The median time from randomization
to angiography was 48 minutes, and the median time difference between the two treatment
strategies was 31 minutes. The two coprimary end points did not differ significantly
between the prehospital and in-hospital groups. The absence of ST-segment elevation
resolution of 70% or greater after PCI (a secondary end point) was reported for 42.5%
and 47.5% of the patients, respectively. The rates of major adverse cardiovascular
events did not differ significantly between the two study groups. The rates of definite
stent thrombosis were lower in the prehospital group than in the in-hospital group
(0% vs. 0.8% in the first 24 hours; 0.2% vs. 1.2% at 30 days). Rates of major bleeding
events were low and virtually identical in the two groups, regardless of the bleeding
definition used. Conclusions Prehospital administration of ticagrelor in patients
with acute STEMI appeared to be safe but did not improve pre-PCI coronary reperfusion.
(Funded by AstraZeneca; ATLANTIC ClinicalTrials.gov number, NCT01347580 .).
