Determination of clinical outcome in mitral regurgitation with cardiovascular magnetic resonance quantitation

Background: Surgery for severe mitral regurgitation (MR) is indicated if symptoms or LV dilation/ dysfunction occur. However, prognosis is already reduced by this stage and earlier surgery on asymptomatic patients has been advocated if valve repair is likely, but identifying suitable patients for early surgery is difficult. Quantifying the regurgitation may help, but evidence for its link with outcome is limited. Cardiovascular magnetic resonance (CMR) can accurately quantify MR, and we examined whether this was associated with the future need for surgery. Methods and results: 109 asymptomatic patients with echocardiographic moderate or severe MR had baseline CMR scans and were followed for up to 8 years (mean 2.5±1.9 years). CMR quantification accurately identified patients who progressed to symptoms or other indications for surgery: 91% of subjects with regurgitant volume ≤55ml survived to 5 years without surgery compared to only 21% with regurgitant volume >55ml (p<0.0001); similar separation was observed for regurgitant fraction below and above 40%. CMR-derived end-diastolic volume index showed a weaker association with outcome (proportions surviving without surgery at 5 years: 90% for LVEDVi