Mitral regurgitation after percutaneous mitral valvotomy

Mitral regurgitation (MR) after percutaneous mitral balloon valvotomy (PMV) is commonly an end point and may be a significant complication. Some incre ase irt MR occurs in more than half of patients undergoing PMV. An increase > 2 grades occurs in 3%-15% of patients, and < 5% have severe MR as a comp lication. MR is a significant predictor for late cardiac events and preexis ting MR before PMV is also associated with poor late outcome. Mild increase s in MR are due to stretching of the annulus, excess commissural tearing, o r papillary muscle trauma. Mild MR frequently disappears at follow-up and r arely increases, Risk factors for development of MR have varied among multi ple studies. Balloon oversizing and entrapment/tearing of chordae by the ba lloon(s) are mechanical factors. Most predictors are related to the patholo gic anatomy of the mitral valve. Older age, a larger end-systolic volume in dex, and lower ejection fraction may be independent predictors of progressi on of MR. Subvalvular disease and valve thickening have also been identifie d as predictors. A recently described "scoring" system for predicting MR co nsiders the distribution of anterior and posterior leaflet thickening, exte nt of commissural calcification/fibrosis, and degree of subvalvular disease . "Even" calcification/thickening produces a "lower" or "better" score than "uneven" distribution. Bicommissural calcification and thickening and shor tening of chordae all predict bad outcome. Thus careful echocardiographic e valuation of mitral valve pathoanatomy pre-PMV can identify most predictors of the development of MR.