Tricuspid leaflet identification on 2D multiplane transesophageal echocardiography: derivation and validation of a simple two-step approach

Tricuspid valve (TV) leaflet identification by two-dimensional (2D) transesophageal echocardiography (TOE) is complex due to the considerable variability in the visualized leaflets. While three-dimensional (3D) imaging can easily overcome this problem by acquiring the whole valve anatomy, the overall image quality is often suboptimal and the technique somewhat unsuitable for real-time monitoring during interventional procedures like TriClip implantation. Using information derived from both 2D and multiplanar reconstruction of 3D datasets, we elaborated a step-wise approach to identify TV leaflets during multiplane 2D TOE and tested it on a validation cohort.

TOE data from 83 patients was retrospectively collected. The 3D data of each patient was appropriately sliced to simulate and accurately match what would be seen by "sweeping" the cursor across the TV during real-time multiplane imaging (Fig. 1). Following data analysis, a "two-step" reference table was created and subsequently evaluated for accuracy on a validation cohort of 41 patients from a distinct hospital and country. To evaluate the usability of the approach, 11 echocardiographers were presented with a random selection of 5 multiplane images. They were then instructed to identify the visualized leaflets initially without using the reference table, and subsequently with its assistance.

After removal of redundant information, 231 unique multiplane sets were obtained. Combining anatomical features (number of leaflets visualized and presence of the interventricular septum) from the 2D views allowed easy and consistent identification of TV leaflets (Fig. 2), as confirmed by correlation with the 3D dataset. The same "two-step" approach was subsequently tested on an independent validation cohort of 41 patients (96 unique multiplane sets). Accurate leaflet identification was possible in 35 patients (85%), while in 6 cases (15%) the image sector was too narrow to confidently assess the presence of the interventricular septum. The accuracy in exact leaflet recognition without the aid of the reference table was rather modest (mean score of 1 out of 5) among echocardiographers with different experience in TV TOE, but significantly increased (mean score of 3.2 out of 5) with the adoption of the proposed approach, accounting for a 44% improvement in accuracy (p< 0.001).

Simple anatomical features allow precise TV leaflet identification during multiplane 2D TOE. A streamlined "two-step" approach, validated on an independent cohort of patients, significantly improves accuracy in leaflet recognition among both beginner and advanced echocardiographers.