Percutaneous mitral commissurotomy (PMC) is the alternative treatment of choice for mitral stenosis (MS). Its immediate and medium term results are comparable to those of surgical commissurotomy, however in the long term there is a risk of restenosis. The purpose of this study is to determine the factors predicting restenosis after PMC.

322 patients (66% women), average age: 35±3 years (9–75 years) having a tight MS and treated by PMC with Inoué balloon. The anatomic aspect of the mitral apparatus before PMC has been studied according to the criteria of the Wilkins score with a concomitant study of the state of mitral commissures. The primary success of PMC is defined as follows: mitral area (MA) post-PMC >1.5cm² and gain in MA >25% and mitral regurgitation (MR) ≤ grade 2. Mitral restenosis is defined as a MA <1.5cm² and/or loss>50% of initial gain in MA.

The rate of primary success of PMC was 86% and mean MA post PMC was 1.82±0.33cm² compared to MA pre-PMC of 1±0.18cm² (P<0.0001). Opening of two commissures has been observed in 74% of patients. After an average period of 62±32 months, only 12% of patients had a dyspnea stage III-IV of NYHA, MA was 1.64±0.3cm² (P<0.001) and mitral restenosis happened in 47 patients (20%) after a period of 60.48±27 months (22–124months). The independent predictors of mitral restenosis after a successful PMC were: previous surgical commisurotomy, Wilkins score>8, MA after PMC <1.8cm² and absence of bicommissural opening post PMC.

A favorable anatomy of mitral apparatus and the optimisation of immediate result of PMC are the guaranty for the maintenance of good result in the long term.