EMBARGO : 31 August 2015 at 14:15 BST
The ATLANTIC2 study showed that the potent P2Y12 antagonist ticagrelor given in the ambulance (pre-hospital) 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 cath lab (in-hospital)3. The rate of post-procedural definite stent thrombosis at 30 days was significantly lower in the pre-hospital group without excess bleeding.
“We hypothesised that pre-hospital 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,” said principal investigator Professor Gilles Montalescot, head of the Cardiology Department at Pitié-Salpétrière Hospital in Paris, France. “We therefore investigated the impact of pre-hospital ticagrelor in the first 24 hours after PCI in the ATLANTIC-H24 study.”
ATLANTIC was a randomised, multinational, double-blind, placebo-controlled trial in which 1 862 patients with STEMI were randomised to receive a pre- or in-hospital ticagrelor 180 mg loading dose.
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 ischaemic endpoint of death, myocardial infarction (MI), stent thrombosis, stroke or urgent revascularisation was reduced with pre-hospital ticagrelor (10.4 vs. 13.7%, p = 0.0389), as were individual endpoints of definite stent thrombosis (p = 0.0078) and MI (p = 0.0311). All endpoints except death (1.1% vs. 0.2%, p = 0.0477) favoured pre-hospital ticagrelor. There were no differences in bleeding events.
“This is an important finding because ticagrelor is needed in primary PCI but an earlier time of administration (before hospitalisation) may have an impact on the prevention of ischaemic events occurring during the first 24 hours following the procedure,” said Professor Montalescot.
The researchers found that following PCI, the largest between-group differences in platelet reactivity also occurred after PCI, when the clinical effect was observed. “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,” said Professor Montalescot.
Coronary reperfusion rates were numerically in favour of pre-hospital ticagrelor, in particular the degree of ST-segment elevation resolution was significantly greater in the pre-hospital group (median 75.0 vs. 71.4%, p = 0.049). Professor Montalescot said: “The results show that pre-hospital ticagrelor appears to improve coronary reperfusion and confirm our hypothesis that the benefits of administering ticagrelor in the ambulance manifest after PCI.”
He concluded: “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 ischaemic 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.”