Mitral valve rupture following percutaneous mitral commissurotomy: existence of predictive factors

The purpose of this study was to describe the mechanism and determine predictive factors of mitral valve rupture requiring valve replacement following percutaneous mitral commissurotomy. Of the 350 consecutive patients treated by balloon mitral commissurotomy, the procedure was not completed in 16, and 11 developed acute severe mitral rgurgitation requiring valve replacement: seven cases of anterior leaflet rupture, three cases of posterior leaflet rupture and one case of anterior chordal surface. These 27 group I patients were compared to the remaining 323 (group II) in whom the procedure was completed. The 11 excised valves were evaluated by an experienced pathologist. Eight of the 11 patients had an echo cardiographic score <8 (mean score 6.5 ± 1), no valvular calcification at X-ray and double balloon percutaneous mitral commissurotomy. Microscopy in six patients showed focal fibrous thickening at the site of the rupture but no calcification. One patient developed severe mitral régurgitation due to chordal rupture with an Inoue balloon. The two remaining patients had an echo score of ten and valve calcification on X-ray. Microscopy revealed severe homogeneous chronic rheumatic mitral disease. In one of these two patients, leaflet rupture was related to an ‘oversized balloon’ (2 × 19 mm + 15 mm). Statistical analysis showed only echo score differences between the two groups (6.9 ± 1.4 in group I vs 8.2 ±1.6 in group II, P<0.02). Valves were less calcified and more mobile in group I than in group II (calcification and mobility echo score 1.3 ± 0.8 vs 1.8 ± 0.9, P<0.08, 1.9 ± 0.5 vs 2.2 ± 0.5, P<0.03 respectively). Leaflet rupture following percutaneous mitral commissurotomy is rare (3%) and seems to occur in patients with mobile, non-calcified stenotic mitral valves with heterogenous rheumatic changes and unexpected abundant myxoid connective tissue. Leaflet rupture requiring urgent valve replacement is a rare, unpredictable complication of percutaneous mitral commissurotomy and can occur in young patients with low echo scores.