Is the Anterior Intertrigonal Distance Increased in Patients With Mitral Regurgitation Due to Leaflet Prolapse?

Background: Severe mitral regurgitation (MR) leads to progressive enlargement of left ventricular dimensions and, consequently, the mitral valve (MV) annulus. Data from animal and cadaver studies suggest that the mitral annulus may dilate asymmetrically in certain conditions, which may influence the choice of valve repair technique. Although it is generally accepted that the posterior mitral annulus dilates in patients with severe MR due to leaflet prolapse, the stability of the anterior intertrigonal distance has not yet been demonstrated in humans. Methods: We obtained real-time, three-dimensional (3D) transesophageal echocardiographic images of the MV in 44 patients: 29 patients scheduled to undergo MV repair for severe MR due to leaflet prolapse (MV disease group) and 15 normal outpatients undergoing evaluation for various reasons (control group). Mitral valve repair was performed by median sternotomy or minimally invasively using thoracoscopic or robotic assistance. All patients underwent implantation of a standard-length flexible 63-mm posterior annuloplasty band at the time of mitral repair and we obtained postoperative 3D images for 11 patients after separation from bypass. Mitral annular dimensions were measured throughout the cardiac cycle using reconstructive analysis software (QLAB MVQ Version 6.0; Phillips, Bothell, WA). Results: The mean patient age was 60 years; 30 were men. The mean ejection fraction was 0.61 and was similar between the two groups (p = 0.16). In patients with MR due to leaflet prolapse, posterior annular length and total annular circumference were significantly larger than in control patients (p < 0.001). In contrast, there was no detectable difference in the anterior intertrigonal distance between patients with MR and normal controls. After mitral valve leaflet repair and posterior annuloplasty there was a significant decrease in both the total annular circumference and posterior annular length (p < 0.0001) while cyclic annular contraction was preserved. Conclusions: Although the posterior mitral annulus is enlarged in patients with significant MR due to degenerative leaflet prolapse, there is no evidence that the intertrigonal distance is abnormal in these patients. Our data support the conclusion that posterior annular reduction with a flexible device at the time of mitral valve repair is important, and that altering the anterior intertrigonal portion of the mitral annulus is unnecessary.