Three-dimensional echocardiographic assessment of changes in mitral valve geometry after valve repair

Abstract

Background: Application of annuloplasty rings during mitral valve (MV) repair has been shown to significantly change the mitral annular geometry. Until recently, a comprehensive two-dimensional echocardiographic evaluation of annular geometric changes was difficult owing to its nonplanar orientation. In this study, an analysis of the three-dimensional intraoperative transesophageal echocardiographic evaluation of the MV annulus is presented before and immediately after repair.

Methods: We performed three-dimensional geometric analysis on 75 patients undergoing MV repair during coronary artery bypass graft surgery for mitral regurgitation or myxomatous mitral valve disease. Geometric analysis of the MV was performed before and immediately after valve repair with full rings and annuloplasty bands. The acquired three-dimensional volumetric data were analyzed in the operating room. Specific measurements included annular diameter, leaflet lengths, the nonplanarity angle, and the circularity index. Before and after repair data were compared.

Results: Complete echocardiographic assessment of the MV was feasible in 69 of 75 patients (92%) within 2 to 3 minutes of acquisition. Placement of full rings resulted in an increase in the nonplanarity angle or a less saddle shape of the native mitral annulus (137 +/- 14 versus 146 +/- 14; p = 0.002. By contrast, the nonplanarity angle did not change significantly after placement of partial rings.

Conclusions: Mitral annular nonplanarity can be assessed in the operating room. Application of full annuloplasty rings resulted in the mitral annulus becoming more planar. Partial annuloplasty bands did not significantly change the nonplanarity angle. Neither of the two types of rings restored the native annular planarity.

Fig 1

(A) Anterior (ANT), posterior (POST), anterolateral (AL), and posteromedial (PM) landmark identification. (B) Annular markings displayed on the en-face view of the mitral valve. (C) Circumferential annular marking. (D) Identification of the commissures (1), identification of the coaptation line (2), and manually marked coaptation line (3).

Fig 2

Identification of the dimensions of the mitral valve automatically measured during geometric analysis. (AL-PM = anterolateralposteromedial; AP = anteroposterior.)

Fig 3

Geometric measurements during mitral valve analysis. (A) Anteroposterior (AP) diameter is the distance between the anterior and the posterior landmark. (B) Anterolateralposteromedial (AL-AP) diameter is the distance between the anterolateral and posteromedial landmarks. (C) Commissural diameter is the annular diameter at the point of identification of commissures. (D) Anterior annulus length. (E) Posterior annulus length. (F) Non-planarity angle is the angle subtended between the anterior landmark (Ant. LM) and posterior landmark (Post. LM) at the commissural diameter.

Fig 4

Measurement of nonplanarity angle by the mitral valve assessment package. (Ant = anterior; Post = posterior.)

Fig 5

Comparison of the nonplanarity (NP) angle and the annular height commissural width ratio methods of assessment of the saddle shape of the mitral annulus. A: (AH_Max = annular height maximum; AH_Min = annular height minimum; Ant. = anterior annulus; MA plane = mitral annular plane of least square fit; Post. = posterior.) B: Assessment of mitral annular saddle shape by the nonplanarity angle.