Background: The ideal surgical approach to moderate mitral regurgitation (MR) at the time of aortic valve replacement (AVR) for aortic stenosis (AS) remains uncertain. The purpose of this study was to examine the change in moderate (2+) to moderate-severe (3+) MR following isolated AVR for AS to determine preoperative factors predictive of improvement in MR
Methods: Using an institutional databank of prospectively collected data, all patients undergoing isolated AVR for AS with moderate (2+) to moderate-severe (3+) MR between 2000 and 2004 at the Montreal Heart Institute were evaluated.
Results: 80 patients (mean age 66±11 years; men / women: 42 / 38) with complete preoperative and postoperative transthoracic echocardiographic (TTE) follow-up were identified. Preoperative MR was moderate (2+) in 78 (97.5%) and moderate-severe (3+) in 2 (2.5%) patients. MR was classified as rheumatic (32%), ischemic (32%), functional (21%) and myxomatous (15%). Concomitant CABG was performed in 31% of patients. 44 patients had a patient-prosthesis mismatch (EOAi <0,85 cm2/m2). At follow-up TTE, MR improved by 1 or 2 grades in 29 patients (36%), was unchanged in 44 (55%) and worsened in 7 (10%). Improvement in MR was statistically significant (p<0.001). On multivariate analysis, isolated ischemic and functional MR were the only preoperative factor predictive of MR improvement following AVR (p=0.01). 50% of ischemic and functional MR patients showed improvement in MR following AVR compared to 21% of rheumatic and myxomatous MR patients.
Conclusion: Although some patients with moderate MR were improved following isolated AVR, most patients remained unchanged. Etiology of MR was a significant prognostic factor. Since there was little improvement in the rheumatoid and myxomatous group, replacement or repair should strongly be considered. In the functional and ischemic mitral procedure should be discussed on an individual basis.