Mechanical Adaptation of the Right Ventricle to Secondary Tricuspid Regurgitation and Its Association With Patient Outcomes

Background: Data regarding right ventricular (RV) mechanical adaptation to secondary tricuspid regurgitation (STR) are scarce. Objectives: The aim of this study was to investigate changes in RV contraction pattern in patients with different degrees of STR severity and etiologies and their association with outcomes. Methods: A total of 205 patients with STR (60% women; mean age, 77 ± 12 years) were enrolled in a single-center prospective observational study. Three-dimensional echocardiography was used to measure RV ejection fraction (RVEF); the absolute contributions of the longitudinal component of RVEF (LEF), the radial component of RVEF (REF), and the anteroposterior component of RVEF (AEF); and their relative contributions by indexing to global RVEF (LEF/RVEF, REF/RVEF, and AEF/RVEF, respectively). Patients were followed for a median of 9 months. The primary outcome was heart failure hospitalization or all-cause death. Results: Patients with different degrees of STR severity did not differ in terms of RVEF (mild vs moderate vs severe: 50 ± 11% vs 49 ± 9% vs 50 ± 10%, respectively, P = .085). However, LEF/RVEF was significantly lower in patients with severe STR (0.39 ± 0.08 vs 0.39 ± 0.09 vs 0.35 ± 0.10, respectively, P = .049). Patients with ventricular STR had lower global RVEF (48 ± 10% vs 53 ± 8%, P = .001), LEF (18 ± 6% vs 20 ± 5%, P = .043), REF (23 ± 9% vs 28 ± 8%, P = .002), and REF/RVEF (0.48 ± 0.012 vs 0.52 ± 0.09, P = .040) than patients with atrial STR. In a multivariable Cox regression model, REF/RVEF was a significant and independent predictor of outcomes in the entire cohort (hazard ratio, 0.980 [95% CI, 0.961-1.000] per 0.01-unit change, P = .047), whereas global RVEF was not. Conclusions: Patients with STR demonstrate significant functional RV remodeling. Patients with severe STR show a significant decrease in RV longitudinal shortening. Apart from STR severity, STR etiology also influences the RV contraction pattern, which was associated with outcomes in our cohort.