Intracoronary rhTNK-tPA Versus Tirofiban in Patients With STEMI and High Thrombus Burden

Inclusion Criteria: * Age 18-75 years old; * STEMI within 12 hours of onset; * TIMI flow grade 0-2 or TIMI thrombus grade ≥4 after thrombus aspiration or balloon dilation * Radial artery access Exclusion Criteria: * A functional coronary collateral supply (Rentrop grade≥2) to the infarctrelated artery * Known or suspected old myocardial infarction of target vessels * Rescue PCI * Cardiogenic shock * Contraindications to Tirofiban or rhTNK-tPA * Severe hepatic and renal insufficiency (alanine aminotransferase ≥5 upper limit of normal; estimated glomerular filtration rate \<30ml/min/1.73m2, or on dialysis) * Prolonged (\> 10 minutes) cardiopulmonary resuscitation * Definite mechanical complications (including ventricular septal perforation, or rupture of the Papillary tendon bundle, or rupture of the left ventricular free wall) * Severe chronic obstructive pulmonary disease or respiratory failure * Severe infection * Neurological disorders * Malignant tumors or other pathophysiological conditions with an expected survival time of less than 1 year * Pregnant or lactating women