Continuity equation is the echocardiographic method of choice to assess degenerative mitral stenosis.

We present a rare case of a patient with severe, symptomatic degenerative calcific mitral stenosis (MS). Calcification of mitral valve annulus (MVA) is a frequent finding in elderly patients. It can be isolated or associated more often with mitral valve insufficiency than MS. In rare cases, it results in severe MS. An accurate measurement of MVA in degenerative calcific MS is problematic because the limiting orifice is near the annulus and not at the leaflet tips as in rheumatic MS. Continuity equation is the best echocardiographic method to assess the MVA in degenerative MS, correlating well with invasive methods. Real-time three-dimensional echocardiography is a promising tool and provides an accurate measurement of MVA in calcific MS, with a very good correlation compared to continuity equation. On the other hand, the use of pressure half-time is often inaccurate and should be avoided, while two-dimensional planimetry is difficult and not reliable in degenerative MS. The values of mean gradient and systolic pulmonary artery pressure depend on several factors and should be only supportive signs and should not be considered as surrogate markers of the severity of MS.