Chondromatous Metaplasia Within Native Cardiac Valves: Clinicopathologic Characterization with Particular Focus Upon Aortic Valves.

Native cardiac valves in the setting of chronic injury may become thickened and disrupted by dystrophic calcification, which impede valve structure/function, and there may be evidence of chondromatous (i.e., cartilaginous, CM) metaplasia admixed with dystrophic calcification. In order to characterize the presence of CM in native cardiac valves - with particular focus upon aortic valves - a retrospective review of the histologic features of 46 native aortic valves (identified from 1094 sequentially reviewed native valves of all types) containing CM were focused upon, as well as correlation with other histopathologic features, and clinical and echocardiographic findings. The prevalence rate of CM was low, and greatest among aortic valves, less in mitral valves, and never identified in tricuspid or pulmonic valves. CM in aortic valves was less commonly identified in patients with a history of autoimmune disease. The rate of CM increased with degree of valve thickening and/or calcification. The proportion of aortic valves with CM increased with an increasing degree of stenosis and decreasing degree of regurgitation, and aortic valves with CM were more commonly associated with a smaller aortic valve area, and greater peak and mean gradients. The rate of osseous metaplasia, arterial vessels, capillary bed formation, and chronic inflammation were greater in aortic valves with CM compared to valves without. CM within aortic valves is an infrequent albeit identifiable histopathologic alteration associated with chronic valve disease alongside changes in valve thickening and calcification.