Prognostic value of right atrial function in patients with significant tricuspid regurgitation

Aims　Although right ventricular (RV) dysfunction is associated with adverse outcomes in tricuspid regurgitation (TR), the potential role of right atrial (RA) function is unknown. We aimed to investigate the relationship between RA function and clinical outcomes in patients with significant TR.
Methods　This retrospective study included 169 outpatients with moderate or severe TR due to left-sided heart diseases who underwent transthoracic echocardiography between June 2020 and April 2023 (average age, 75 ± 10 years; male, 40%). Patients with atrial fibrillation were excluded from this study due to the inaccuracy of the evaluation using 2D speckle-tracking echocardiography. RA function was compared between patients with and without events, which were defined as all-cause mortality or hospitalization due to heart failure. RA function was calculated as RA global longitudinal strain (RAGLS) with the 2D speckle-tracking echocardiography.
Results　During a median follow-up of 13 months, 19 patients had events (all-cause mortality: 14 cases, hospitalization due to heart failure: 5 cases). RAGLS was lower in patients with events than in those without events (13% ± 10% vs. 18% ± 9%, P = 0.02). When the patients were categorized into two groups [low RAGLS ≤ 16.2% vs. high RAGLS > 16.2%, high RA volume index (RAVI) ≥ 50 mL/m2 vs. low RAVI < 50 mL/m2], Kaplan–Meier curves showed that patients with low RAGLS had higher event rates than those with high RAGLS (log-rank test, P = 0.003). Patients with high RAVI had higher event rates than those with low RAVI (log-rank test, P < 0.001). In the multivariate Cox regression analysis, low RAGLS (≤16.2%) was significantly associated with events in a model that included RV dysfunction (RV fractional area change ≤ 35%) or high RAVI (≥50 mL/m2) (hazard ratio: 4.55, 95% confidence interval: 1.51–13.71, P < 0.01; hazard ratio: 4.57, 95% confidence interval: 1.52–13.79, P < 0.01, respectively).
Conclusions　RAGLS is associated with all-cause mortality and hospitalization due to heart failure in patients with significant TR. Our results suggest that RA function is a sensitive marker for identifying the risk stratification of significant TR.