Significance of commissural calcification on outcome of mitral balloon valvotomy

Abstract

Objective - To evaluate the significance of commissural calcification, identified by transthoracic echocardiography, on the haemodynamic and symptomatic outcome of mitral balloon valvotomy. Methods - Commissural calcification was graded from 0-4 using parasternal short axis transthoracic views. The morphology of the mitral valve was also assessed using the Massachusetts General Hospital echo score. Setting - A tertiary cardiac centre in Scotland. Patients - 300 patients were studied, 85 retrospectively and 215 prospectively. Mean (SD) age was 59.8 (12.7) years, range 13 to 87; 30% had been judged unsuitable for surgery. Median echo score was 6.8 (3.0), range 2-16. Main outcome measures - Immediate increase in mitral valve area and in New York Heart Association functional class 1-3 months after balloon valvotomy. Results - On univariate and multivariate analysis, commissural calcification grade was a significant predictor of achieving a mitral valve area of > 1.50 cm2 without severe mitral reflux. Its influence was greatest in patients with an echo score ≤ 8: those with commissural calcification grade 0/1 had significantly greater improvement in valve area and symptom status than those with grade 2/3; the proportions of patients achieving a final valve area of > 1.50 cm2 were 67% and 46%, respectively (p < 0.05). In patients with an echo score of > 8, the influence of commissural calcification was smaller and not significant. Conclusions - Commissural calcification as assessed by transthoracic echocardiography is a useful predictor of outcome in patients with otherwise 'good' valves (echo score ≤ 8). Calcification of one commissure or more predicts a less than 50% probability of achieving a valve area above 1.50 cm2 and is an indication for valve replacement in those who are suitable for surgery.