Comparison of long-term (over 10 years) outcome of percutaneous mitral balloon valvuloplotomy between moderate and severe mitral stenosis

Background and Objectives: Percutaneous mitral balloon valvuloplotomy (PMV) is a safe and effective procedure for the treatment of mitral stenosis (MS); however, its long-term results according to the severity of MS remain unknown. The aim of this study was to compare the long-term results of PMV between moderate and severe MS. Subjects and Methods: The immediate and long-term outcomes of 786 patients (198 male, mean age; 43 years) who underwent PMV at a single referral center, between 1988 and 2000, were analyzed. The clinical and echocardiographic data were compared between moderate (n=357) and severe MS (n=429). Results: Optimal results were gained in 618 (79%) patients, including 80 and 76% moderate and severe MS cases, respectively (p=0.13). Acute complications occurred in 85 patients (11%), but without significant difference between the two groups. After a mean follow-up period of 94 months (range, 6 to 210 month), the 5 year event-free survival rate was better in moderate (88%) than in severe MS (79%), but the 10 year event-free survival rates were no different (65% vs. 65%). Independent predictors for better prognosis were a lower echo score (≤8) (p=0.017, HR=0.67), a larger mitral valve area after the PMV (≥1.7 cm²) (p=0.002, HR=0.65), less mitral regurgitation (<grade III) (p=0.001, HR=0.46) and a lower left atrial pressure (<12 mmHg) (p=0.005, HR=0.80). Conclusion: The immediate and long-term outcomes of PMV for moderate MS were no better after 9 years than those for severe MS. Therefore, PMV for moderate MS should be considered in selected cases with a favorable MV morphology.