Determination of Clinical Outcome in Mitral Regurgitation With Cardiovascular Magnetic Resonance Quantification

Abstract

Background— Surgery for severe mitral regurgitation is indicated if symptoms or left ventricular dilation or 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 mitral regurgitation, and we examined whether this was associated with the future need for surgery. Methods and Results— One hundred nine asymptomatic patients with echocardiographic moderate or severe mitral regurgitation had baseline CMR scans and were followed up 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 ≤55 mL survived to 5 years without surgery compared with only 21% with regurgitant volume >55 mL ( P <0.0001). A similar separation was observed for regurgitant fraction ≤40% and >40%. CMR-derived end-diastolic volume index showed a weaker association with outcome (proportions surviving without surgery at 5 years, 90% for left ventricular end-diastolic volume index <100 mL/m 2 versus 48% for ≥100 mL/m 2 ) and added little to the discriminatory power of regurgitant fraction/volume alone. Conclusions— CMR quantification of mitral regurgitation was associated with the development of symptoms or other indications for surgery and showed better discriminatory ability than the reference-standard CMR-derived ventricular volumes. CMR may be able to identify appropriate patients for early surgery, with the potential to change clinical practice, although the clinical benefits of early surgery require confirmation in a clinical trial.

Cardiac Magnetic Resonance Imaging Versus Transthoracic Echocardiography for Prediction of Outcomes in Chronic Aortic or Mitral Regurgitation

“…There was a trend toward superior performance of TTE-derived by CMR-derived regurgitant volume and fraction and need for mitral valve surgery; however, they also reported that TTE measurements did not predict the need for valve surgery. 22 Our results are discordant in that we found a trend toward better prediction of outcomes with TTE as compared to CMR. The reason for this discordance is unclear but notable differences in study design were that echocardiography used in the current study was done as a part of the research protocol as opposed to This study has several limitations.…”

Role of Cardiac Magnetic Resonance Imaging in Valvular Heart Disease: Diagnosis, Assessment, and Management

“…Gelfand et al previously found that CMR-RF thresholds for MR with maximal agreement with echo were mild ≤ 15%, moderate 16–24%, moderate-severe 25–42%, severe > 42% [47]. More recently, Myerson et al showed that a Rvol threshold of > 55 mL and RF > 40% accurately identified patients who progressed to symptomatic MR or other indications for mitral valve surgery [51]. These studies suggest that CMR-specific thresholds need to be better defined.…”

Recommendation of Early Surgery in Primary Mitral Regurgitation: Pros and Cons

“…Cardiovascular magnetic resonance (CMR) is able to quantify MR with high accuracy and reproducibility using a combination of left ventricle (LV) volumetric measurements and aortic flow quantification. Myerson et al 2 reported that quantifying MR with CMR showed a strong association with the future need for surgery over the subsequent 5 years, demonstrating the potential value of this approach. Previous studies also suggest only moderate agreement between CMR and echocardiography 3,4 and limited reproducibility for quantitative echocardiographic grading.…”

“…These CMR parameters might prove useful for identifying suitable patients for early mitral valve repair replacement. 2 …”

“…Myerson et al 2 and Enriquez-Sarano et al 3 articles show how extremely important is to demonstrate the existence of patient subgroups which could have benefited from an early mitral valvular surgery. Nevertheless, the parameters evaluated in this article need validation in future studies due to the work's pattern under discussion (observational study, non-blinded, surgical recommendation based on the patient's doctor opinion).…”