Background--Mild commissural mitral regurgitation (MR) is associated with significantly higher restenosis-free survival after percutaneous mitral valvuloplasty (PMV), which suggests that different mechanisms of significant MR after PMV may have different clinical courses. We therefore analyzed long-term prognostic factors of significant MR after PMV.

Methods and Results--Echocardiographic and clinical follow-up data on 380 patients were analyzed (286 women, mean age 44±11 years) who underwent PMV with the Inoue balloon technique between 1995 and 2000. Significant MR developed in 47 patients (12.4%). The survival rate at 8 years was 96±3% and 98±10% in patients with and without significant MR, respectively (P=0.084). The most frequent mechanism was commissural MR, or MR that originated at the site of successful commissurotomy, which occurred in 27 of 47 patients (57%), whereas noncommissural MR occurred in 20 (43%) patients, 12 (26%) with subvalvular damage resulting in chordae rupture and flail motion and 8 (17%) with leaflet laceration. The 8-year event-free survival rate was significantly lower in patients with significant MR than in those without (47±8% versus 83±3%, P<0.001) and was significantly higher in patients with commissural versus noncommissural MR (63±11% versus 29±11%, P<0.001). Of the 47 patients with significant MR, who were followed up for 74±29 months, 19 patients (40%) underwent mitral valve replacement, and 28 patients (60%) received medical treatment only. Patients with commissural MR had a significantly lower rate of mitral valve replacement than patients with noncommissural MR (15% versus 70%, P<0.001). Multivariate analysis showed that atrial fibrillation (odds ratio, 7.4; 95% CI, 1.1 to 56.4; P=0.038), mean mitral gradient immediately after PMV (odds ratio, 1.5; 95% CI, 1.1 to 2.0; P=0.009), and the mechanism of MR (odds ratio, 16.7; 95% CI, 2.3 to 122.2; P=0.005) were independent factors associated with mitral valve replacement.

Conclusions--Clinical outcome of patients with significant MR after PMV varied according to MR mechanism and the adequacy of hemodynamic improvement, which is easily assessed by echocardiography immediately after PMV.