Should We Recommend Vitamin K2 Supplement to Prevent Coronary Artery Calcification for Patients Receiving Statins and/or Warfarin?

Abstract

Several reports suggest that in animal models, as well as in the clinical setting, long-term warfarin use increases coronary artery calcifications. The same has been reported for statins prescribed for patients at risk or with established atherosclerosis. Coronary calcifications are considered a risk marker for further cardiovascular events. However, numerous clinical trials have established that statins reduce the risk for cardiovascular events. Warfarin also has been shown to reduce the risk of cardiovascular events, including re-infarction. It has been suggested that the increase in coronary calcification can be viewed as a marker of stabilization of the coronary plaque in such patients. Warfarin inhibits the activation of Vitamin K epoxide reductase complex 1 (VKORC1), which blocks the regeneration of reduced vitamin K1 and K2. Vitamin K1 is predominantly localized to the liver, serving to carboxylate clotting factors. Vitamin K2 travels through systemic circulation, with significant and wide-ranging effects. Several studies using animal models of atherosclerosis have shown that vitamin K2 supplement can attenuate the progression of atherosclerosis, as well as coronary calcification. Clinical studies supporting this effect in patients are lacking. Yet, there is an increase in the use of over-the-counter vitamin K2 supplements, and several manuscripts recommended its use in patients receiving long-term warfarin to attenuate coronary calcification. However, it is unclear if this occurs in patients with atherosclerosis receiving warfarin or statins and if attenuating coronary calcification has beneficial or detrimental effects on cardiovascular outcomes.