Values of osteoprotegerin in aortic valve tissue in patients with significant aortic stenosis depend on the existence of concomitant coronary artery disease

Abstract

Introduction: Calcific aortic valve stenosis (CAVS) is a serious clinical problem. The strongest predictor of CAVS progression is the amount of calcium in the aortic valve. The pathogenesis of CAVS is largely consistent with the pathogenesis of atherosclerosis; however, about 50% of patients with CAVS do not exhibit significant atherosclerosis. Cardiovascular calcification is currently considered an actively regulated process, in which the important role is attributed to the RANKL/RANK/OPG (receptor activator of nuclear factor κB ligand/RANK/osteoprotegerin) axis. We measured OPG levels in the tissue of calcified, stenotic aortic valves in relation to the presence or absence of coronary artery disease (CAD).

Materials and methods: Aortic valve samples were collected from 105 patients with calcified, mainly severe aortic stenosis, who were divided into two groups according to the presence of CAD. In Group A (n=44), there were normal coronary artery findings, while in Group B (n=61), there was angiographically demonstrated >50% stenosis of at least one coronary artery. The control Group C (n=21) consisted of patients without aortic stenosis and with normal angiographic findings on coronary arteries.

Results: The highest tissue concentrations of OPG [median (pmol/L), 25th-75th percentile] were found in Group A [6.95, 3.96-18.37], which was significantly different compared to the other two groups (P=.026 and .001, respectively). The levels of OPG in Group B [4.15, 2.47-9.16] and in Group C [2.25, 1.01-5.08] did not differ significantly (P=.078); however, the lowest concentrations of OPG were found in Group C. Neither age nor gender in our study had effect on tissue levels of OPG (P=.994 for gender; P=.848 for age).

Conclusion: Calcified and narrowed aortic valves, compared to the normal valves, were accompanied by a change in tissue concentrations of OPG, which is, in addition, dependent on the presence or absence of CAD. The highest tissue concentrations of OPG in our work were found in patients with significant aortic stenosis without concomitant CAD.

Keywords: Aortic; Coronary; OPG; Stenosis.