Tricuspid annular geometry: a three-dimensional transesophageal echocardiographic study

Abstract

Objective: To demonstrate the clinical feasibility of accurately measuring tricuspid annular area by 3-dimensional (3D) transesophageal echocardiography (TEE) and to assess the geometric differences based on the presence of tricuspid regurgitation (TR). Also, the shape of the tricuspid annulus was compared with previous descriptions in the literature.

Design: Prospective.

Setting: Tertiary care university hospital.

Interventions: Three-dimensional TEE.

Participants: Patients undergoing cardiac surgery.

Measurements and main results: Volumetric data sets from 20 patients were acquired by 3D TEE and prospectively analyzed. Comparisons in annular geometry were made between groups based on the presence of TR. The QLab (Philips Medical Systems, Andover, MA) software package was used to calculate tricuspid annular area by both linear elliptical dimensions and planimetry. Further analyses were performed in the 4D Cardio-View (TomTec Corporation GmBH, Munich, Germany) and MATLAB (Natick, MA) software environments to accurately assess annular shape. It was found that patients with greater TR had an eccentrically dilated annulus with a larger annular area. Also, the area as measured by the linear ellipse method was overestimated as compared to the planimetry method. Furthermore, the irregular saddle-shaped geometry of the tricuspid annulus was confirmed through the mathematic model developed by the authors.

Conclusions: Three-dimensional TEE can be used to measure the tricuspid annular area in a clinically feasible fashion, with an eccentric dilation seen in patients with TR. The tricuspid annulus shape is complex, with annular high and low points, and annular area calculation based on linear measurements significantly overestimates 3D planimetered area.

Keywords: 3-dimensional transesophageal echocardiography; cardiac surgery; right ventricle; tricuspid annuloplasty; tricuspid regurgitation; tricuspidvalve.

Fig 1

Tricuspid annulus recreated with 32 landmark points in the TomTec 4D Cardio-View environment. All points are represented in the 3D representation of the right ventricle at the bottom right corner.

Fig 2

An example of a mathematic reconstruction of the tricuspid annulus in MATLAB following importing of coordinates from TomTec 4D Cardio-View. The upper frame shows a plot of all the coordinates in the 3 dimensions of X, Y, and Z. The least-square plane fit line represents the neutral plane of the annulus, which is used as the baseline in the lower panel. Here, the annular high and low points are indicated as +Z and −Z to reconstruct the 3D annulus.

Fig 3

Tricuspid annular data imported into the QLab MPR environment to accurately measure planimetered annular area in the bottom left corner. Through 3D manipulation of the coronal and sagittal planes, an ideal axial plane for measurement by planimetry can be achieved.

Fig 4

Scatterplot of tricuspid annular area as measured by the ellipse formula in MATLAB versus area as measured by direct planimetry by 3D MPR in QLab.

Fig 5

The Bland-Altman analysis to compare the agreement of the tricuspid annular area as measured by the ellipse formula in MATLAB versus area as measured by direct planimetry by 3D MPR in QLab. (Color version of figure is available online.)