Prevention of Coronary Slow Flow or No-Reflow During EPCI in Patients With Acute STEMI

Inclusion Criteria: * Ischemic symptoms \< 2 weeks (\> 24 hours) * Continued ischemic chest pain \> 30min * ST-segment elevation ≥ 0.1 millivolt in 2 or more contiguous leads on the 12-lead ECG or new left bundle branch block (LBBB) * Detection of a rise of cardiac biomarker values with at least one value above the 99th percentile upper reference limit (URL) * Elective coronary artery angiography was planned. Exclusion Criteria: * Emergency thrombolytic therapy was performed before elective coronary artery angiography * Cardiogenic shock with no response to hypervolemic treatment or vasopressor * Severe cardiomyopathy or valvular disease requiring intervention * Coronary ectasia * Severe heart failure * Contraindication or allergy to antiplatelet drugs * Contraindication or allergy to experimental drugs * Unable to receive at least 1 year of dual antiplatelet therapy * Active bleeding or extreme-risk for major bleeding * Severe liver or renal failure * Life expectancy \< 1 year * Unable or unwilling to provide informed consent * Women of child bearing potential * Under 18 years of age * Hemoglobin \< 90g/L * Platelet count \< 100×10\^9/L * Can not cooperate (with mental disorders or cognitive disorders)