Mitral Valve Repair vs Replacement
Abstracts & Commentary
Synopsis: Mitral valve repair is associated with reduced hospital length of stay and increased in-hospital and long-term survival compared to mitral valve replacement. However, these benefits are not seen in those older than 60 or those patients requiring concomitant CABG.
Sources: Thourani VH, et al. Circulation. 2003;108: 298-404; Enriquez-Sarano M, et al. Circulation. 2003; 108:253-256.
Although mitral valve repair for mitral regurgitation is gaining in popularity, there are little comparative data with mitral valve replacement. Thus, Thourani and colleagues performed a case-controlled observational study of the Emory University Hospitals surgical database, matching 625 patients undergoing mitral valve repair with 625 undergoing mitral valve replacement from 1984 to 1997. The presence of preoperative heart failure was higher in the mitral valve repair group as compared to the replacement group (56% vs 50%; P = .02), and more repair patients had a myxomatous valve (46% vs 39%; P < .001). Otherwise, the 2 groups were well matched. Almost all the patients had elective surgery (96%), and about 25% of both groups had concomitant coronary artery bypass graft (CABG) surgery. Crossover to replacement from repair during the initial hospitalization occurred in 47 of the 625 repair patients (7.5%). Hospital length of stay was significantly less in the mitral repair group (9.5 vs 12.3 days; P < .001), and in-hospital mortality was less in the repair group (4.3% vs 6.9%; P < .05). Overall, 10-year survival was higher in the repair group (62% vs 46%; P < .001). Survival at 10 years in those younger than 60 was higher with mitral valve repair (81% vs 55%; P < .001) but was not significantly different in those older than 60 (33% vs 36%). Survival at 10 years for those who had concomitant CABG was not significantly different in those with mitral repair vs replacement (28% vs 34%). Freedom from subsequent mitral valve replacement was higher in mitral valve repair patients (78% vs 66%; P < .001). The strongest multivariate correlates with long-term mortality were mitral replacement and left ventricular dysfunction. Thourani et al concluded that mitral valve repair is associated with reduced hospital length of stay and increased in-hospital and long-term survival compared to mitral valve replacement. However, these benefits are not seen in those older than 60 or those patients requiring concomitant CABG.
Comment by Michael H. Crawford, MD
The potential benefits of mitral valve repair for significant mitral regurgitation are lower risk of thromboembolism, and hence, less need for anticoagulation, and better preservation of left ventricular function as compared to mitral valve replacement. This study adds the information that not only operative mortality, but also long-term mortality, is reduced by repair as compared to replacement. However, they found that these benefits did not extend to patients older than 60 or with concomitant CABG. This conclusion is at variance with other studies where the benefits were more uniformly observed. The accompanying editorial is authored by representatives from the Mayo Clinic who have published their experience and disagree with the investigators on the exclusivity of the benefits. They point out that this study included a higher proportion of patients with rheumatic heart disease (25%) than is seen in US series. Such patients are difficult to repair when they are older. They also pointed out that many of the patients in this study may have had ischemic heart disease, where mitral valve repair is not known to be of benefit. Another problem with the study is that since it spanned more than 20 years, the earlier patients may have gotten more bioprosthetic valves before their limited durability was shown in long-term trials only recently published. Currently, most patients would receive a mechanical valve unless anticoagulation was contraindicated or not desired. Although some of these critiques may influence the interpretation of the study, it is a valuable addition to our knowledge base and shows the superiority of mitral valve repair for mitral regurgitation. Thus, whenever feasible, mitral valve repair should be recommended and patients sent to centers with experience with this technically challenging procedure. Naturally, younger patients with myxomatous valves will be expected to do very well, but repair should not be automatically denied to older patients with rheumatic or ischemic mitral regurgitation. These patients require careful evaluation, and perhaps surgery should be reserved for those with symptoms clearly due to their mitral regurgitation.
Dr. Crawford, Professor of Medicine, Associate Chief of Cardiology for Clinical Programs, University of California, San Francisco, is Editor of Clinical Cardiology Alert.
Although mitral valve repair for mitral regurgitation is gaining in popularity, there are little comparative data with mitral valve replacement. Thus, Thourani and colleagues performed a case-controlled observational study of the Emory University Hospitals surgical database, matching 625 patients undergoing mitral valve repair with 625 undergoing mitral valve replacement from 1984 to 1997.
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