ATLANTIC-H24 Shows Ambulance-Administered Ticagrelor Reduces Ischemic Events 24 Hours After PCI

September 8, 2015—The European Society of Cardiology (ESC) announced that findings from the ATLANTIC-H24 study showed that P2Y12 antagonist ticagrelor (Brilinta, AstraZeneca) administered in the ambulance reduces ischemic events 24 hours after primary percutaneous coronary intervention (PCI). The ATLANTIC-H24 data were presented at the ESC Congress 2015, which was held August 29 to September 2 in London, United Kingdom.

Prof. Gilles Montalescot, who is principal investigator of ATLANTIC-H24, stated in the ESC announcement, “The results show that prehospital ticagrelor appears to improve coronary reperfusion and confirm our hypothesis that the benefits of administering ticagrelor in the ambulance manifest after PCI. The ATLANTIC24 study shows that the benefits of administering ticagrelor in the ambulance become apparent in the first 24 hours after PCI. We found differences in platelet reactivity and immediate post-PCI reperfusion that were associated with reductions in ischemic endpoints. This confirms that clinicians should consider giving ticagrelor to patients on their way to hospital for primary PCI to improve outcomes after the procedure.” Prof. Montalescot is head of the Cardiology Department at Pitié-Salpétrière Hospital in Paris, France.

In the previous ATLANTIC2 study, ticagrelor given prehospital in the ambulance in patients with ST-segment elevation myocardial infarction (STEMI) was safe but did not improve reperfusion of the culprit artery before the procedure (compared with ticagrelor given in the catheterization lab in-hospital). The rate of postprocedural definite stent thrombosis at 30 days was significantly lower in the prehospital group without excess bleeding. ATLANTIC was a randomized, multinational, double-blind, placebo-controlled trial in which 1,862 patients with STEMI were randomized to receive a pre- or in-hospital ticagrelor 180-mg loading dose.

Prof. Montalescot explained, “We hypothesized that prehospital ticagrelor may not have improved coronary reperfusion before PCI because of the short average transfer time of 31 minutes and that the effects might occur after PCI. We therefore investigated the impact of pre-hospital ticagrelor in the first 24 hours after PCI in the ATLANTIC-H24 study.” 

According to ESC, ATLANTIC-H24 was a landmark exploratory analysis in 1,629 patients who underwent primary PCI in the ATLANTIC trial. They were evaluated for platelet reactivity, coronary reperfusion (by Thrombolysis in Myocardial Infarction TIMI 3 flow and ≥ 70% ST-segment elevation resolution), and clinical endpoints during the first 24 hours after PCI.

At 24 hours, the composite ischemic endpoint of death, myocardial infarction (MI), stent thrombosis, stroke or urgent revascularization was reduced with prehospital ticagrelor (10.4% vs 13.7%; P = .0389), as were individual endpoints of definite stent thrombosis (P = .0078) and MI (P = .0311). All endpoints except death (1.1% vs 0.2%; P = .0477) favored prehospital ticagrelor. There were no differences in bleeding events.

Prof. Montalescot advised, “This is an important finding because ticagrelor is needed in primary PCI but an earlier time of administration (before hospitalization) may have an impact on the prevention of ischemic events occurring during the first 24 hours following the procedure.”

Additionally, the investigators found that following PCI, the largest between-group differences in platelet reactivity also occurred after PCI, when the clinical effect was observed. Prof. Montalescot noted, “This suggests that the biological effect of the drug, although more rapid than that of clopidogrel, takes a few hours and the early administration may be beneficial to protect the patient during the vulnerable first hours following coronary stenting.”

ESC reported that coronary reperfusion rates were numerically in favor of prehospital ticagrelor, in particular the degree of ST-segment elevation resolution was significantly greater in the prehospital group (median 75% vs 71.4%; P = .049).