Ticagrelor Versus Clopidogrel in Myocardial Salvage in Patients With ST-elevation Myocardial Infarction (STEMI) Undergoing Primary Percutaneous Coronary Intervention: A Magnetic Resonance Imaging Study (TIGER Study)

All STEMI patients will be loaded with dual oral antiplatelet therapy of 300 mg aspirin combined with either 300 mg clopidogrel or 180 mg ticagrelor before PCI, followed by maintenance dose of 100 mg aspirin plus 75 mg clopidogrel QD or 90 mg ticagrelor BID. The duty interventional cardiologists will be responsible for patient randomization based on a pre-defined randomization chart. As it is a usual practice in Taiwan for door-to-balloon time to be within 90 minutes, we hence do not expect any impact on study results due to D2B time variation.

All STEMI patients will receive loading dose of dual oral antiplatelet therapy with 300 mg aspirin combined with either 300 mg clopidogrel or 180 mg ticagrelor before PCI, followed by maintenance dose of 100 mg aspirin plus 75 mg clopidogrel QD or 90 mg ticagrelor BID.

The primary variable is to compare myocardial salvage index (in %) as assessed by CE-MRI between 300-mg clopidogrel group and ticargrelor group. Enzymatic infarct size will also be assessed, and two methods will be used to decide that. The first is cardiac troponinI 72 hours after pain onset , while the other is peak CK level after pain onset. Sampling timing of CK will be judged by the caring physicians.

The secondary objectives include: myocardial infarct size (% of LV mass), the extent of MVO, the number of segments with >75% of infarct transmurality.