This is a multicenter, open-label, randomized controlled study meant to test the superior efficacy of oral anticoagulation (OAC) therapy versus single antiplatelet therapy (SAPT) in patients after TAVR. Patients who accept successful TAVR will be randomized to receive either the OAC group (Vitamin-K antagonists) or the SAPT group (aspirin) for 6 months on a 1:1 ratio. After that, patients from both groups will be treated with single antiplatelet therapy (aspirin). All patients will be followed for 1 year to test the difference between net clinical benefits and bioprosthetic valve thrombosis diagnosed by 4D-CT.

Inclusion Criteria:

• Patients aged 18-85 years old with severe aortic stenosis;
• Successful TAVR via femoral artery approach (VARC 3 device success criteria);
• Implantation of self-expanding bioprosthetic valve;
• Be willing to give informed consent.

Exclusion Criteria:

• Patients with anticoagulant indications, such as atrial fibrillation, intracardiac thrombosis, deep vein thrombosis, pulmonary embolism, history of mechanical valve implantation;
• Patients needed double antiplatelet therapy, such as acute myocardial infarction within one year, coronary stent implantation within 6 months, peripheral artery stent implantation within 3 months;
• Patients who received concomitant TAVR and percutaneous coronary intervention;
• Patients with peptic ulcers or active bleeding or history of cerebral hemorrhage
• Patients with ischemic stroke or TIA within 6 months;
• Patients with left ventricular ejection fraction < 30% or pulmonary hypertension (>70mmHg) before discharge;
• Patients intolerant or allergic to aspirin or Vitamin-K antagonists (warfarin);
• Patients with evaluated glomerular filtration rate <15ml/min/m2 (Cockcroft formula) or on dialysis;
• Patients with poor compliance, unable to complete the study and follow-up as required;
• Patients' life expectancy less than 1 year;
• Patients who already participated in other clinical trials (within the last 30 days).