Effect of aortic valve replacement for aortic stenosis on severity of mitral regurgitation.

BACKGROUND: Surgically addressing moderate mitral regurgitation (MR) at the time of aortic valve replacement (AVR) for aortic stenosis remains uncertain. The purpose of this study was to examine the change in moderate (2+) or moderate-severe (3+) MR after isolated AVR for aortic stenosis to determine preoperative factors predictive of improvement in MR.
METHODS: Using an institutional databank of prospectively collected data, all patients undergoing isolated AVR for aortic stenosis with moderate (2+) to moderate-severe (3+) MR between 1994 and 1996 at the Montreal Heart Institute were evaluated.
RESULTS: Eighty patients with preoperative and postoperative transthoracic echocardiographic follow-up were identified. Preoperative MR was moderate (2+) in 78 patients (97.5%) and moderate-severe (3+) in 2 patients (2.5%). Mitral regurgitation was classified as rheumatic (32%), ischemic (32%), functional (21%), and myxomatous (15%). At 1-year follow-up transthoracic echocardiography, MR improved by 1 or 2 grades in 29 patients (35%), was unchanged in 44 (55%), and worsened in 7 (10%). On multivariate analysis, isolated ischemic and functional MR were the only preoperative factors predictive of MR improvement after AVR (p = 0.01): 54% of ischemic and 44% of functional MR patients showed improvement in MR after AVR compared with 23% of rheumatic and 17% of myxomatous MR patients.
CONCLUSIONS: Etiology of MR was a significant prognostic factor for improvement in MR grade. Since there was little improvement in the rheumatoid and myxomatous group, replacement or repair should strongly be considered. For functional and ischemic mitral regurgitation, a surgical correction should be performed on an individual basis.