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 n ot completed in 16, and 11 developed acute severe mitral regurgitation requiring valve replacement: seven cases of anterior leaflet rupture, three cases of posterior leaflet rupture and one case of anterior cho rdal surface. These 27 group I patients were compared to the remaining 323 (group II) in whom the procedure was completed. The II excised va lves were evaluated by an experienced pathologist. Eight of the II pat ients had an echocardiographic score <8 (mean score 6.5 +/- Il, no val vular calcification at X-ray and double balloon percutaneous mitral co mmissurotomy. Microscopy in six patients showed focal fibrous thickeni ng at the site of the rupture but no calcification. One patient develo ped severe mitral regurgitation due to chordal rupture with an Inoue b alloon. 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 ruptu re was related to an 'oversized balloon' (2 x 19 mm + 15 mm). Statisti cal 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 (calc ification 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 w ith heterogenous rheumatic changes and unexpected abundant myxoid conn ective tissue. Leaflet rupture requiring urgent valve replacement is a rare, unpredictable complication of percutaneous mitral commissurotom y and can occur in young patients with low echo scores.