Tricuspid leaflet identification on 2D multiplane transoesophageal echocardiography: lessons from 3D

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background —Tricuspid valve (TV) leaflet identification by two-dimensional (2D) transoesophageal echocardiography (TOE) is complex due to the high variability of the combinations of leaflets visualized in each view. 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 (MPR) of 3D datasets, we aimed at describing anatomical landmarks able to identify TV leaflets easily and effectively during multiplane 2D TOE. Methods —TOE data from 83 patients was retrospectively collected. Multiplane 2D images of the TV and matching 3D datasets recorded from the same probe position were compared to precisely identify the leaflets visualized on each 2D image. To increase the number of multiplane (orthogonal) 2D images available for analysis, a novel approach was used: 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). After data analysis, a comprehensive "two-step" reference table was generated. To evaluate the clinical utility of the findings, eleven (11) echocardiographers were shown a random set of 5 images, and asked to label the leaflets visualized, prior and after a brief explanation on how to use the proposed reference table. Results —After removal of redundant information, a total of 231 sets of leaflets combinations was obtained. The number of leaflets visualized (one or two) and the presence (or absence) of the interventricular septum allowed consistent identification of the TV leaflets depicted in the 2D home view, as confirmed by correlation with the matching 3D MPR dataset. A similar analysis was carried out on the orthogonal 2D images resulting from three different multiplane cursor positions (distal, mid, and proximal to the aortic valve/interventricular septum). By combining information from the two views, leaflet identification was accurate, intuitive and easy, as summarized in the reference table (Fig. 2). The accuracy in exact leaflet recognition 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). Conclusion — Simple anatomical landmarks allow precise TV leaflet identification during multiplane 2D TOE. A simplified two-step approach significantly improves accuracy in leaflet recognition among both beginners and advanced echocardiographers.