Different right ventricular mechanics in atrial and ventricular secondary tricuspid regurgitation and their prognostic role. A multicentric three-dimensional echocardiography study
Authors: Lakatos B K , Ladanyi Z , Fabian A , Surkova E , Clement A , Muraru D , Tomaselli M , Radu N , Cascella A , Merkely B , Badano L P , Kovacs A 
Published: October 2024

Abstract

Background/Introduction
Secondary tricuspid regurgitation (STR) can develop from markedly different etiologies. Both progressive dilation and dysfunction of the right atrium (atrial phenotype, ASTR), and adverse right ventricular (RV) remodeling (ventricular phenotype, VSTR) may result in STR. RV function is a major determinant of outcome in patients with STR. However, data about how RV function adapts to ASTR and VSTR are scarce, and the prognostic implications of RV mechanics in ASTR and VSTR remain to be clarified.

Purpose
Accordingly, we aimed to investigate the RV mechanical patterns in ASTR and VSTR and to examine their prognostic role using three-dimensional (3D) echocardiography.

Methods
We enrolled 192 patients with STR (60% women) who underwent clinically indicated transthoracic echocardiography in a multicentric prospective observational study. The primary outcome was defined as a composite of heart failure hospitalization or cardiac death. STR etiology was assessed based on the TVARC criteria (ventricular STR n=134, atrial STR n=58). STR severity was categorized using STR effective regurgitant orifice area according to current guidelines. We assessed RV function by measuring the tricuspid annular plane systolic excursion (TAPSE) by M-mode echocardiography and RV ejection fraction (EF) by 3D echocardiography. In addition, we imported the 3D RV meshes into the ReVISION software package (Argus Cognitive, Inc, Lebanon, USA) to quantify the relative contribution of the longitudinal (LEFi), radial (REFi), and anteroposterior motion components (AEFi) to total RV EF.

Results
ASTR and VSTR patients had comparable TAPSE (17±5 mm vs. 18±5 mm, p=0.10), while RV EF was significantly higher in ASTR (54±7% vs. 47±10% p&lt;0.001). Although LEFi (0.37±0.08 vs. 0.38±0.10, p=0.95) and AEFi (0.45±0.08 vs. 0.44±0.11, p=0.53) were comparable between ASTR and VSTR, REFi was significantly lower in VSTR (0.52±0.09 vs. 0.47±0.12, p&lt;0.01). RF EF was comparable among STR severity grades (mild vs. moderate vs. severe: 50±11 vs. 49±9 vs. 50±10%, respectively, p=0.85). Conversely, LEFi was significantly higher in mild and moderate STR vs severe STR (0.39±0.08 vs. 0.39±0.09 vs. 0.35±0.10, respectively, p=0.04). Using multivariable Cox regression based on variables significant in the univariate analysis, REFi was a significant independent predictor of outcome in the entire cohort (hazard ratio: 0.978 [CI, 0.959-0.999], p= 0.037).

Conclusions
Using 3D echocardiographic assessment, ASTR and VSTR patients demonstrated significant differences in the RV mechanical pattern, with a lower contribution of the radial contraction in the case of ventricular STR etiology. While RV EF was comparable between STR severity grades, the relative importance of the longitudinal motion significantly differed. Notably, the relative contribution of radial motion to RV function demonstrated independent prognostic value in patients with STR.RV mechanics in STR severity stages