Abstract 17827: Outcome Prediction after Percutaneous Mitral Valvuloplasty: Improvements to Echocardiographic Score Based on Mechanistic Insights
Current echo scoring system for percutaneous mitral valvuloplasty (PMV) has limitations in that it does not incorporate commissural morphology which is a fundamental remodeling process in rheumatic mitral stenosis (MS). This study aimed to examine quantitative echocardiographic parameters of MV morphology reflective of derangement in rheumatic MS and their value in predicting procedural success. In addition, the new parameters were compared to current Echo score.
Methods: We examined 2D echos of 204 consecutive patients with rheumatic MS who underwent PMV from 2000 to 2011. MV morphology was assessed taking into account the pathoanatomical features of MS. Specifically, commissural area ratio (to assess the impact of commissural fusion) and the maximal leaflet displacement relative to the annulus (doming height). Procedural success, defined as an increase ≥ 50% of MV area or a final area ≥ 1.5 cm2 with a ≤ 1 grade increment of mitral regurgitation severity, were obtained in 133 patients (65%).
Results: Four independent MV morphological variables were identified, and each assigned points proportional to its regression coefficient: MV area ≤ 1cm2 (2), maximum leaflets displacement ≤ 12 mm (3), commissural area ratio ≥ 1.25 (3), and subvalvular involvement (3). An 11-point score enabled 3 risk groups to be defined with observed suboptimal results of 16.9%, 56.3%, and 73.8%. The c-statistic for predicting immediate outcome in the previous score and the new model were 0.65 and 0.80 (p<0.001), respectively. This model improved reclassification of subjects with unfavorable results of PMV, yielding a net reclassification improvement (NRI) of 45.2% (p<0.0001). The long-term outcome was predicted by age and post-procedural variables, including mitral regurgitation, mean gradient and pulmonary pressure.
Conclusion: This study demonstrates that a combination of morphological echo variables, which expresses the key pathoanatomic features of MS, accurately predicts immediate outcome after PMV. In addition, the proposed modified echocardiographic score improves outcome prediction beyond the previous score resulting in high reclassification rate, especially in the intermediate risk-group.
- © 2012 by American Heart Association, Inc.