Hydroxyapatite Nanoclusters in Subendothelial Structures of Aortic Demilunes of Patients with Calcified Aortic Stenosis

We have studied X-ray diffraction (XRD) patterns of calcinates isolated from aortic demilunes of patients with calcific aortic stenosis. It is shown that the observed XRD pattern is formed by spherical formations of hexagonal hydroxyapatite with diameters distributed according to the lognormal law. A model of the structure of these formations is constructed and the possible mechanisms of their nucleation and encapsulation of hydroxyapatite particles in the restricted porous space of the basal membrane of aortic valve demilunes are discussed.