Relationship between papillary muscle size and benefit to cardiac function in mitral valve replacement with chordal preservation.

BACKGROUND AND AIM OF THE STUDY Mitral valve replacement (MVR) with chordal preservation in patients with chronic mitral regurgitation (MR) has been reported to maintain systolic function of the left ventricle. However, the benefits of MVR with chordal preservation are not always predictable. The study aim was to ascertain the influence that papillary muscle (PM) size has on cardiac function after MVR with chordal preservation. METHODS Postoperative regional shortening and its relationship with PM size were investigated by two-dimensional echocardiography in 18 patients who underwent MVR with chordal preservation, and nine patients without chordal preservation between 1986 and 1998 at Tenri Hospital. The PM cross-sectional area was measured in each patient, as well as postoperative fractional shortening (FS) of the septolateral, anteroposterior and vertical dimensions of the left ventricle. The technique of preserving all chordae tendineae involved reattaching the anterior leaflet chordae to the mitral annulus near each commissure. RESULTS Postoperative FS of the septolateral and anteroposterior dimensions was better in patients with chordal preservation than in those without. In the former subgroup, a larger PM was associated with better FS of the left ventricle in the septolateral dimension (anterior PM, p <0.001, r = 0.78; posterior PM, p = 0.0010, r = 0.69), but not in the anteroposterior or vertical dimensions. This discrepancy in the relationship between PM size and functional benefits among the three dimensions may be related to the direction in which the PMs are suspended in our technique, or its effect on regional left ventricular function. CONCLUSION The present study indicated that PM size may be used as a factor to better predict the outcome of MVR with chordal preservation.