Abstract 12682: The Effect of Systolic Variation of Mitral Regurgitant Severity on Discordance Between Non-Invasive Imaging Modalities

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Introduction: Studies have shown a significant degree of discordance between echocardiography (Echo) and MRI in the quantification of mitral regurgitation (MR). A contributing factor to this discordance may be the systolic variation of MR severity. The ASE recommended quantitative parameters such as PISA and vena contracta rely on a single measurement during systole. These measurements can overestimate MR when MR severity varies during systole. We have previously developed a method to quantify the variation of MR during systole. Hypothesis: Greater systolic variation of MR severity is associated with discordance between MRI and Echo. Methods: This study included 94 pts (60 ± 14 yrs, male 60%) with MR. Echo was read per the ASE integrated method as mild, moderate or severe. Each MRI was read as mild, moderate, or severe based on calculated MR volume. Discordance was defined as the difference between the grades of MR (mild, moderate, or severe) by MRI and Echo. On MRI, systole was divided into thirds and the regurgitant rate was calculated for each third of systole as the difference between LV stroke volume and aortic outflow per unit time. The degree of systolic variation of MR severity was quantified by dividing the lowest regurgitant rate by the peak regurgitant rate, with higher numbers representing lower variation of MR severity during systole. Results: There was absolute agreement between echo and MRI in 38 pts, 1 grade difference in 41 pts, and a 2 grade difference in 15 pts. There was a trend of greater systolic variation of MR rate in pts with greater discordance between MRI and echo (figure). Pts with no discordance between echo and MRI had a significantly lower systolic variation of MR severity than those with 1 or 2 grades difference. Conclusions: Discordance between Echo and MRI in assessing MR severity was associated with greater systolic variation in MR severity. Thus, caution should be taken not to overestimate MR severity in patients with systolic variation of their MR.

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