Impact of degree of commissural opening after percutaneous mitral commissurotomy on long-term outcome.

OBJECTIVES: We sought to evaluate the prognostic value of the degree of commissural opening (CO) on outcome.

BACKGROUND: Commissural opening is the main mechanism by which the mitral valve area (MVA) increases after percutaneous mitral commissurotomy (PMC) but its impact on long-term outcome has never been evaluated.

METHODS: Of 1,024 consecutive patients with severe MS who underwent PMC, degree of CO was prospectively evaluated in 875 patients (age 48 +/- 13 years, female 83%, New York Heart Association (NYHA) functional class III/IV 75%) with good immediate PMC results (MVA >or=1.5 cm(2) and no mitral regurgitation >2/4). These 875 patients were divided into 3 groups: both commissures only partially opened or not split (Group 1, n = 189), 1 commissure completely split (Group 2; n = 459), and both commissures completely split (Group 3; n = 227). During a follow-up of 55 +/- 28 months, following clinical end points were collected: death, cardiovascular death, need for mitral valve surgery or repeat dilation, and NYHA functional class.

RESULTS: Before PMC, patients in Group 1 were older, more often in NYHA functional class III/IV, but MVA and mean gradient were not different (p >or= 0.50). Immediately after PMC, there were significant differences between groups with regard to mean gradient (Group 1, 5.1 +/- 2.1 mm Hg; Group 2, 4.5 +/- 1.7 mm Hg; Group 3, 4.0 +/- 1.6 mm Hg; p < 0.0001) and MVA (Group 1, 1.8 +/- 0.2 cm(2); Group 2, 1.9 +/- 0.2 cm(2); Group 3, 2.1 +/- 0.3 cm(2); p < 0.0001). The 10-year rate of good functional results (survival without need for mitral surgery or repeat dilation and NYHA functional class I or II at last follow-up) was significantly higher in Group 3 (76 +/- 5%) than in Groups 1 and 2 (39 +/- 8% and 57 +/- 11%, respectively; p < 0.0001). In multivariable analysis, either the degree of CO or the MVA was an independent predictor of good late functional results (p < 0.05).

CONCLUSIONS: Complete CO is associated with larger MVA, smaller gradients, and functional improvement. The degree of CO provides important prognostic information and thus should be systematically evaluated during and after PMC and considered as a complementary measure of the procedural success in addition to the MVA, not always easy to assess.