LETTER TO THE EDITOR
Predictors of left ventricular dysfunction following mitral valve repair for mitral regurgitation
Mohammed R. Essop, MD, FACC
Division of Cardiology, Baragwanath Hospital, P.O. Bertsham 2013, Johannesburg, South Africa
ressop{at}worldonline.co.za
We read the study by Matsumura et al. (1) and the accompanying editorial by Wisenbaugh (2) with great interest. Unfortunately, in developing countries, rheumatic heart disease remains the major cause for severe mitral regurgitation. Furthermore, many patients are seen for the first time when adverse echocardiographic characteristics such as an ejection fraction <60% or an end-systolic diameter >45 mm are already present. The results of mitral valve replacement under these circumstances have been clearly documented to be poor (3), and an often-asked question is whether mitral valve repair—although more difficult with rheumatic disease compared to degenerative disease—would not be preferable in these patients.
Although not stated clearly in the report or editorial, it would appear that the echocardiographic predictors of a poor outcome following mitral valve repair are numerically similar if not identical to those previously defined for mitral valve replacement. This is disappointing because given the well-known benefits of valve repair in terms of preservation of chordal-ventricular continuity, one would have anticipated that postoperative left ventricular (LV) function could be guaranteed at lower preoperative ejection fractions or higher end-systolic diameters.
Also of great interest, but not commented upon, is the fact that in a significant number of patients, postoperative ejection fraction was higher compared to the preoperative value (Fig. 1 in Matsumura et al. [1]). Although preservation of ejection-phase indices of LV function have been well documented with mitral valve repair, the apparent increase in ejection fraction noted by Matsumura et al. (1) is a less known phenomenon, especially as the greatest impact of any mitral valve surgery is an immediate and significant decline in the preload. A postoperative reduction in afterload has been documented in some studies of mitral valve repair (4,5) and is supported in the current study by a reduction in the end-systolic diameter. However, postoperative reduction in afterload in the studies by Lessana et al. (4) and Bonchek et al. (5) did not result in an increase in ejection fraction but was sufficient only to prevent a significant decline in the ejection fraction. A depressed preoperative contractile state, which may have improved with removal of chronic volume overload, is also unlikely as the majority of patients with improvement in ejection fraction had normal ejection fractions to begin with (6).
Finally, it would be of interest to know what proportion of patients had moderate mitral regurgitation, as most guidelines require that mitral regurgitation be considered significant before contemplating operative intervention.
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References
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- Matsumura T, Ohtaki E, Tanaka K, et al. Echocardiographic prediction of left ventricular dysfunction after mitral valve repair for mitral regurgitation as an indicator to decide the optimal timing of repair. J Am Coll Cardiol. 2003;42:458–463[Abstract/Free Full Text]
- Wisenbaugh T. Unexpected, dismal left ventricular dysfunction after surgery for mitral regurgitation. J Am Coll Cardiol. 2003;42:464–465[Free Full Text]
- Wisenbaugh T, Skudicky D, Sareli P. Prediction of outcome after valve replacement for rheumatic mitral regurgitation in the era of chordal preservation. Circulation. 1994;89:191–197[Abstract/Free Full Text]
- Lessana A, Herreman F, Boffety C, et al. Hemodynamic and cineangiographic study before and after mitral valvuloplasty. Circulation. 1981;64(Suppl II):195–201
- Bonchek LI, Olinger GN, Siegel R, et al. Left ventricular performance after mitral reconstruction for mitral regurgitation. J Thorac Cardiovasc Surg. 1984;88:122–130[Abstract]
- Wisenbaugh T. Does normal pump function belie muscle dysfunction in patients with chronic severe mitral regurgitation? Circulation. 1988;77:515–525[Abstract/Free Full Text]
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