Association between mitral annular calcification and progression of mitral and aortic stenoses

Background: Mitral annular calcification (MAC) is a chronic degenerative process affecting the annular fibrosus of the mitral valve. We sought to examine the relationship between MAC and the progression of valve disease.

Methods: The echocardiography database was searched for patients with MAC who had undergone at least two studies more than 1 year apart. The degree of MAC was quantified according to both extent and thickness. The degree of aortic stenosis (AS) and mitral stenosis (MS) was classified according to valve area and mean gradient, respectively.

Results: Of 125 patients, moderate or greater AS was present in 8 of 86 (9.3%) patients with mild, 12 of 29 (41.4%) patients with moderate, and 4 of 10 (40%) patients with severe MAC extent, P = .0002. The rate of progression of AS was highest in those with greatest MAC extent (0.21 cm² /y) or greatest MAC thickness (0.28 cm² /y) compared with those with least MAC extent (0.09 cm² /y) or thickness (0.07 cm² /y), P = .04 and <.0001, respectively. The rate of progression of mean mitral gradient was highest in those with greatest MAC extent (0.71 mm Hg/y) or greatest MAC thickness (0.17 mm Hg/y) compared with those with least MAC extent (0.07 mm Hg/y) or thickness (0.07 mm Hg/y), P = .0003 and P < .0001, respectively. Patients with greatest MAC extent had lower survival than those with lower MAC extent, P = .03. However, there was no difference in survival between patients with different MAC thickness, P = .43.

Conclusion: Both the degree of MAC extent and thickness are associated with the rate of progression of aortic and mitral stenosis and may serve as a risk marker for future progression.