Long-term Anticoagulation With Oral Factor Xa Inhibitor Versus Vitamin K Antagonist After Mechanical Aortic Valve Replacement

Inclusion Criteria:

1. Age 19 and more

2. At least 3 months after mechanical aortic valve replacement

3. At least one of the conditions(as defined below) is met

• The New York Heart Association (NYHA) Functional Classification I or II; or

• According to the Valve Academic Research Consortium(VARC)2 criteria, confirmedproper valve function: no prosthesis-patient mismatch and mean aortic valvegradient <20 mm Hg or peak velocity <3 m/s, AND no moderate or severeprosthetic valve regurgitation

4. Voluntarily participated in the written agreement

Exclusion Criteria:

1. Old-generation mechanical valve

2. History of mechanical valve implantation in the mitral valve, pulmonary valve, ortricuspid valve

3. Valvular atrial fibrillation(atrial fibrillation with moderate or severe mitralstenosis)

4. Moderate to severe mitral stenosis or regurgitation

5. History of hemorrhagic stroke

6. Clinically overt stroke within the last 3 months

7. Renal failure(creatinine clearance <15mL/min) or on hemodialysis

8. Left ventricular dysfunction: Left ventricular ejection fraction (LVEF) ≤40%

9. Child-Pugh B and C hepatic impairment or any hepatic disease associated withcoagulopathy

10. Clinically significant active bleeding

11. Bleeding or hemorrhagic disorder

12. The increased risk of bleeding due to the following reasons

13. History of gastrointestinal ulcers or active ulcerations within the last 6months

14. History of intracranial or intracerebral hemorrhage within the last 6 months

15. Spinal cord vascular abnormalities or intracerebral vascular abnormalities

16. History of the brain, spinal cord, or ophthalmic surgery within the last 6months

17. History of the brain or spinal cord injury within the last 6 months

18. History of the brain or spinal cord injury or spinal tap, major regionalanesthesia, or spinal anesthesia within the last 6 months

19. Esophageal varices

20. Arteriovenous malformation

21. Vascular aneurysms

22. Malignant tumor with a high risk of bleeding

23. Bleeding tendencies associated with overt bleeding of

24. gastrointestinal, genitourinary, respiratory tract, or colorectal cancer

25. cerebrovascular hemorrhage

26. aneurysms- cerebral, dissecting aorta

27. pericarditis and pericardial effusions

28. bacterial endocarditis

29. Hemodynamically unstable or pulmonary embolism required thrombolysis or embolectomy

30. Combination therapy with other anticoagulants(Unfractionated heparin(UFH),enoxaparin, dalteparin, fondaparinux, etc.) However, the following cases arepermitted

• Switching anticoagulants

• Intravenous UFH to keep central/arterial lines open

16. Uncontrolled moderate or severe hypertension

17. Anemia at least one among the conditions(as defined below) is met 1) Hemoglobinlevel <10.0 g/dL or platelet count < 100 x 10x9/L within the last 6 months 2)Diagnosed and documented ongoing anemia

18. Infective endocarditis

19. Hypersensitivity to the main component or constituents of Rivaroxaban or Vitamin Kantagonist

20. Positive pregnancy test results (all pregnant women should undergo urinary humanchorionic gonadotropin (hCG) testing within 7 days before screening and/orrandomization) or during pregnancy or lactation

21. A genetic problem with galactose intolerance, Lapp lactase deficiency, orglucose-galactose malabsorption

22. The unsuitable condition of the protocol

23. Actively participating in another drug or device investigational study, which hasnot completed the primary endpoint follow-up period

24. Terminal illness with life expectancy <12 months

25. Vitamin K deficiency

26. Alcoholic or psychical disorder

27. Threatened abortion, eclampsia, or preeclampsia

28. Concomitant use with antiplatelet in patients with a history of stroke or transientischemic attack for the treatment of the acute coronary syndrome