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

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 · kg−1 · 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 · kg−1 · 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.