Vascular CalcIfiCation and sTiffness Induced by ORal antIcoAgulation

Inclusion Criteria: * Male or female patient aged \> 18 years * Female patient capable of bearing children with highly effective methods of birth control * Creatinine clearance \> 30 ml/min * Normal hepatic function based on hepatic enzymes * Treated for atrial fibrillation according a score superior at 1 * Treatment duration 12 months according to the actual recommendations * Treated by vitamine K antagonist less than 2 months before entering the study * Patient willing to participate with a signed informed consent * Patient covered by a healthcare insurance Exclusion Criteria: * Patient has any clinical condition which does not allow initiation of long-term 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 in which all warnings and preventive measures and precautions are described and have to be kept. * Patients had a previous coronary stent implantation * Creatinine clairance \<30 mL) * Liver disease with coagulopathy or other bleeding disorders including cirrhotic patients with Child Pugh * Hyperthryroidism * Hypercalcemia * Hyperphosphatemia * Acute gastrointestinal diseases * Mental condition rendering the patient unable to understand the nature, scope and possible consequences of the study * Patient is unwilling or unable to give informed consent * Patient is unlikely to comply with protocol, e.g. uncooperati…