Osseous and chondromatous metaplasia in calcific aortic valve stenosis

Osseous and chondromatous metaplasia are common findings in native aortic valves but do not occur in prosthetic tissue aortic valves. Bicuspid valves appear to have an inherent proclivity for metaplasia, as demonstrated by their higher rates of osseous metaplasia and/or chondromatous metaplasia both overall and at earlier age compared to tricuspid and prosthetic tissue aortic valves. This predilection could be due to aberrant hemodynamic forces on bicuspid valves, as well as intrinsic genetic changes associated with bicuspid valve formation. Aortic valve interstitial cells may play a central role in this process. Calcification of prosthetic tissue valves is most likely a primarily dystrophic phenomenon.