Coronary artery calcification and serum markers

Kim, Soon Bae

Abstract

Coronary artery calcification is associated with the increased cardiovascular mortality and the extent of atheromatous plaque, especially in the hemodialysis patients. Vascular calcification was in the past considered a passive process, a degenerative consequence of aging or the result of disrupted mineral balance in the patients with chronic renal failure. It is now understood that calcium deposition in the vasculature is an active and regulated process similar to bone formation. In this issue of JKMS, Kim et al. investigate the clinical association between osteoprotegerin, an osteoclast inhibitory factor which was reported to be associated with coronary artery calcification, and fetuin-A, a systemic ectopic calcification inhibitory factor, with coronary artery calcification (CAC) score obtained from multi-slice CT. They showed that the high serum osteoprotegerin level is associated with increased CAC score and serum fetuin-A level is significantly lowered in the severe CAC score group. These results show that serum osteoprotegerin or fetuin-A level might be used as serum markers for the determination of the severity of coronary artery calcification. However, the role of serum osteoprotegerin in the formation of vascular calcification is uncertain and the pathophysiologic mechanism is not uncovered yet. Some studies suggested that the osteoprotegerin level is associated with vascular stiffness. Lower fetuin-A level is known to be a prognostic factor of cardiovascular disease mortality from several epidemiologic studies and a confirmed anti-calcifying agents in vitro experiments. In interpreting this issue of Kim et al., it is important that increased serum osteoprotegerin level might be associated with not vascular calcification but other vascular malfunction such as arterial stiffness. In conclusion, more sophisticated study needed for the clarification of the role of calcification-associated serum markers in the process of vascular calcification.