Microvascular obstruction is the severe complication of percutaneous coronary intervention (PCI) in patients with acute coronary syndrome. Microvascular obstruction after PCI is often association with poor prognosis. Current treatments do not show improvement in prognosis of microvascular obstruction. Suxiao Jiuxin Pills (SXJX) was shown associated with a reduction in MACE, and an improvement of heart function and quality of life in acute coronary syndrome (ACS) patients with early PCI. To evaluate the effectiveness and safety of SXJX in microvascular obstruction after PCI, the investigators designed this study.

Inclusion Criteria:

• Meet the diagnosis of AMI, prepare for PCI reperfusion therapy;
• Between the ages of 18-75;
• Volunteer to participate in this study and have signed an informed consent form;
• Have a correct understanding of the significance of drug research, and have a good compliance with the observation and evaluation.

Exclusion Criteria:

• Not suitable for coronary intervention;
• With unstable hemodynamics;
• Platelet count<100×109;
• Suspected aortic dissection or acute pulmonary embolism;
• With mechanical complications;
• With uncontrolled acute left heart failure and pulmonary edema;
• With known bleeding history, active bleeding, bleeding constitution, or severe hemostatic and coagulation dysfunction;
• Meantain anticoagulants (such as warfarin or new anticoagulants);
• Severe liver and kidney insufficiency (Child-Pugh B and above, Cr>177μmol/L (2mg/dl) or eGFR<45ml/min/1.73m2);
• CTO, stent stenosis, or severe left main disease;
• History of coronary artery bypass graft surgery;
• Other pathophysiological conditions whose expected survival period is less than 1 year;
• Allergic history to Suxiao Jiuxin Pills;
• Pregnant or lactating women;
• Participating in other clinical studies;
• With other diseases that are not suitable for participating in clinical research.