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The Echo Score Revisited: Impact of Incorporating Commissural Morphology and Leaflet Displacement to the Prediction of Outcome for Patients Undergoing Percutaneous Mitral Valvuloplasty
Study Questions:
Do quantitative methods for assessing valvular involvement better predict immediate and long-term outcomes after percutaneous balloon mitral valvuloplasty (PBMV) for rheumatic mitral stenosis?
Methods:
Two cohorts (derivation, n = 204; validation, n = 121) of patients with symptomatic mitral stenosis undergoing PBMV were studied. Mitral valve morphology was assessed using both the conventional Wilkins qualitative parameters and novel quantitative parameters, including the ratio between the commissural areas and the maximal diastolic excursion of the leaflets from the annulus.
Results:
Independent predictors of outcome were assigned a point value proportional to their regression coefficients: mitral valve area ≤1 cm2 (2), maximum leaflet displacement ≤12 mm (3), commissural area ratio ≥1.25 (3), and subvalvular involvement (3). Three risk groups were defined: low (score of 0–3), intermediate (score of 5), and high (score of 6–11), with observed suboptimal PBMV results of 16.9%, 56.3%, and 73.8%, respectively. The use of the same scoring system in the validation cohort yielded suboptimal PBMV results of 11.8%, 72.7%, and 87.5% in the low-, intermediate-, and high-risk groups, respectively. The model improved risk classification in comparison with the Wilkins score (net reclassification improvement, 45.2%; p < 0.0001). Long-term outcome was predicted by age and post-procedural variables, including mitral regurgitation, mean gradient, and pulmonary pressure.
Conclusions:
A scoring system incorporating new quantitative echocardiographic parameters more accurately predicts outcome following PBMV than did the Wilkins model. Long-term post-PBMV event-free survival was predicted by age, degree of mitral regurgitation, and post-procedural hemodynamic data.
Perspective:
The echo score by Wilkins, et al. (Br Heart J 1988;60:299-308) is the basis for semi-quantitative grading of rheumatic mitral stenosis in anticipation of possible PBMV, using characteristics of leaflet mobility, thickening and calcification, and subvalvular thickening. Defined in the first 22 patients who underwent PBMV at Massachusetts General Hospital, all patients with a score >11 (n = 4) had a suboptimal result of PBMV, and all patients (n = 7) with a score <9 had an optimal result. Based on correlation with outcome among these 11 patients, the Wilkins echo score somehow became the benchmark for predicting the success of PBMV for rheumatic MS. In addition to failure to predict outcomes for one-half of the patients studied, the Wilkins score does not account for mitral regurgitation, a practical contraindication to PBMV. The present study uses somewhat two-dimensional echo methods to address commissural-area ratio, asymmetry of commissural thickening, and apical leaflet displacement; the authors found incremental improvement over the Wilkins echo score in correlation with PBMV outcomes. Semi-quantitative assessment of multiple characteristics of mitral valve morphology seems reasonable in attempting to predict the success of PBMV; the present study adds some new features that can be assessed.
Keywords: Rheumatic Heart Disease, Sunbathing, Mitral Valve Insufficiency, Disease-Free Survival, Calcinosis, Chymases, Angioplasty, Balloon, Coronary, Massachusetts, Hemodynamics, Tryptases, Mitral Valve Stenosis, Cardiac Surgical Procedures
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