Changes Of Three-dimensional Geometry Of Mitral Annulus In Mitral Regurgitation

Objective Dilatation and deformation c is one of the important mechanism for mitralregurgitation (MR). Geometry of mitral annulus and dynamic changes in cardiac cycle wereevaluated in patients with MR by real-time three-dimensional echocardiography (RT-3DE), toexplore the relationship between structural abnormalities of the mitral annulus and theseverity of MR. Methods Fourty-one patients with MR were divided into two groups: groupof mild MR (18cases) and group of severe MR (23cases) according to the degree of theregurgitation. Twenty-one healthy subjects without significant MR was considered as thecontrol. Dynamic image was collected by Philips IE33ultrasound instrument with RT-3DE.The image of RT-3DE was analyzed offline by TomTec4D images workstation, Germany andmitral annular anterioer-posterior diameter (AP), three-dimensional diameter (CC), annularcircumference (AC), Sphericity index (SI), anterior annular length (AAL), posterior annularlength (PAL), annular area (MAA) and non-planar angel (NPA) were measured. Results Asaddle shape of mitral annulus in three-dimensional geometry was observed in21cases in thecontrol and mild MR, and remains keep its saddle like shape throughout the cardiac cycle inboth control and mild MR groups. Oblate pattern of mitral annulus was existed throughout thecardiac cycle in sever MR group. AP, CC, ALPM, NPA, PAL, AC, MAA were increased in thegroup of mild MR with significant differences statistically (P <0.05) compared with those inthe control. Not only inlarged were AP, CC, ALPM, NPA, MAA, PAL and AC (P <0.05,compared with the control group), but also AAL, AP and ALPM were increased withsignificant difference (P <0.05) in severe MR group in comparison with those of mild MR.Conclusion The relationship between three-dimensional structure of mitral annulus andmechanism of MR was explored by RT-3DE in present study, which indicated that changes inthree-dimensional shape of mitral annular could lead to different degrees of MR in addition topathological lesions of mitral valve. A saddle-like shape of mitral annulus inthree-dimensional geometry was only correlated with mild MR, and flatten pattern of mitralannulus might related to sever MR. Increased PAL was the observed in mild MR. In severeMR, both enlarged PAL and AAL were existed.