Diagnosis of Isolated Cleft Mitral Valve Using Three-Dimensional Echocardiography.

Background: The prevalence of isolated cleft mitral valve (MV; no concomitant congenital heart disease or degenerative MV disease) with significant mitral regurgitation (MR) diagnosed using two-dimensional echocardiography (2DE) has been reported to be very low. Three-dimensional echocardiography (3DE) has enabled a more comprehensive visualization of the MV and detailed understanding of the mechanisms of MR and can potentially reveal isolated cleft MV that is not recognized with 2DE. The aim of this study was to determine, using 3DE, the prevalence, location, and associated MV annular and left ventricular characteristics of isolated cleft MV, in the absence of associated congenital heart disease, in patients with significant MR.

Methods: A total of 1,092 patients with unexplained moderate or greater MR on two-dimensional transthoracic echocardiography who were referred for three-dimensional transesophageal echocardiography between 2005 and 2017 (n = 626) were retrospectively studied. Left ventricular dimensions and function were determined, and quantitative MR assessment and three-dimensional analysis of the MV annulus was performed.

Results: Twenty-one patients (prevalence 3.3%) were diagnosed with isolated cleft MV using three-dimensional transesophageal echocardiography but not 2DE. The majority of these patients (n = 16) were noted to have anterior cleft MVs, with most located in the mid-A1 (n = 10) or mid-A3 (n = 5) scallops. Posterior clefts were less common (n = 5) and occurred at the site of the natural scallop indentations (three between P1 and P2 and two between P2 and P3). Among patients with either anterior or posterior MV cleft, there were no differences in left ventricular ejection fraction or three-dimensional MV geometry (annular distance, height, circumference, and area). There was a trend toward worse MR severity in patients with anterior cleft MV.

Conclusions: In patients with otherwise unexplained significant MR referred for transesophageal echocardiography, 3DE uncovered a considerably higher prevalence of isolated cleft MV than previously reported by 2DE, with the majority located in the anterior MV. Although the annular geometry was similar between patients with anterior and posterior cleft MVs, a trend toward more severe MR in anterior clefts may reflect underlying abnormalities in the embryologic development of the anterior MV leaflet. Evaluation of MV pathology is improved by 3DE, which should be used routinely in the setting significant MR.