Mitral Annulus Calcification

mitral annulus calcification

Calcification of the mitral annulus is not infrequent, seen in up to 35% of elderly patients on echocardiography which is more sensitive than CXR. It typically begins around the margins of the posterior leaflet forming a “C” (as in this case) – eventually with anterior leaflet involvement the “C” closes forming an “O”.

Although it is associated with mitral regurgitation this is of usually trivial amounts. As opposed to aortic valve calcification, calcification of the mitral annulus is not significantly associated with stenosis of the valve and contrary to previous thought, nor is it associated with strokes – when other factors are controlled for.

The calcification however can impede AV nodal conduction and therefore lead to varying degrees of heart block.

Pathologically it is important to distinguish annular calcification, which is not on the leaflet, and is covered with intact endothelium, from leaflet calcification in stenotic valves secondary to rheumatic fever.

For the whole CXR and an autopsy image (of another patient) please visit Radiopaedia.org here.

References:
1. eMedicine.com
2. Boon A et al “Mitral annulus calcification is not an independent risk factor for stroke.” J Neurol. 1997 Sep;244(9):535-41
3. Atar S et al “Mitral annular calcification: a marker of severe coronary artery disease in patients under 65 years old” Heart 2003;89:161-164
4. StatDx.com

Credit: Dr Frank Gaillard