At present, the treatment methods for coronary heart disease include drug therapy, interventional therapy and surgical treatment (coronary artery bypass grafting) according to the condition. Among them, interventional therapy is welcomed by the majority of patients with coronary heart disease for its minimally invasive and non-invasive effect, but it has strict indications and contraindications. I. Indications for coronary intervention 1. Patients with stable angina who are still symptomatic after drug treatment and whose narrowed vessels supply a large area of surviving myocardium at risk. 2.Patients with mild angina symptoms or asymptomatic, but with clear objective evidence of myocardial ischemia, significant stenotic lesions, and lesions supplying medium to large areas of surviving myocardium. 3, Patients with angina recurrence and lumen restenosis after interventional treatment. 4. Patients with acute ST-segment elevation myocardial infarction within 12 hours of onset; or within 12 to 24 hours of onset, with severe heart failure and/or hemodynamics, electrocardiographic instability and/or evidence of severe myocardial ischemia are eligible for emergency PCI. 5. Patients with recurrent angina after bypass surgery. 6., Unstable angina is still unstable after active drug treatment, and there is evidence of myocardial ischemia during angina attack. Pre-operative considerations before PCI An iodine allergy test, platelet count, clotting time, liver and kidney function and electrolyte examination and screening for infectious diseases are required before PCI. For elective surgery, fast for 4 to 6 hours before surgery, and take aspirin and clopidogrel before surgery; for emergency surgery, if no antithrombotic drugs are used before surgery, chew 300mg of aspirin and 600mg of clopidogrel before surgery, and use heparin routinely during surgery. C. Precautions after PCI The risk factors of coronary heart disease should still be actively controlled after PCI, such as quitting smoking, controlling blood pressure, blood sugar, blood lipid and weight standard. Take aspirin for life after the operation. For implantation of bare stent, clopidogrel should be taken for 1 month to 3 months; for implantation of drug-eluting stent, clopidogrel should be taken for 9 months to 12 months. Regular follow-ups were performed in the first, third, sixth and twelfth months after surgery.