Effect of mitral valve repair on exercise tolerance in asymptomatic patients with organic mitral regurgitation

Abstract

Background: The aim of the study was to quantify the changes in cardiopulmonary function after minimally invasive video-assisted mitral valve repair for organic mitral regurgitation (MR) in asymptomatic or minimally symptomatic patients.

Methods: Twenty-six patients (age 54 +/- 11 years) with severe organic MR (regurgitant volume of 94 +/- 37 mL, effective regurgitant orifice [ERO] of 0.73 +/- 0.35 cm2) and mild or no symptoms (New York Heart Association class 1.2 +/- 0.4) underwent exercise echocardiography and cardiopulmonary exercise testing 1 week before and 4 months after uncomplicated video-assisted mitral valve repair.

Results: During exercise, left ventricular ejection fraction increased from 68% +/- 7% to 74% +/- 6% (P < .0001), but ERO did not change significantly. Four months after video-assisted mitral valve repair, a significant improvement was observed in peak oxygen uptake (VO2max from 23 +/- 6 to 25 +/- 7 mL x kg(-1) x min(-1), P < .001), peak oxygen pulse (11 +/- 3 to 12 +/- 4 mL per beat, P < .005) as well as in maximal workload (from 143 +/- 49 to 159 +/- 55 W, P < .0001). When only patients without any symptoms (New York Heart Association class I, n = 20) were considered, these changes were even more pronounced (VO2max from 24 +/- 7 to 27 +/- 7 mL x kg(-1) x min(-1), P < .001). Post-operative changes in VO2max correlated with preoperative exercise-induced contractile reserve (r = 0.72, P < .0001), preoperative ERO (r = 0.49, P < .05), and preoperative ejection fraction at rest (r = 0.42, P < .05).

Conclusion: In patients with severe organic MR but mild or no symptoms, cardiopulmonary performance improves after successful minimally invasive video-assisted mitral valve repair. Improvement is directly related to preoperative left ventricular function and contractile reserve.