Multi-center Application of Bivalirudin in Left Atrial Appendage Occlusion

Inclusion Criteria: 1. Age older than 60 years; 2. non-valvular atrial fibrillation patients with contraindication for long-term oral anticoagulant or occurrence or stroke in spite of regular administration of medication; 3. CHA2DS2 score≥2 and/or HAS-BLED score≥3; 4. Provide written informed consent. Exclusion Criteria: 1. Left atrial diameter≥65mm;Severe mitral regurgitation；percardial effusion\>3mm；LVEF\<35%; 2. Peri-procedual thrombus in left atrial and/or left atrial appendage confirmed by TEE; 3. Other comorbidities requiring for use of anticoagulants. 4. Life expectancy ≥ 1 year; 5. CHA2DS2 score ≤1 and HAS-BLED score≤2; 6. Active bleeding or bleeding constitution, bleeding tendency, including GI or urinary tract hemorrhage (3 months), cerebral hemorrhage (6 months) or cerebral infarction history (3 months), etc; 7. Other disease may lead to vascular lesions and secondary bleeding factors (such as active gastric ulcer, active ulcerative colitis, intra-cerebral mass, aneurysm, etc.); 8. Severe renal insufficiency (eGFR \< 30 mL/min/ 1.73 m2); Elevated AST, ALT level higher than three times of the normal upper limit; Advanced heart failure (NYHA classification grading of cardiac function ≥ Ⅲ) Complicated with immune system diseases； 9. Abnormal hematopoietic system：platelet count \< 100 \* 109 / L or \> 700 \* 109 / L，white blood cell count \< 3 \* 109/L etc; 10. Suffering from acute infections ,infectious diseases or other serious diseases, such as malignant tumors; 11. Known intolerance, or contraindication to any antithrombotic medication Known allergy to the study drugs and instruments (UFH, bivalirudin, aspirin and clopidogrel, stainless steel, contrast agents, etc.), or those allergic constitution. Non-cardiac co-morbid conditions are present that may result in protocol non-compliance; 12. Patients who are actively participating in another drug or device investigational study, which have not completed the primary endpoint follow-up period; 13. Patient's inability to fully cooperate with the study protocol