Different Causes of Functional Tricuspid Valve Regurgitation Are Linked to Differences in Tricuspid Valve and Right-Sided Heart Geometry and Function: 3D Echocardiography Study

Background and Objectives: The aim of this study was to clarify the tricuspid valve (TV) and right ventricular (RV) geometry and function characteristics using 3D echocardiography-based analysis and to identify echocardiographic predictors for severe tricuspid regurgitation (TR) in different etiologies of functional TR (fTR). Methods and Results: The prospective study included 128 patients (median age 64 years, 57% females): 109 patients with moderate or severe fTR (69-caused by dominant left-sided valvular pathology (LSVP), 40 due to precapillary pulmonary hypertension (PH)), and 19 healthy controls. The 2D and 3D-transthoracic echocardiography analysis included TV, right atrium, RV geometry, and functional parameters. All the RV geometry parameters as well as 3D TV parameters were increased in both fTR groups when compared to controls. Higher RV diameters, length, areas, volumes, and more impaired RV function were in PH group compared to LSVP group. PH was associated with larger leaflet tenting height, volume, and more increased indices of septal-lateral and major axis tricuspid annulus (TA) diameters. LVSP etiology was associated with higher anterior-posterior TA diameter and sphericity index. Univariate and multivariate logistic regression and ROC analyses revealed that different fTR etiologies were associated with various 2D and 3D echocardiographic parameters to predict severe TR: major axis TA diameter and TA perimeter, the leaflet tenting volume had the highest predictive value in PH group, septal-lateral systolic TA diameter-in LSVP group. The 3D TA analysis provided more reliable prediction for severe fTR. Conclusions: TV and RV geometry vary in different etiologies of functional TR. Precapillary PH is related to more severe RV remodeling and dysfunction and changes of TV geometry, when compared to LSVP group. The 3D echocardiography helps to determine echocardiographic predictors of severe TR in different fTR etiologies.