Mitral valve repair results in better right ventricular remodelling than valve replacement for degenerative mitral regurgitation: a three-dimensional echocardiographic study.

INTRODUCTION Right ventricular (RV) remodelling may be an important determinant of clinical outcome in patients undergoing mitral valve surgery for mitral regurgitation. In the present study we hypothesised that, compared to valve replacement, mitral valve repair for degenerative mitral regurgitation may result in better RV remodelling, as assessed by real-time, three-dimensional echocardiography (RT3DE). METHODS Forty unselected patients with degenerative mitral valve regurgitation were recruited prospectively. Two-dimensional (2DE) and RT3DE studies were performed prior to surgery and 6 months postoperatively. RV volumes, stroke volume, ejection fraction and mass, as well as RV pressures were calculated. Regression analysis was used to demonstrate the effect of surgical mitral repair and replacement on reverse RV remodelling. RESULTS Twenty-one patients underwent mitral valve repair and 19 valve replacement. Mean age was 59.5 ± 15.4 years. Five patients who underwent repair (23.8%) developed recurrent MR within 6 months postoperatively. RV systolic pressure was reduced from 39.3 ± 11.9 mmHg, to 25.4 ± 8.3 mmHg after surgery (p=0.027). Compared to preoperative volumes, 6 months after surgery there was a significant reduction in RV diastolic volume and stroke volume (from 106.4 ± 16.3 ml to 80.4 ± 12.1 ml and from 69.2 ± 15.4 ml to 52.2 ± 14.1 ml, respectively, p<0.001), and an increase in RV ejection fraction (from 54.5 ± 9.2% to 67.3 ± 8.5%, p<0.001). Over a 6-month follow-up period there were no deaths. Overall, the functional class was significantly improved in 39/40 patients (97.5%) but there was no difference between the repair and replacement groups. Using a multivariate regression analysis model including all parameters composing RV remodelling postoperatively, mitral valve repair was the strongest predictor of reverse RV remodelling (reduction of RV end-diastolic volume, p<0.01; reduction of RV mass, p<0.01; reduction of tricuspid regurgitant velocity, p=0.019). CONCLUSIONS Mitral valve repair leads to more favourable reverse RV remodelling, assessed by RT3DE, compared to valve replacement. This may have important clinical implications.