Rivaroxaban Compared to Vitamin K Antagonist Upon Development of Cardiovascular Calcification

Inclusion Criteria: 1. Male or female patient aged \> 18 years 2. Need for long-term OAT according to current international guidelines for the treatment of atrial fibrillation (ACC/(American Heart Association \[AHA\]/ European Society of Cardiology \[ESC\]guidelines) and / or pulmonary embolism (ACCP/ESC guidelines). 3. Existent Coronary or Valvular Calcification, or both and an Agatston Score \> 50 in at least one location as assessed by MSCT at Screening 4. The anticipated minimum life expectancy is18 months Exclusion Criteria: 1. Patient has any clinical condition which does not allow initiation of long-term OAT including all contraindications such as hypersensitivity to active ingredient or other excipients, clinically relevant acute bleedings and all other risk circumstances according to Summary of Medicinal Product (SmPC) in which all warnings and preventive measures and precautions are described and have to be kept. 2. Hypersensitivity to active substances investigated or to any of the excipients 3. Patients had a previous coronary stent implantation in a way which makes coronary artery calcification scoring impossible or unreliable and no Valvular Calcification with Agatston Score \> 50 4. Chronic kidney disease (CKD) Stage V (GFR \<15 mL) 5. Liver disease with coagulopathy or other bleeding disorders including cirrhotic patients with Child Pugh B and C 6. Acute gastrointestinal diseases 7. Clinically significant active bleeding 8. Alcohol, opioids or drug abuse 9. Mental condition rendering the patient unable to understand the nature, scope and possible consequences of the study 10. Patient is unwilling or unable to give informed consent 11. Patient is unlikely to comply with protocol, e.g. uncooperative attitude, inability to return for follow-up visits, and unlikelihood of completing the study 12. Participation in a parallel interventional clinical trial 13. Patient has been committed to an institution by legal or regulatory order 14. Pregnant or lactating women 15. Female patient capable of bearing children without highly effective methods of birth control 16. Patient receives concomitant treatment with strong concurrent Cytochrome P 450 3A4 (CYP3A4)- and P- glycoprotein (P-gp)- inhibitors, i.e. azole-antimycotics (ketoconazole, itraconazole) or human immunodeficiency virus (HIV) protease inhibitors 17. Neuraxial Anaesthesia or spinal/epidural puncture 18. Known Endocarditis 19. Known Lactose intolerance