3. The patients had cerebral stroke within 6 months before being included, or have a history of peptic ulcer or gastrointestinal bleeding, or the patients have a bleeding tendency according to the investigator. Patients who are forbidden to use anticoagulation agents or anti-platelet drugs, and unable to tolerate aspirin or clopidogrel. Patients who are not able to tolerate and comply with dual antiplatelet therapy for at least 3 months after operation