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Mitral valve repair has been suggested as providing a better postoperative outcome than valve replacement for mitral regurgitation, but this impression has been obscured by differences in baseline characteristics and has not been confirmed in multivariate analyses.
Valve Repair Improves the Outcome of Surgery for Mitral Regurgitation A Multivariate Analysis Maurice Enriquez-Sarano, Hartzell V Schaff, Thomas A Orszulak, A Jamil Tajik, Kent R Bailey, Robert L Frye https://doi.org/10.1161/01.CIR.91.4.1022 Circulation 1995;91:1022-1028 Originally published February 15, 1995 Article Figures & Tables Info & Metrics eLetters Abstract Background Mitral valve repair has been suggested as providing a better postoperative outcome than valve replacement for mitral regurgitation, but this impression has been obscured by differences in baseline characteristics and has not been confirmed in multivariate analyses Methods and Results The outcomes in 195 patients with valve repair and 214 with replacement for organic mitral regurgitation were compared using multivariate analysis All patients had preoperative echocardiographic assessment of left ventricular function Before surgery, patients with valve repair were less symptomatic than those with replacement (42% in New York Heart Association functional class I or II versus 24%, respectively; P=.001), had less atrial fibrillation (41% versus 53%; P=.017), and had a better ejection fraction (63±9% versus 60±12%, P=.016) After valve repair, compared with valve replacement, overall survival at 10 years was 68±6% versus 52±4% (P=.0004), overall operative mortality was 2.6% versus 10.3% (P=.002), operative mortality in patients under age 75 was 1.3% versus 5.7% (P=.036), and late survival (in operative survivors) at 10 years was 69±6% versus 58±5% (P=.018) Late survival after valve repair was not different from expected survival After surgery, ejection fraction decreased significantly in both groups but was higher after valve repair (P=.001) Multivariate analysis indicated an independent beneficial effect of valve repair on overall survival (hazard ratio, 0.39; P=.00001), operative mortality (odds ratio, 0.27; P=.026), late survival (hazard ratio, 0.44; P=.001), and postoperative ejection fraction (P=.001) Conclusions Valve repair significantly improves postoperative outcome in patients with mitral regurgitation and should be the preferred mode of surgical correction The low operative mortality is an incentive for early surgery before ventricular dysfunction occurs mitral valve prognosis ventricles myocardium surgery Since the early days of cardiac surgery,1 the repair of regurgitant mitral valves has been pioneered with the perception that maintaining the normal architecture of the mitral valve is beneficial to the patient.5 However, the clinical suggestion that valve repair, compared with valve replacement, improves postoperative survival6 10 11 and left ventricular function1213 14 has been obscured by differences in baseline characteristics among the patients treated by the two methods14 15 16 17 and has not been confirmed by multivariate analysis.15 16Moreover, comparison between repair and replacement has been hindered by the limited number of repairs involved15 16 and by the failure to consider important predictors of outcome such as preoperative left ventricular function.18 19 20 Thus, the clinical impact of valve repair has remained uncertain as has, therefore, its potential as the preferred surgical method of correction of mitral regurgitation Accordingly, we examined the outcome after valve repair and valve replacement in patients with mitral regurgitation in whom preoperative left ventricular function could be assessed echocardiographically, having hypothesized that mitral valve repair improves operative mortality, late survival, and postoperative residual left ventricular function compared with mitral valve replacement Methods The present study was based on a review of our experience with valve repair and valve replacement for the surgical correction of mitral regurgitation Included in the study were patients who had repair or replacement of the mitral valve performed between January 1, 1980, and December 31, 1989; who had acquired organic mitral regurgitatiorepair and replacement groups No significant difference is observed Discussion In the present series of 195 valve repairs and 214 valve replacements performed for organic mitral regurgitation, there are differences in baseline characteristics between the two groups, but multivariate analysis confirms that valve repair is an independent determinant of improved operative and late survival and of improved left ventricular function Beneficial Results of Valve Repair Compared With Valve Replacement In patients with mitral stenosis, conservative surgery—that is, commissurotomy— provides both low operative risk and excellent late survival, with a low incidence of valve-related complications.28 These results are at variance with those obtained with valve replacement.29Thus, in this setting, conservative surgery, if feasible, has always been the preferred option Conservative surgery (valve repair) has also been attempted for mitral regurgitation since the early days of cardiac surgery, but the results have been more inconsistent30 31 32 33because the lesions of mitral regurgitation are more complex and difficult to correct.34 The techniques of repair of regurgitant lesions have progressively improved,35 36 and with the decrease in rheumatic valve disease37 they are now widely applied in the large population with degenerative mitral valve disease.10 37 38 39 40 The durability of valve repair also has been well demonstrated.41 42 43 However, valve repair can be difficult,44 and its superiority to prosthetic replacement has not been firmly established15 16 44 45 because of small sample sizes45 and of differences in baseline characteristics of patients14 15 16 17 that suggest that surgery was performed at an earlier stage in valve repair than in valve replacement It has remained uncertain, therefore, whether the observed differences in outcome are related to the method of correction of the mitral regurgitation or to a more favorable clinical situation existing before surgery Matching identical patients who have had either valve repair or replacement has been attempted,19 45but this method is selective and has its drawbacks Thus, the best way of addressing the issue of nonuniformity of the groups is to perform multivariate analyses that include the most important prognostic indicators When this type of analysis was performed in other studies, however, it did not show a significant independent prognostic impact of valve repair.15 16 In contrast, the present study demonstrates that the method of correction is indeed an independent determinant of the observed differences in survival after valve repair in comparison with valve replacement The large number of repairs, the homogeneity of the patient population, and the preoperative assessment of left ventricular function probably contribute to the statistical power of the present series Mechanism of Improved Outcome The lower operative mortality after valve repair in the present study is consistent with previous observations,9 but the mechanism has not been fully understood However, since left ventricular dysfunction is the major cause of late death after mitral valve surgery,46 the lower mortality rate in patients with valve repair is readily understandable: after valve repair, postoperative ejection fraction is significantly higher than after valve replacement, and the incidence of death due to left ventricular dysfunction is reduced Although this phenomenon is in part related to a better preoperative function, it also is an intrinsic effect of valve repair Improvement in left ventricular function was previously suggested, mainly on the basis of small series,13 14 but in the present study, postoperative echocardiograms were available in 315 of the 409 patients to conclusively confirm this improvement The role of the conservation of the normal mitral apparatus architecture in the preservation of left ventricular function has been underlined experimentally47 48 as well as clinically,14 49 50 51even in association with mitral valve replacement The better postoperative left ventricular function is not related to a higher left ventricular mass in patients with valve repair.52 Instead, it has been suggested that the geometry of the left ventricle is more favorable25 in association with conservation of the mitral architecture, leading to a reduction in wall stress that may allow more favorable remodeling of the ventricle after correction of the regurgitation It is to be noted, however, that ejection fraction decreases after valve repair53 and that the difference with valve replacement is only a matter of the magnitude of the left ventricular response to surgery Thus, the ability to perform valve repair should not allow one to disregard a potential left ventricular dysfunction This complication is associated with poor postoperative prognosis18 19 46 and is not eradicated by performance of valve repair The prognostic value of the preoperative echocardiographic ejection fraction is significant in patients with valve repair as well as in those with valve replacement20 and should be taken into account in the clinical decision-making process The improved outcome after valve repair is not obtained at the expense of an increase in valve-related complications In particular, the incidence of reoperation does not significantly differ between valve repair and replacement Furthermore, the incidence of significant hemorrhage is decreased with valve repair, another feature explaining the lower number of valve-related deaths New improvements should extend the field of application of mitral valve repair Artificial chordae and transposition of chordae35 36 are now available for flail anterior leaflets, which were, until recently, more difficult to repair than flail posterior leaflets Also, the addition of intraoperative transesophageal echocardiography has made it possible to detect, and immediately correct, unsatisfactory repairs.54 55 Potential Limitations The use of echocardiography may raise concern However, all the reported measurements were directed by two-dimensional echocardiography, and the assessment of ejection fraction by this methodology has not only been validated23 24 but also has shown acceptable correlations to angiography in our routine experience, and the high degree of reproducibility56and the value of the visual estimate57 58 have been confirmed Moreover, the most significant test of validity of a technique resides in its prognostic power In patients with mitral regurgitation, echocardiographic ejection fraction is the most powerful predictor of postoperative left ventricular function46 and survival.20 After surgery, the paradoxic septal motion associated with cardiac surgery has been shown to be a translational movement59rather than a regional wall motion abnormality, and it does not impair the ability to assess postoperative left ventricular function by echocardiography Furthermore, the postoperative left ventricular function shows no systematic trend for improvement or deterioration with time,46 and consequently the timing of measurement of the postoperative ejection fraction does not have an impact on the results and on the fact that postoperative left ventricular function is better preserved after valve repair than after replacement The fact that not all patients could have an assessment of postoperative ejection fraction has been encountered even in prospective studies,18 but these patients were similar to the patients without postoperative echocardiograms and thus were representative of the overall population in the present study The fact that baseline characteristics are different between the two groups of patients may be considered a limitation but is the precise reason why the superiority of valve repair over valve replacement remained uncertain.15 16 Because a randomized trial has never been performed and may not be feasible, the only presently acceptable method of comparison of the two surgical procedures is to adjust for the baseline outcome predictors in multivariate analysis, as was performed in the present study Clinical Implications The present series of 195 valve repairs and 214 valve replacements shows that after adjustment for all confounding variables, valve repair is a strong independent predictor of improved survival and postoperative left ventricular function, without compromise of the valvular results, in comparison with valve replacement These data suggest that valve repair should be the preferred method of correction of mitral regurgitation and should be considered in all cases in which surgery is contemplated The low operative risk of valve repair is an incentive to consider surgery at an early stage in the course of the disease before the advent of left ventricular dysfunction Acknowledgments We acknowledge the expert secretarial assistance of Janet L Halling, the data abstracting of Kim D Jones, and the data analysis of Sara L Fett in the preparation of this manuscript Footnotes Reprint requests to Maurice Enriquez-Sarano, MD, Mayo Clinic, 200 First St SW, Rochester, MN 55905 Received May 11, 1994 Revision received August 2, 1994 Accepted September 13, 1994 Copyright © 1995 by American Heart Association ... of our experience with valve repair and valve replacement for the surgical correction of mitral regurgitation Included in the study were patients who had repair or replacement of the mitral valve. .. incentive for early surgery before ventricular dysfunction occurs mitral valve prognosis ventricles myocardium surgery Since the early days of cardiac surgery, 1 the repair of regurgitant mitral. .. surgery (valve repair) has also been attempted for mitral regurgitation since the early days of cardiac surgery, but the results have been more inconsistent30 31 32 33because the lesions of mitral