An artificial mitral valve after removal.
Mitral valve replacement has been superseded by mitral valve repair as the treatment of choice for all forms of mitral regurgitation. There are several reasons to prefer a mitral valve repair to a replacement (such as avoidance of anticoagulation, lower risk of endocarditis, better ventricular function, desire to keep one’s own tissue), but from an epidemiological viewpoint, the prime value of the repair operation lies in the incontrovertible superior long term outcomes of repair relative to replacement. Almost all studies comparing valve repair and replacement for regurgitation have found a survival benefit for repair in a diverse array of clinical settings. Specific to degenerative disease, Enriquez-Sarano and colleagues1 over a decade ago compared a cohort of 195 repairs (170 degenerative) to 214 replacements (141 degenerative) and found a 11% survival benefit with repair at 10 years (Figure 18). Although this study was confounded by a high number of non-degenerative patients in the replacement group, multivariate analysis showed a beneficial effect of repair on survival. Specifically looking at degenerative patients, Lee and colleagues2 found a 12% survival benefit at six years of repair over replacement, the main advantage coming from reduced heart-failure related mortality. In the setting of coexisting coronary artery disease requiring concurrent bypass surgery, there is also a benefit of mitral valve repair over replacement for degenerative disease3. Because of the general preference of repair over replacement since the 1990s, there are no recent cohorts that allow comparison of outcomes as there is surgeon or selection bias in patients ending up with repair or replacement.
Figure 1: Survival after mitral valve repair or replacement compared with expected survival. Numbers below indicate patients at risk.*
(1) Enriquez-Sarano M, Schaff HV, Orszulak TA, Tajik AJ, Bailey KR, Frye RL. Valve repair improves the outcome of surgery for mitral regurgitation. A multivariate analysis. Circulation 1995 February 15;91(4):1022-8.
(2) Lee EM, Shapiro LM, Wells FC. Superiority of mitral valve repair in surgery for degenerative mitral regurgitation. Eur Heart J 1997 April;18(4):655-63.
(3) Gillinov AM, Faber C, Houghtaling PL et al. Repair versus replacement for degenerative mitral valve disease with coexisting ischemic heart disease. J Thorac Cardiovasc Surg 2003 June;125(6):1350-62.
(*) Modified from Enriquez-Sarano M, Schaff HV, Orszulak TA, et al: Valve repair improves the outcome of surgery for mitral regurgitation. A multivariate analysis. Circulation 91(4):1022-8 1995. Lippincott Williams & Wilkins