Accuracy of Lone Three-dimensional Transthoracic Echocardiography in Tricuspid Valve Function and Geometry Assessment: Implication for Preoperative Evaluation of Transcatheter Tricuspid Valve Therapies

Introduction: Tricuspid regurgitation (TR) is associated with high rate and poor prognosis in patient undertreated. In recent years, transcatheter tricuspid valve interventions (TTVI) appears like a valuable option in high risk surgical candidates in presence of suitable anatomy. Screening phase with transthoracic, thansoesophageal echocardiography, and cardiac computed tomography (CT) are necessary select patients. Purpose: The aim of the study is to compare different imaging modalities as three‑dimensional (3D) transthoracic echocardiography (TTE), transesophageal echocardiography (TOE) and ECG‑gated cardiac CT for the definition of tricuspid valve (TV) function and geometry assessment. Materials and Methods: Twenty‑one (age 79 ± 7 years, female 72%) patients under screening for transcatheter treatment of TR were prospectively enrolled in the study and underwent TTE, TOE, and cardiac CT. All measurements were performed in double blind by three different operators and compared. Results: In the comparison between 2D/3D TTE and 2D/3D TOE, no statistically significant differences were found regarding the evaluation of the valve anatomy, the site of regurgitation, and the underlying mechanism (TTE vs. TOE: 3D septo‑lateral diam 45.8 ± 4,92 vs. 45.87 ± 4,98 mm, P = 0.87; 3D antero‑posterior diam 43.5 ± 4,58 vs. 43.5 ± 4,53 mm, P = 0.59; Circularity index 0,75 ± 0,08 vs. 0,76 ± 0,08, P = 0.98). When comparing 3D TTE and cardiac CT, no differences were recorded in terms of TV area 17.58 ± 3 versus 17.71 ± 4,3 cm2, P = 0.1; perimeter 14.89 ± 1,6 versus 14.29 ± 1 cm, P = 0.5 and diameters. Similarly, in the study of right ventricular dimensions, obtained through 3D volumetric reconstruction, TTE was not statistically different to Cardiac CT. Conclusions: The present series shows how a lone 3D TTE has a good reliability in the definition of TV function, leaflet characteristics, and geometry when compared with second level imaging modalities and may be safely used to select optimal candidates for complex TTVI.