Hemodynamic Characteristics in Significant Symptomatic and Asymptomatic Primary Mitral Valve Regurgitation at Rest and during Exercise

Background - In severe asymptomatic primary mitral valve regurgitation without risk factors, surgery strategy is controversial. We sought to clarify whether being symptomatic corresponds to the hemodynamic burden and reduced exercise capacity. A better understanding of this may contribute to optimize timing of surgery. Methods and Results - Subjects with asymptomatic (New York Heart Association functional class I, n=29) or symptomatic (New York Heart Association functional class II and III, n=28) significant primary mitral valve regurgitation (effective regurgitant orifice, ≥0.30 cm 2; left ventricular ejection fraction, >60%) were included. Right heart catheterization during rest and exercise, echocardiography, magnetic resonance imaging, and peak oxygen consumption test was performed. Symptomatic subjects had significantly higher pulmonary capillary wedge pressure at rest (14±4 versus 11±3 mm Hg; P=0.003) and at maximal exercise (30±6 versus 25±7 mm Hg; P=0.02) and higher mean pulmonary artery pressure (PAP) at rest (22±7 versus 18±4 mm Hg; P=0.005) and maximal exercise (46±8 versus 39±7 mm Hg; P=0.005) than asymptomatic subjects. Among asymptomatic subjects with normal resting value, exercise testing revealed a systolic PAP >60 mm Hg in 34%. Also the reverse response with minimal increase in pulmonary capillary wedge pressure and mean PAP during exercise was seen, especially in asymptomatic subjects. Among symptomatic subjects, we found a significant inverse correlation between resting mean PAP and left ventricular ejection fraction (r=-0.52; P=0.02) and right ventricular ejection fraction (r=-0.67; P<0.01). Peak oxygen consumption was equal and normal in both groups and correlated with left ventricular stroke volume but not with pulmonary capillary wedge pressure. Conclusions - Symptoms in patients with severe mitral valve regurgitation relate to congestion (pulmonary capillary wedge pressure and PAP), but not to peak oxygen consumption, which is determined by forward left ventricular stroke volume. Exercise testing reveals a higher mitral valve regurgitation burden in apparently asymptomatic patients.