Ambulance-Administered Coronary Reperfusion Is Effective

A new study shows that administration of a platelet inhibitor during transport to hospital produces better results following hospital percutaneous coronary intervention (PCI).

Researchers at Pitie-Salpetriere Hospital (Paris, France), Sheffield University (United Kingdom), and other institutions conducted a randomized, double-blind study involving 1,862 patients with ongoing ST-segment elevation myocardial infarction (STEMI) of less than 6 hours' duration, comparing ambulance and in-hospital (catheterization laboratory) treatment with ticagrelor, a platelet aggregation inhibitor produced by AstraZeneca. Co-primary end points were the proportion of patients who did not have a 70% or greater resolution of STEMI before PCI, and the proportion of patients who did not have thrombolysis in the infarct-related artery at initial angiography.

The results showed that the median time from randomization to PCI angiography was 48 minutes, with the median time difference between the two treatment strategies 31 minutes. No significant disparities were found in end point difference, major adverse cardiovascular events, or major bleeding events between groups, but the rates of definite stent thrombosis were lower in the pre-hospital group than in the in-hospital group. The study was published on September 1, 2014, in the New England Journal of Medicine (NEJM).

“Ambulance administration is safe, and may even reduce the risk of post-PCI stent thrombosis. Our study shows there is no downside to the earlier administration of ticagrelor, and it reduces the risk of post-procedure stent thrombosis, which is a serious iatrogenic complication,” said lead author Gilles Montalescot, MD, PhD, of Pitie-Salpetriere Hospital. “The ambulance is also a more practical location for drug administration than the cath lab.”

Ticagrelor blocks adenosine diphosphate (ADP) receptors of subtype P2Y12. In contrast to the other antiplatelet drugs, ticagrelor has a binding site different from ADP, making it an allosteric antagonist, and thus the blockage is reversible. Moreover, the drug does not need hepatic activation. Studies have shown that ticagrelor has lower mortality rates than clopidogrel in treating patients with acute coronary syndrome (ACS), who were less likely to die from vascular causes, heart attack, or stroke, but had greater chances bleeding.

Related Links:
Pitie-Salpetriere Hospital
Sheffield University