A Trial Comparing the Ischemic Preconditioning Effects of Ticagrelor and Clopidogrel in Humans (ETCH)

Antiplatelet therapy remains a cornerstone in the treatment of acute and chronic coronary artery disease. Aspirin was the first such therapy to prove its benefits in acute myocardial infarction. Compared to aspirin monotherapy, the combination of aspirin and clopidogrel, a thienopyridine P2Y12 inhibitor, has been demonstrated to reduce adverse event rates among patients with acute coronary syndromes (with or without ST-segment elevation) and those receiving intracoronary stents. In the Triton-TIMI 38 trial a novel thienopyridine, prasugrel, was compared to clopidogrel in patients with acute coronary syndrome undergoing percutaneous coronary intervention. Although prasugrel significantly reduced recurrent myocardial infarction, bleeding rates were increased and no improvement in cardiac or all-cause mortality was demonstrated. However, in 2009, the authors of the PLATO trial demonstrated an unexpected cardiovascular mortality benefit with ticagrelor over clopidogrel, an endpoint not previously met by any other antiplatelet agent against an active comparator. Based on the reproducible adverse events seen in the DISPERSE, DISPERSE-2, and PLATO trials, an adenosine-mediated effect of ticagrelor is proposed.

Hypothesis: The aim of this study is to test the hypothesis that ticagrelor produces pharmacologic ischemic preconditioning, an undescribed potential off-label property of ticagrelor that could represent a plausible mechanism for its effects on cardiovascular mortality.