Echocardiographic Features and Clinical Outcomes of Flail Mitral Leaflet without Severe Mitral Regurgitation

Flail mitral leaflet is a common complication of degenerative mitral regurgitation (MR) and is generally equated with severe MR. However, a flail mitral leaflet is not always associated with severe MR. The hemodynamic and clinical significance of a flail leaflet in the absence of severe MR has not been characterized. The authors identified cases of flail mitral leaflet associated with only mild or moderate MR and evaluated their echocardiographic features and clinical outcomes.

The echocardiography database at Cedars-Sinai Medical Center was queried for reports of flail mitral valve leaflet. Cases of possible flail and ≤3+ MR were identified and adjudicated for the presence of definite flail and ≤2+ MR. These patients were retrospectively evaluated by chart review to determine clinical outcomes.

Seven hundred six cases of possible flail were identified, of which 143 were identified as having ≤3+ MR. Of these, 14 cases were identified with definitive echocardiographic evidence of a flail mitral leaflet and ≤2+ MR. Over a median of 361 days of follow-up, MR progressed in severity in only one patient, in association with endocarditis and death. All other patients were free of progression of MR, heart failure, or mortality during follow-up.

A flail mitral leaflet is not synonymous with severe MR and can be associated with only mild or moderate MR. Furthermore, patients with flail mitral leaflet and only mild to moderate MR were clinically stable. Thus, an integrated, multiparametric approach should be used to assess MR severity, even in the presence of a flail mitral leaflet.