Aortic Regurgitation Quantification Using Cardiovascular Magnetic Resonance

Abstract

Background-Current indications for surgery in patients with significant aortic regurgitation (AR) focus on symptoms and left ventricular dilation/dysfunction. However, prognosis is already reduced by this stage, and earlier identification of patients for surgery could be beneficial. Quantifying the regurgitation may help, but there are limited data on its link with outcome. Cardiovascular magnetic resonance (CMR) can accurately quantify AR, and we examined whether this was associated with the future need for surgery. Methods and Results-One hundred thirteen patients with echocardiographic moderate or severe AR were monitored for up to 9 years (mean 2.6Ϯ2.1 years) following a CMR scan, and the progression to symptoms or other indications for surgery was monitored. AR quantification identified outcome with high accuracy: 85% of the 39 subjects with regurgitant fraction Ͼ33% progressed to surgery (mostly within 3 years) in comparison with 8% of 74 subjects with regurgitant fraction Յ33% (PϽ0.0001); the area under the curve on receiver operating characteristic analysis was 0.93 (PϽ0.0001). This ability remained strong on time-dependent Kaplan-Meier survival curves. CMR-derived left ventricular end-diastolic volume Ͼ246 mL had good, although lower, discriminatory ability (area under the curve 0.88), but the combination of this measure with regurgitant fraction provided the best discriminatory power. Conclusions-High degrees of CMR-quantified AR were associated with the development of symptoms or other indications for surgery. Quantifying AR showed slightly better discriminatory ability than "gold standard" CMR ventricular volume assessment. This could provide a new paradigm for the timing of surgical intervention but requires confirmation in a clinical trial.

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

“…In a recent study, Myerson, et al found that LV volumes and regurgitant volume were predictive of future events in 113 subjects with chronic AR, with a CMR-derived RF >33% having 85% sensitivity and 92% specificity for identifying subjects who progressed to valve surgery. 11 Similarly, in the current study subjects with a CMR-derived regurgitant volume ≤50 mL/beat had a very low rate of valve surgery and a CMR-derived aortic RF of ≥37% had a sensitivity of 100% and specificity of 75% for the…”

“…However, there is relatively little literature to correlate CMR measures of valve dysfunction with clinical outcomes. [11][12][13][14][15][16][17] We have previously shown that CMR is more reproducible than TTE in quantification of AR and MR severity with less inter-observer and intra-observer variability. 18 The purpose of the current study was to determine how measurements made by TTE and CMR correlate with clinical outcomes in subjects with AR or MR. We hypothesized that measurements obtained by CMR may be superior to TTE for predicting the development of the primary composite endpoint of undergoing valve surgery for the primary indication of valve regurgitation or hospitalization for valvular HF in subjects with chronic AR and chronic, primary MR who did not have indications for valve surgery at baseline.…”

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

“…The separation of the Kaplan-Meier event curves was slightly less pronounced than in our previous work in aortic regurgitation, 14 which may be attributable to a number of factors. MR is partly dependent on nonvalvar factors (eg, fluid balance, filling pressures, LV function), and the quantity of MR may vary more widely over a period of time than aortic regurgitation.…”

“…12 Given that LV volumes and function are also important for MR assessment and that CMR is considered the referencestandard method for measuring them, 13 CMR would appear to be an optimal technique for the assessment of MR. We previously used this technique in patients with aortic regurgitation and demonstrated a strong association of the quantification of regurgitation with outcome. 14 We therefore sought to examine whether a similar approach using CMR quantification of MR and LV indexes might be able to predict which asymptomatic patients with significant (moderate or severe) MR were likely to progress to symptoms or other established indications for surgery. We also aimed to compare the CMR quantification of MR and LV volume/function indexes for their relative predictive ability.…”

Prospective Comparison of Valve Regurgitation Quantitation by Cardiac Magnetic Resonance Imaging and Transthoracic Echocardiography

“…8,[16][17][18] In addition, echocardiographic PISA calculation of ROA and CMR measurement of AR regurgitant fraction both have established prognostic value. 19,20 Our data show that measurement of LV volumes and ejection fraction by CMR is more reproducible than by 2-dimensional TTE. Previous studies have shown that CMR is more accurate than TTE for LV volume determination, and as found in previous studies, we similarly found that TTE consistently underestimates LV volumes and overestimates ejection fraction compared with CMR.…”