Mitral annular calcification (MAC)

Mitral annular calcification (MAC) is more likely in those with chronic kidney disease because of the deranged calcium and phosphorus metabolism. Products of calcium and phosphorus metabolism cause soft tissue calcification. MAC is also a marker of atherosclerotic burden. Mitral annular calcification is associated with higher incidence of atrial arrhythmias, stroke and cardiovascular mortality. MAC is more common in females, elderly and in those with hypertension and diabetes. Mitral annular calcification is more likely to cause mitral regurgitation than stenosis. Two reasons could contribute to this. The normal sphincter like mechanism of mitral annular contraction during systole is prevented by calcification. Dense calcification may lift the base of the posterior mitral leaflet, causing improper coaptation with the anterior leaflet. Elevation of the base of posterior leaflet also causes chordal elongation which can lead on to chordal rupture and worsening of mitral regurgitation. Mitral stenosis due to mitral annular calcification is quite rare and occurs only with very severe forms. Unlike in rheumatic mitral stenosis, in which the smallest orifice is at the tip of the leaflets, the level of stenosis in mitral stenosis due to mitral annular calcification, the limiting orifice is at the base of the leaflets.
Source: Cardiophile MD - Category: Cardiology Authors: Tags: General Cardiology Mitral stenosis due to mitral annular calcification Source Type: blogs