Administering an antiplatelet agent to patients with STEMI in an ambulance was safe but was no more effective at improving coronary reperfusion than treatment in the hospital, based on results from the ATLANTIC trial. Early administration may prevent stent thrombosis, though.

ATLANTIC (Administration of Ticagrelor in the Cath Lab or in the Ambulance for New ST Elevation Myocardial Infarction to Open the Coronary Artery) is a randomized, double-blind study that evaluated the safety and effectiveness of early vs. standard administration of the direct-acting platelet P2Y₁₂ receptor antagonist ticagrelor (Brilinta, AstraZeneca) before PCI in STEMI patients. The agent inhibits platelet function in less than 60 minutes, which researchers suggested might lend itself to administration during transfer to a hospital and the catheterization laboratory.

Gilles Montalescot, MD, PhD, of Pitié–Salpêtrière Hospital in Paris, and the ATLANTIC researchers published their results online Sept. 1 in the New England Journal of Medicine. The findings were presented simultaneously at the European Society of Cardiology’s meeting in Barcelona.  

Ambulance workers identified patients between 2011 and 2013 who had a diagnosis of STEMI for inclusion in the study. Patients were randomized to receive ether a 180 mg loading dose of ticagrelor in the ambulance followed by placebo in the cath lab or a placebo in the ambulance and then the 180 mg loading dose of ticagrelor in the cath lab. Both groups received 90 mg twice daily doses of ticagrelor for at least 30 days.  

The study included two primary efficacy endpoints: the proportion of patients who did not have 70 percent or greater resolution of ST-segment elevation before PCI and the proportion of patients who did not meet the criteria for Thrombolysis in Myocardial Infarction flow grade 3 in the infarct-related artery at angiography before PCI. The safety endpoint focused on bleeding (major, life-threatening and minor) within the first 48 hours and 30 days after treatment.

There was no significant difference between the 909 patients in the pretreatment group and the 953 patients in the in-hospital group for either primary endpoint. Bleeding rates were low and similar at 48 hours at 30 days in both groups.

The rate of definite stent thrombosis was lower at 48 hours and at 30 days in the pretreatment group vs. the in-hospital group (0 vs. 0.8 percent and 0.2 percent vs. 1.2 percent, respectively). “Although prespecified, stent thrombosis was a secondary end point among neutral study results; therefore, this finding should not be interpreted as definitive,” the authors cautioned.

They added that the time to PCI in the study was swift, which “may have blunted the drug effect and may not reflect routine practice.”

The ATLANTIC trial was funded by AstraZeneca.