Comparative Efficacy of Ticagrelor and Clopidogrel in ST-Elevation Myocardial Infarction Patients Undergoing Primary Percutaneous Coronary Intervention: A Cardiac Magnetic Resonance Imaging-Based Pilot Study.

Background: Ticagrelor provides faster and more consistent platelet inhibition than clopidogrel; however, its effect on myocardial injury during primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI) remains uncertain. Objectives: The aim of this pilot study was to assess the feasibility and preliminary effects of ticagrelor versus clopidogrel loading on myocardial injury in STEMI patients undergoing PCI, using cardiac magnetic resonance (CMR) imaging. Methods: Thirty STEMI patients were randomized to receive aspirin with either clopidogrel (300 mg) or ticagrelor (180 mg) before PCI, followed by standard maintenance therapy. Myocardial injury was evaluated 4-10 days post-PCI using CMR parameters (infarct size, myocardial salvage index [MSI], microvascular obstruction [MVO], and infarct transmurality). Enzymatic infarct size and 5-year clinical outcomes were also analyzed. Results: No significant differences in infarct size, MSI, MVO, or other CMR parameters were detected between the two groups. Left ventricular volume and function were comparable, with no major adverse cardiovascular events, stent thrombosis, or major bleeding over the 5-year follow-up period. Conclusions: Ticagrelor and clopidogrel showed similar effects on CMR-based myocardial injury and long-term outcomes in STEMI patients undergoing PCI. These pilot findings are hypothesis-generating and support the feasibility and inform sample-size planning for future multicenter trials.