Mitral leaflet separation index-a simple novel index to assess the severity of mitral stenosis

Mitral leaflet separation (MLS) index is a recently recognized method to assess the severity of mitral stenosis. The aim of this study is to assess the severity of mitral stenosis (MS) using the MLS index.

One hundred and fifty consecutive patients with MS who underwent 2D echo were studied. In each patient the severity of MS was assessed using 2D mitral valve area, pressure half time and MLS index. The mitral leaflet separation was measured in diastole, as the maximal separation at the tips in long axis and apical 4 chamber views. There were 34 (22.7%) patients with mild MS, 52 (34.7%) patients with moderate MS and 64 (42.7%) patients with severe MS. One hundred and ten (73.3%) patients were in sinus rhythm and 40 (26.7%) patients were in atrial fibrillation. The MLS index correlated very well with MVA by planimetry (r = 0.87, P < 0.0001) and pressure half time (r = 0.86, P < 0.0001). Good correlation was found even in atrial fibrillation (r = 0.87 and r = 0.87, respectively). ROC curve demonstrates that MLS index of 0.80cm or less identified severe MS with 92% sensitivity and 92% specificity. MLS index of >1.11 cm identified mild MS with 97% sensitivity and 97% specificity.

The MLS index can be used as a screening method to semi quantify patients with mitral stenosis. This should be added into yet another method to assess the severity. This index will complement the other methods in our practice.