The Effect of Systolic Variation of Mitral Regurgitation on Discordance Between Noninvasive Imaging Modalities

Objectives: This study sought to assess the impact of systolic variation of mitral regurgitation (MR) has on discordance between echocardiography and magnetic resonance imaging (MRI). Background: Studies have shown discordance between echocardiography and MRI when assessing the severity of MR. Contributing factors to this discordance may include the systolic variation of MR and the use of the color Doppler jet at a single point in time as the basis of many echocardiographic methods. Methods: This analysis included 117 patients (62 ± 14 years of age; 58% male) with MR who underwent echocardiographic and MRI evaluation. Discordance was defined as the difference between the grades of MR (mild, moderate, or severe) by MRI and echocardiography. For each patient, 2 echocardiographic methods, the continuous wave time index and the color Doppler time index, and 1 MRI method, the systolic variation score (SVS), were measured to quantify systolic variation of MR. Results: There was absolute agreement between echocardiography and MRI in 47 (40%) patients, a 1-grade difference in 54 (46%) patients, and a 2-grade difference in 16 (14%) patients. Only the SVS significantly differed between patients with and without discordance (0.60 ± 0.23 vs. 0.47 ± 0.21; p = 0.003). On receiver-operating characteristic analysis SVS had moderate predictive power of discordance (area under the curve: 0.67; p = 0.003), with an SVS of 53 having a sensitivity of 61% and a specificity of 65% to predict discordance. Conclusions: Discordance between MRI and echocardiographic assessment of MR severity is associated with systolic variation of MR as quantified by MRI using the SVS. Continuous wave Doppler and the presence of color Doppler were not correlated with discordance. This study highlights an advantage of MRI. Namely, it does not rely on a single point in time to determine MR severity. Because systolic variation had only moderate sensitivity and specificity for predicting discordance, other factors are also responsible for the discordance between the 2 techniques.