Introduction: Ticagrelor might reduce infarct size by exerting a more potent antiplatelet effect or by promoting a potential conditioning stimulus in ST-elevation myocardial infarction (STEMI) patients. Pre-infarction angina (PIA) is an effective preconditioning stimulus that reduces ischemia-reperfusion injury. Because little is known on the interaction of PIA in STEMI-patients loaded with ticagrelor, we sought to determine if patients loaded with ticagrelor had improved clinical outcomes as compared to clopidogrel and to study if it is modulated by the presence of PIA.
Methods: From 1272 STEMI patients submitted to primary percutaneous coronary intervention and treated with clopidogrel or ticagrelor from January 2008 to December 2018, 826 were analyzed after propensity score matching. Infarct size was estimated using peak creatine kinase (CK) and troponin T (TnT), and clinical impact was evaluated through cumulative major cardiac and cerebrovascular events (MACCE) at 1-year follow-up. Matched patients and their interaction with PIA were analyzed.
Results: Patients loaded with ticagrelor had lower peak CK [1405.50 U/L (730.25-2491.00), P < .001] and TnT [3.58 ng/mL (1.73-6.59), P < .001)], regardless of PIA. The presence of PIA was associated with lower CK (P = .030), but not TnT (P = .097). There was no interaction between ticagrelor loading and PIA (P = .788 for TnT and P = .555 for CK). There was no difference in MACCE incidence between clopidogrel or ticagrelor loading (P = .129). Cumulative survival was also similar between clopidogrel or ticagrelor, regardless of PIA (P = .103).
Conclusion: Ticagrelor reduced infarct sizes independently and without a synergic effect with PIA. Despite reducing infarct size, clinical outcomes were similar across both groups.
Keywords: STEMI; cardioprotection; conditioning; pre-infarction angina; ticagrelor.