Relationship between papillary muscle size and benefit to cardiac functionin mitral valve replacement with chordal preservation

Background and aim of the study: Mitral valve replacement (MVR) with chorda l 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 s tudy 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 siz e 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-sectiona l area was measured in each patient, as well as postoperative fractional sh ortening (FS) of the septo-lateral, anteroposterior and vertical dimensions of the left ventricle. The technique of preserving all chordae tendineae i nvolved reattaching the anterior leaflet chordae to the mitral annulus near each commissure. Results: Postoperative FS of the septolateral and anteroposterior dimension s was better in patients with chordal preservation than in those without. I n the former subgroup, a larger PM was associated with better FS of the lef t 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 ver tical dimensions. This discrepancy in the relationship between PM size and functional benefits among the three dimensions may be related to the direct ion in which the PMs are suspended in our technique, or its effect on regio nal left ventricular function. Conclusion: The present study indicated that PM size may be used as a facto r to better predict the outcome of MVR with chordal preservation.