Right atrial-to-right ventricular area ratio: prognostic value in patients with secondary tricuspid regurgitation

Background Severe secondary tricuspid regurgitation (STR) among patients with heart failure is associated with excess mortality. Quantification associated risk assessment, remains challenging- specifically with the contextual anatomic variability. Recent observations identified different morphological substrates of STR based on the predominance of either ventricular or atrial remodeling. The extent of predominant remodeling can be expressed as ratio between right atrial/right ventricular area (RA/RV). Objective The aim was to investigate prognostic implications of the RA/RV ratio in patients with STR and its impact across the heart failure spectrum. Methods This observational study included 11,955 patients from 2010-2020 with STR, of which 1,219 had severe STR. Based on the RA/RV ratio patients were allocated to those with predominant atrial remodeling (RA/RV ratio ≥1.17) versus those with predominant ventricular remodeling (RA/RV ratio <1.17). The primary endpoint was all-cause mortality. Results Quantified STR showed similar STR severity in both groups (EROA: 0.45 vs 0.46; p>0.9, vena contracta width: 13.7 vs 13.5; p=0.3). There was no significant difference in neurohumoral activation (NT-proBNP 3,452 vs 3,567 p=0.6). At eight years, patients with predominant atrial remodeling had the highest fatal event rate compared to predominant ventricular remodeling and at risk for STR (47% vs 39% vs 31% respectively). Spline analysis revealed a linear relationship between RA/RV ratio and mortality. Both STR remodeling types had impaired survival compared to patients at risk of severe STR (predominant atrial remodeling: hazard ratio [HR] 2.00, 95% confidence interval [CI] 1.78-2.26, p<0.001; predominant ventricular remodeling: HR 1.58, 95%CI 1.39-1.81 p<0.001), with more prominent impact of those with RA/RV ratio ≥1.17 (p<0.001). The impact of severe STR remained in both subgroups after adjustment for bootstrap and clinical confounder models. Conclusion RA/RV ratio is an easily obtainable metric, indicating predominant remodeling patterns and associates with morphological features of valve apparatus distortion secondary to differential remodeling. Despite comparable quantified STR and neurohumoral activation, there is a robust association between the RA/RV ratio and mortality. Whether patient selection by RA/RV ratio might help identify those that might benefit beyond symptomatic improvement needs to be demonstrated by future research.Kaplan-Meier long-term survival analysis