Mechanical adaptation of the right ventricle to secondary tricuspid regurgitation, and its association with patients' outcomes.

Abstract

Background: Data regarding the right ventricular (RV) mechanical adaptation to secondary tricuspid regurgitation (STR) is scarce.

Objectives: We investigated the changes in RV contraction pattern in patients with different STR severity and etiology, and their association with outcomes.

Methods: We enrolled 205 patients with STR (60% female, age: 77±12 years), in a single-center prospective observational study. We used three-dimensional echocardiography to measure RV ejection fraction (RVEF), the absolute contribution of the RV longitudinal (LEF), radial (REF), and anteroposterior (AEF) ejection fraction components, and their relative contribution by indexing to global RVEF (LEF/RVEF; REF/RVEF; AEF/RVEF). The patients were followed for a median of 9 months. The primary outcome was defined as heart failure hospitalization or all-cause death.

Results: Patients with different STR severity did not differ in terms of RVEF (mild vs. moderate vs. severe, RVEF: 50±11 vs. 49±9 vs. 50±10%, respectively, p=0.085). However, LEF/RVEF was significantly lower in severe STR (0.39±0.08 vs. 0.39±0.09 vs. 0.35±0.10, respectively, p=0.049). Patients with ventricular STR had lower global RVEF (48±10% vs. 53±8%, p=0.001), LEF (18±6% vs. 20±5 %, p=0.043), REF (23±9% vs. 28±8%, p=0.002), and REF/RVEF (0.48±0.012 vs. 0.52±0.09; p=0.040) 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 [CI, 0.961-1.000] per 0.01 unit change, p=0.047), while global RVEF was not.

Conclusions: Patients with STR demonstrate significant functional RV remodelling. Patients with severe STR show a significant decrease in the RV longitudinal shortening. Apart from STR severity, STR etiology also influences the RV contraction pattern, which was associated with outcomes in our cohort.