Atrial Secondary Tricuspid Regurgitation: Insights Into the EuroTR Registry

Background: Atrial secondary tricuspid regurgitation (A-STR) has been proposed as an important etiologic subentity of secondary tricuspid regurgitation (STR). Patients with A-STR are frequently treated using transcatheter tricuspid valve edge-to-edge repair (T-TEER). Objectives: The aims of this study were to evaluate prevalence and outcomes following T-TEER for severe A-STR and to compare the results to patients with nonatrial STR. Methods: The study included patients from the EuroTR (European Registry of Transcatheter Repair for Tricuspid Regurgitation) registry who underwent T-TEER for STR from 2016 until 2022. A-STR was defined as a ratio of end-systolic right atrial area to right ventricular area ≥1.5 in the presence of preserved right ventricular function (tricuspid annular plane systolic excursion >17 mm). The primary study endpoint was 2-year survival free from heart failure hospitalization. Secondary endpoints were 2-year survival, tricuspid regurgitation (TR) reduction at discharge and 1-year follow-up as well as changes in NYHA functional class. Results: This study included 641 patients (50% women) with a mean age of 79 ± 7 years. The overall prevalence of A-STR was 31% (n = 196). A-STR was associated with a higher prevalence of atrial fibrillation, less frequent comorbidities, better biventricular function, less leaflet tenting, and larger atria. Although TR severity was comparable at baseline, patients with A-STR had more effective procedural TR reduction (TR ≤2+ in 86.9% vs 80.4% of those with nonatrial STR; P = 0.005). Although NYHA functional class improved in both STR subetiologies, the symptomatic burden was lower in patients with A-STR at the latest available follow-up (NYHA functional class ≥III in 46% of patients with nonatrial STR vs 38% in those with A-STR; P = 0.033). Beyond that, A-STR was associated with higher 2-year survival rates free from heart failure hospitalization (66.3% [Q1-Q3: 58.2%-75.5%] vs 47.5% [Q1-Q3: 41.7%-54.7%] in patients with nonatrial STR; P < 0.001). Median survival follow-up was 379 days [Q1-Q3: 155-697 days]. Conclusions: A-STR is a common phenotype of STR and is associated with effective TR reduction and symptomatic reduction after T-TEER.