Importance of preserving the mitral subvalvular apparatus in mitral valve replacement

Background. This clinical study sought to determine whether mitral valve replacement (MVR) with the preservation of both anterior and posterior chordae tendineae (MVR group II) would be more effective on the improvement of left ventricular regional wall motion than MVR with the preservation of posterior chordae tendineae alone (MVR group I). Methods. Postoperative left ventricular wall motion was analyzed by a centerline method in three groups of MVR-group I (n = 13), group II (n = 15), and repair group (n = 15)-for mitral regurgitation. Shortening fraction of chordal length was determined in 100 chords, and these chords were divided into five regions. Results. The comparison of postoperative versus preoperative shortening fraction among the three groups revealed that postoperative wall motion improved more strikingly at apical and diaphragmatic regions in the MVR group II and repair group in comparison to the MVR group I. The postoperative shortening fraction at the apical region in the MVR group II was significantly increased in comparison to preoperative shortening fraction (preoperative, 3.68% +/- 1.87%; postoperative, 5.38% +/- 2.33%; p < 0.05). However, postoperative shortening fraction in cardiac base was decreased in the MVR group II as well as other two groups. Conclusions. The MVR with the preservation of both anterior and posterior chordae tendineae contributed to the improvement of left ventricular regional wall motion in the apical and diaphragmatic regions.