ECHOCARDIOGRAPHIC ASSESSMENT OF COMMISSURAL CALCIUM - A SIMPLE PREDICTOR OF OUTCOME AFTER PERCUTANEOUS MITRAL BALLOON VALVOTOMY

Objectives. This study was undertaken to determine whether the presenc e of calcium in the mitral valve commissures, as demonstrated echocard iographically, could predict outcome and to compare this with an estab lished echocardiographic scoring system. Background. Percutaneous mitr al balloon valvotomy is an effective form of treatment for mitral valv e stenosis. It is important to identify patients who would benefit fro m this procedure. Commissural splitting is the dominant mechanism by w hich mitral valve stenosis is relieved by this technique, and thus com missural morphology may predict outcome. Methods. One hundred forty-ni ne consecutive patients who underwent percutaneous mitral balloon valv otomy at the Mayo Clinic were evaluated retrospectively. The morpholog y of the mitral valve apparatus on the baseline echocardiograms was sc ored in blinded manner using a semiquantitative grading system of leaf let thickening, mobility, calcification and subvalvular thickening (Ab ascal score). Additionally, each of the medial and lateral commissures was graded for the presence or absence of calcification. End points w ere death, New York Heart Association functional class, repeat percuta neous mitral balloon valvotomy and mitral valve replacement at follow- up. Results. The mean follow-up period was 1.8 years (maximum 7.9 year s). Univariate predictors of death and all events combined included ag e, the use of a double-balloon technique, the presence of calcium in a commissure and the Abascal score, as continuous variables. Patients w ith an Abascal score less than or equal to 8 showed a trend toward imp roved survival at 36 months free of death, repeat percutaneous mitral balloon valvotomy or mitral valve replacement (78 +/- 6% vs. 67 +/- 8% , p = 0.07) and free of all events combined (75 +/- 6% vs. 64 +/- 8%, p = 0.07) versus those patients with a score >8. However, survival at 36 months free of death, repeat percutaneous mitral balloon valvotomy or mitral valve replacement (86 +/- 4% vs. 40 +/- 4%) and free of all events combined (82 +/- 5% vs. 38 +/- 10%) at follow-up was significan tly different between patients without commissural calcium and those w ith commissural calcium (p < 0.001). In a Cox regression model with Ab ascal score and commissural calcium and their interaction, calcificati on emerged as the only significant variable (p < 0.01). Conclusions. T he presence of commissural calcium is a strong predictor of outcome af ter percutaneous mitral balloon valvotomy. Patients with evidence of c alcium in a commissure have a lower survival rate and a higher inciden ce of mitral valve replacement and-all end points-combined. Thus, the simple presence or absence of commissural calcification assessed by tw o-dimensional echocardiography can be used to predict outcome. (C) 199 7 by the American College of Cardiology