Both Coronary Artery Calcification (CAC)and its annual progression are a strong predictors of cardiovascular events. The development of arterial calcification results from imbalance between calcification promoting and inhibiting factors. An important inhibitor of calcification is Matrix Gla Protein (MGP): a protein present in the vascular wall where it is synthesized by Vascular Smooth Muscle Cells (VSMC). MGP requires Vitamin K-mediated carboxylation to function properly. Deficiency of Vitamin K has been demonstrated to cause arterial calcification and a diet containing large amounts of Vitamin K2 was associated with lower CAC and cardiovascular risk. In animal studies, active supplementation of Vitamin K2 caused regression of existing arterial calcification. Therefore, the aim of this randomized, double-blind, placebo-controlled clinical trial is to investigate whether daily supplementation of Vitamin K2 (Menaquinone-7) to patients with established CAC will lead to a decreased progression-rate of CAC after 24 months of follow-up in comparison to placebo.

Inclusion Criteria:

• Age 18 years or older
• Baseline Coronary Computed Tomographic Angiography (CCTA) of sufficient quality
• Baseline Agatston calciumscore 100 - 400

Exclusion Criteria:

• Baseline-scan of insufficient quality
• Heart rate greater than 70 beats per minute during first scan.(despite adequate treatment with metoprolol)
• Chronic or paroxysmal Atrial Fibrillation
• Presence or scheduled coronary revascularization procedure
• History of myocardial infarction or stroke.
• Presence of Diabetes Mellitus.
• Known kidney disease or a Glomerular Filtration Rate (GFR)MDRD < 60 ml/min/1.73m2
• Malignant disease (exception: treated basal-cell or squamous cell carcinoma).
• Use of Vitamin K antagonists.
• A life-expectancy < 2 years
• Pregnancy or wish to become pregnant in the near future.