124: Echocardiographic determinants of maximal exercise capacity in asymptomatic patients with primary mitral regurgitation

Background Despite a symptom-based management recommended by current guidelines in patients with primary mitral regurgitation (MR), the assessment of maximal exercise capacity (MEC) is rarely performed. MEC is relatively unexplored in these patients and its exercise determinants remain unknown. Method and results We prospectively studied 63 asymptomatic patients (60±13 years, 52% of male) with at least moderate MR and with preserved left ventricular (LV) systolic function in whom comprehensive resting and exercise echocardiography and cardiopulmonary exercise test were performed. MEC was assessed using peak exercise VO2 and widely varied over patients (mean: 23.6±7, median: 22.7, range: 10.2–42.4 ml/kg/min). According to the median of peak VO2, patients with reduced MEC were significantly older (p=0.0052) and were more frequently women (p=0.02). There was no other significant difference between the 2 groups (reduced vs. preserved MEC) regarding demographic and clinical data and medication. During exercise, Peak VO2 was significantly correlated with exercise LV stroke volume (r=−0.33, p=0.02) and there was a trend for significant correlation with exercise RegV and effective regurgitant orifice area (r=−0.32, p=0.05 and r=−0.3, p=0.07, respectively). In addition, the best correlations with peak VO2 were found with exercise SPAP (r=−0.52, p 2 =0.67), after adjustment for exercise LV stroke volume and resting E/Ea, age (β=−0.17± 0.07, p=0.02), sex (β=−3.1±0.8, p=0.0006), exercise LA volume (β=−0.12± 0.03, p=0.02) and exercise SPAP (β=−0.15±0.06, p=0.0003) were identified as independent predictors of peak exercise VO2. Conclusion In asymptomatic patients with primary MR and preserved LV systolic function, MEC may vary considerably. The main independent determinants of MEC are related to MR consequences on LA and SPAP, in particular during exercise.