Severity of mitral and aortic regurgitation as assessed by cardiovascular magnetic resonance: Optimizing correlation with Doppler echocardiography

Background: Cardiovascular magnetic resonance (CMR) is widely recognized as a noninvasive gold standard for quantification of ventricular volumes. In addition, it is an emerging diagnostic modality for clinical evaluation of mitral regurgitation (MR) and aortic regurgitation (AR). CMR facilitates accurate quantitation of regurgitation volumes and regurgitant fraction, but referring physicians are often more comfortable with qualitative measures, and few data exist for correlation of qualitative CMR regurgitation severity with that obtained by more conventional qualitative Doppler echocardiography. Because patients with AR and MR may commonly be assessed by both echocardiography and CMR modalities, consistency between qualitative gradient of regurgitation severity is important for follow-up. Therefore, we sought to define the CMR regurgitant fractions that best correlate with qualitative mild, moderate, and severe regurgitation by color Doppler echocardiography. Methods and Results: Data from 141 consecutive patients (age 53 +/- 15 yr; 43% female) with contemporary (median, 31 days) CMR and echocardiographic data, including 107 regurgitant valves and 70 normal valves, were compared. Thresholds were developed on an initial cohort of patients with 55 regurgitant valves, and subsequently tested on a later cohort of patients with 52 regurgitant valves. Regurgitation fraction (RF) limits that optimized concordance of CMR and echo severity grades were similar for MR and AR and were: mild <= 15%, moderate 16-25%, moderate-severe 26-48%, severe >48%. Conclusions: The current study provides simple qualititative threshold grades for MR and AR severity that allows for standardized reporting of regurgitation severity by CMR and excellent correlation with clinical echocardiography.