Mitral valve (annular calcification)
An illustration of mitral annular calcification, an aging phenomenon which can cause mitral regurgitation. It can also be associated with calcifications of aortic cusps causing stenosis and extension of calcification into cardiac skeleton causing heart block.
With age the left ventricular cavity size decreases and the base of the ventricular septum bulges into the left ventricular outflow tract. The heart may be the site of extensive calcium deposits. Calcium deposition occurs on the aortic aspect of the aortic valve cusps. The changes may be of no clinical significance but if the deposits are extensive aortic valve stenosis can develop. The amount of aortic stenosis is directly related to the amount of calcium deposition. Calcium is also deposited in the region of the mitral annulus. The mitral leaflets thicken with fibrous tissue and mild to moderate regurgitation may occur. The posterior leaflet may take on an appearance of buckling and give an appearance similar to that seen in mitral valve prolapse. The deposition of calcium in this region is a frequent finding in the elderly. The calcium is actually deposited in a C-shaped circumferential arrangement between the under surface of the posterior mitral valve leaflet and the mural endocardium of the left ventricular wall. If the deposits are very large they bulge into the valve orifice and may cause stenosis. Calcification may also be found in the apical portions of the left ventricular papillary muscles. Calcification may also extend into the cardiac skeleton and is sometimes found in apposition to the AV conduction tissue in association with heart block. Calcifications in intimal plaques in the coronary arteries, though associated with atherosclerosis in the elderly, may not be as strongly indicative of significant coronary atherosclerosis as they might be in younger patients.