Effect of concurrent mitral valve surgery for secondary mitral regurgitation upon mortality after aortic valve replacement or coronary artery bypass surgery

Abstract

Objectives: It is uncertain whether concurrent mitral valve repair or replacement for moderate or greater secondary mitral regurgitation at the time of coronary artery bypass graft or aortic valve replacement surgery improves long-term survival.

Methods: Patients undergoing coronary artery bypass graft and/or aortic valve replacement surgery with moderate or greater secondary mitral regurgitation were reviewed. The effect of concurrent mitral valve repair or replacement upon long-term mortality was assessed while accounting for patient and operative characteristics and mitral regurgitation severity.

Results: Of 1,515 patients, 938 underwent coronary artery bypass graft or aortic valve replacement surgery alone and 577 underwent concurrent mitral valve repair or replacement. Concurrent mitral valve repair or replacement did not alter the risk of postoperative mortality for patients with moderate mitral regurgitation (hazard ratio = 0.93; 0.75-1.17) or more-than-moderate mitral regurgitation (hazard ratio = 1.09; 0.74-1.60) in multivariable regression. Patients with more-than-moderate mitral regurgitation undergoing coronary artery bypass graft-only surgery had a survival advantage from concurrent mitral valve repair or replacement in the first two postoperative years (P = 0.028) that did not persist beyond that time. Patients who underwent concurrent mitral valve repair or replacement had a higher rate of later mitral valve operation or reoperation over the five subsequent years (1.9% vs. 0.2%; P = 0.0014) than those who did not.

Conclusions: These observations suggest that mitral valve repair or replacement for more-than-moderate mitral regurgitation at the time of coronary artery bypass grafting may be reasonable in a suitably selected coronary artery bypass graft population but not for aortic valve replacement, with or without coronary artery bypass grafting. Our findings are supportive of 2021 European guidelines that severe secondary mitral regurgitation "should" or be "reasonabl[y]" intervened upon at the time of coronary artery bypass grafting but do not support 2020 American guidelines for performing mitral valve repair or replacement concurrent with aortic valve replacement, with or without coronary artery bypass grafting.

Keywords: aortic valve surgery; coronary artery bypass surgery; guidelines; mitral regurgitation; mitral valve surgery; mortality; outcomes; survival.

Figure 1

PRISMA diagram. There are two patient exclusion steps. The first step excludes patients not eligible by operative, valvular, or surgical criteria. The second step excludes patients with less-than-moderate severity of mitral regurgitation on both preoperative TTE and intraoperative TEE.

Figure 2

Kaplan–Meier plot of survival of 501 patients undergoing AVR who underwent MVR/P or not, stratified by the worst measured severity of MR. Observed mortality is stratified by the source of the most severe grade of MR (moderate, >moderate) and whether or not MVR/P was concurrently performed. Pairwise comparison of survival between AVR patients with moderate MR who underwent MVR/P or did not showed no statistical significance (P = 0.31) after adjustment for two comparisons. Pairwise comparison of survival between patients with more-than-moderate MR who underwent MVR/P or did not showed no statistical significance (P = 0.063) after adjustment for two comparisons.

Figure 3

Kaplan–Meier plot of survival of 672 patients undergoing CABG who underwent MVR/P or not stratified by the worst measured severity of MR. Observed mortality is stratified by the source of the most severe grade of MR (moderate, >moderate) and whether or not MVR/P was concurrently performed. Pairwise comparison of survival between CABG patients with moderate MR who underwent MVR/P or did not showed no statistical significance (P = 0.49) after adjustment for two comparisons. Pairwise comparison of survival between patients with more-than-moderate MR who underwent MVR/P or did not showed statistical significance when adjusted for two comparisons (P = 0.028), which was explained by mortality in the first 2 postoperative years.

Figure 4

Kaplan–Meier plot of survival of 345 patients undergoing AVR/CABG who underwent MVR/P or not stratified by the worst severity of MR. Observed mortality is stratified by the source of the most severe grade of MR (moderate, >moderate) and whether or not MVR/P was concurrently performed. Pairwise comparison of survival between AVR/CABG patients with moderate MR who underwent MVR/P or did not showed no statistical significance (P = 0.15) after adjustment for two comparisons. Pairwise comparison of survival between patients with more-than-moderate MR who underwent MVR/P or did not showed no statistical significance (P = 0.55) after adjustment for two comparisons.