Serial echocardiographic evaluation of restenosis after successful percutaneous mitral commissurotomy

OBJECTIVES: This study was designed to determine predictors of restenosis after successful percutaneous mitral commissurotomy (PMC) and its relationship to late clinical outcome. BACKGROUND: The restenosis rate after PMC and its relationship to late clinical outcome is poorly defined. METHODS: Serial echocardiography was performed in 310 patients who underwent PMC. Restenosis, defined as mitral valve area (MVA) <1.5 cm² and ≥50% loss of initial MVA increase, was determined by both two-dimensional (2D) and Doppler echocardiography. Clinical, echocardiographic and cardiac catheterization variables were evaluated to determine predictors of restenosis. The relationship between restenosis and major adverse clinical events (death, repeat PMC or mitral valve replacement) and functional status was assessed. RESULTS: Acute procedural success occurred in 206 patients (66%), who were then followed for restenosis. The cumulative restenosis rate was approximately 40% at six years after successful PMC (44% by 2D and 40% by Doppler MVA). The only independent predictor of restenosis was echocardiographic score (restenosis at five years was 20% for score >8 vs. 61% for score ≥8, p < 0.001). The decline in MVA and occurrence of restenosis was gradual and progressive during the follow-up period. Procedural results and baseline factors predicted event-free survival. Restenosis by 2D MVA was related to adverse events or New York Heart Association functional class 3 to 4 symptoms, but restenosis was not an independent predictor of clinical outcome by multivariate analysis. CONCLUSIONS: Restenosis is a common, gradual and progressive occurrence after successful PMC and is predicted by higher echocardiographic score. Restenosis is related to late adverse clinical outcome, though clinical outcome remains best predicted by the acute procedural results of PMC.