Stop guessing, start xPlane-ing tricuspid leaflets on transesophageal echocardiography

Abstract Background 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 T-TEER. Using information derived from both 2D and multiplanar reconstruction of 3D datasets, we described the prevalence of each leaflet combination and elaborated a step-wise approach to identify TV leaflets during multiplane 2D TOE. The proposed method was then tested on a validation cohort. Methods 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. For each patient, two sets of orthogonal 2D images were generated: one set with the multiplane cursor positioned on the proximal leaflet and the other set with the multiplane cursor selecting the distal leaflet (Fig. 1). Following data analysis, a reference table was created and subsequently tested on a validation cohort of 95 patients from a distinct hospital and country. Accuracy and reasons for error were noted. Results Combining anatomical features (number of leaflets visualized, presence/absence of the coronary sinus and the interventricular septum) from the simulated 2D views allowed easy and consistent identification of TV leaflets (Fig. 2), confirmed by using the 3D dataset as reference. The same "two-step" (i.e. positioning the multiplane cursor on the proximal and then on the distal leaflet) approach was subsequently tested on an independent validation cohort of 95 patients. Accurate leaflet identification was possible in 90 patients (95%), while in 5 cases (5%) the predicted leaflets were incorrect: in 2 cases the image sector was too narrow and did not show the interventricular septum (thus impeding the recognition of the septal leaflet), in 2 cases the two non-septal leaflet were mistaken for a single leaflet, and 1 case a single leaflet was mistaken for two non-septal leaflet. Conclusion We report the prevalence of TV leaflet combinations seen on 2D multiplane TOE. Simple anatomical features allow precise TV leaflet identification and a streamlined "two-step" approach, validated on an independent cohort of patients, shows high accuracy in leaflet recognition.Fig. 1 Fig. 2