Characterization of Primary Mitral Regurgitation With Flail Leaflet and/or Wall-Impinging Flow

Background: Echocardiography guidelines note that a flail leaflet is a specific criterion for severe mitral regurgitation (MR) and that regurgitant severity is underestimated in wall-impinging jets (Coandă effect). Both findings are often considered to be pathognomonic of severe MR.

Objectives: In this study, the authors sought to determine the association of flail leaflet and Coandă effect with MR severity quantified by means of cardiac magnetic resonance (CMR).

Methods: The authors enrolled 158 consecutive patients with primary MR according to echocardiography and CMR. The presence of a flail leaflet or Coandă was determined for each patient. CMR regurgitant volume (RV) and regurgitant fraction (RF) were quantified for all patients.

Results: There were 55 patients (35%) with a flail leaflet, 52 (33%) with Coandă, and 22 (14%) with a flail leaflet and Coandă. The mean CMR mitral RV and RF progressively increased in patients without a Coandă or flail, a Coandă, a flail, or a Coandă and a flail (RV: 28 ± 21 mL vs 43 ± 23 mL vs 58 ± 29 mL vs 64 ± 25 mL [P < 0.001]; RF: 25% ± 16% vs 34% ± 14% vs 41% ± 12% vs 45% ± 12% [P < 0.001]). With the use of CMR RV, 35%, 46%, and 59% of patients had severe MR with the presence of a Coandă, flail leaflet, or both, respectively. With the use of CMR RF, 25%, 31%, and 40% of patients had severe MR with the presence of a Coandă, flail leaflet, or both, respectively.

Conclusions: While the presence of a flail leaflet and Coandă effect on echocardiography are associated with higher regurgitant volumes and fractions, they are frequently not associated with severe MR as assessed by means of CMR. (Comparison Study of Echocardiography and Cardiovascular Magnetic Resonance Imaging in the Assessment of Mitral and Aortic Regurgitation; NCT04038879).