Background and Objectives:Percutaneuous transvenous mitral commissurotomy (PTMC) has been performed as an effective non-surgical treatment modality of rheumatic mitral stenosis. Mitral regurgitation (MR) as a complication of the procedure occur in 20~53% of the patients. The moderate to severe mitral reguargitation, created by the PTMC, sometimes leads to the requirement for mitral valve replacement, but most of the MR limits the optimal dilation of mitral commissure due to the worry about the progression of the MR. This study was designed to evaluate the occurrence of mitral regurgitation and predictive factors for the moderate to severe mitral regurgitation (grade≥2) induced by PTMC. Methods:This study enrolled 46 patients (female 42, mean age 45 years) who have performed PTMC in Yeungnam University Hospital from May 1996 to May 1999. We analyzed the occurrence rate of mitral regurgitation (MR) and predictive factors for MR grade≥2 after procedure. Results:MR was detected in 35% of the patients prior PTMC, and in 56% after the procedure (grade 1, 30%;grade 2, 15%;grade 3, 11%). 21 cases of the MR was commissure MR as a grade≤2. MR grade 3, occured in 5 patients, was non-commissure MR caused by the unilateral rupture of the lateral commissure in 4 patients and tearing of the annulus in one patient. On the univariate analysis, patients with MR grade≥2 showed more frequent atrial fibrillation, mitral regurgitation and fluoroscopic calcification, and had more severe symptoms than patients with MR grade<2 before the procedure. On the analysis of the calcification, there was no significant difference of the leaflet calcification score, but the commissure calcification score was significantly higher in MR≥2 group than MR<2 group (1.5±0.54 vs 2.5±0.96, p=0.02). On the multivariate logistic regression analysis, independent predictor of MR grade≥2 was fluoroscopic mitral calcification (OR 6.38, p= 0.048). Conclusion:Mild to moderate commissure MR was observed in most of the patients after PTMC. Commissure calcification have more influence on the development of MR grade≥2 than valvular calcification, and the fluoroscopic mitral calcification can predict the occurrence of MR grade≥2 mitral regurgitation after PTMC. (Korean Circulation J 2000;30(9):1125-1232)