Abstract 13305: Comparison of Mitral Regurgitation Severity by Echocardiography and Cardiac Magnetic Resonance Imaging Using Volumetric Quantitative Techniques and Integrative Grading

Abstract

Background: Assessment of the severity of mitral regurgitation (MR) remains a challenge, whether quantitative techniques or an integrative approach of multiple factors are used. The degree of agreement of MR evaluation by 2D Doppler echocardiography (DE) and cardiac magnetic resonance (CMR) is still unclear.

Methods: From 2 institutional databases, 70 subjects with MR were identified that underwent both transthoracic DE and CMR within 30 days (1±8 days). MR severity was assessed quantitatively using volumetric techniques [regurgitant volume (Rvol) and fraction (RF)] by both DE and CMR, as well as semi-quantitatively (4 grades: mild to severe), using an integrative approach. Significant differences between modalities were considered to be a difference of 2 or more semi-quantitative grades, or a difference in RF of ≥ 20%, based on reproducibility analysis of DE. Subjects with and without significant differences in RF were compared using 22 different variables (i.e., eccentric jet, annular calcification, LA vol., etc.). Comparisons between groups were performed using Bland-Altman analysis, Mann-Whitney, and Fisher’s exact tests.

Results: There were 34 women, mean age was 61±16 years; mean LV ejection fraction 47 ± 21%. Etiology of MR was organic in 35 subjects. Of the 70 subjects, 30 had mild, 17 mild to moderate and 23 moderate to severe or severe MR. Exact concordance in grading of MR between DE and CMR was seen in 50% and increased to 91% within 1 grade variation. Overall agreement of MR severity between both modalities is moderate (linear weighted kappa:0.44). Using quantitative criteria (n=60), the correlation of Rvol and RF between DE and CMR were 0.59 and 0.54, respectively. Using Bland-Altman analysis, a tendency for overestimation of Rvol and RF was seen by DE (Mean difference of Rvol: 2.55 ±17 ml, RF: 2.13 ±16 %). There were 10 outliers (difference of ≥ 20% in RF). In these subjects, no trend or significant reason for over or underestimation was seen using 22 DE variables.

Conclusion: Overall, there is moderate agreement in the evaluation of MR severity by DE and CMR. No trends or variables were identified by DE to determine which subjects would benefit from further evaluation with CMR, beyond a technically difficult DE study.