Right Atrial Function Role in Tricuspid Regurgitation-Related Systemic Venous Congestion

: Tricuspid regurgitation (TR) is a frequent valvular pathology and when significant, may cause systemic venous congestion (SC). The right atrium (RA) is an intermediate structure between the tricuspid valve and the venous system and its role in SC is not yet defined. A total of 116 patients with a measurable TR effective regurgitant orifice area (EROA) and regurgitant volume (RVol) were selected from 2020 to 2022. SC was estimated by echocardiography using inferior vena cava diameter and estimated right atrial pressure (eRAP) and by clinical congestive features. TR grade was mild in 23 patients (20%), moderate in 53 patients (46%), and severe in 40 patients (34%). There was a significant decrease in RA function measured by strain with increasing TR severity (p <0.001). There was a marked difference in RA strain between the groups with eRAP >10 and ≤10 mm Hg (25 ± 11% vs 11 ± 7%, p <0.0001). Variables independently associated with inferior vena cava diameter were RA strain (β -0.532, p <0.001), RA volume indexed (β 0.249, p = 0.002), RVol (β 0.229, p = 0.005) and EROA (β 0.185, p = 0.016), and independently associated with eRAP >10 mm Hg were EROA (odds ratio [OR] 1.024, 95% confidence interval [CI] 1.002 to 1.046), RVol (OR 1.039, 95% CI 1.007 to 1.072) and RA strain (OR 0.863, 95% CI 0.794 to 0.940). The addition of RA strain to models containing EROA or RVol significantly improved the power of the model. RA strain was independently associated with the presence of 3 or more congestive features. In conclusion, echocardiographic and clinical signs of SC are frequent in higher degrees of TR, and RA function seems to play a key role in modulating the downstream effect of TR.