Atrial Fibrillation and Clinical Outcomes after Tricuspid Transcatheter Edge-to-Edge Repair: insights form EuroTR Registry

Background: Atrial fibrillation (AF) is a key driver of atrial secondary tricuspid regurgitation (A-STR) and is highly prevalent in patients with significant tricuspid regurgitation (TR). While AF is traditionally associated with adverse outcomes in VHD (valvular heart disease), its prognostic and etiological role in patients undergoing tricuspid transcatheter edge-to-edge repair (T-TEER) remains poorly defined. The aim of the study was to investigate the phenotypic and prognostic implications of AF in patients undergoing T-TEER for severe secondary TR. Methods: In this sub-analysis of the multicenter, retrospective EuroTR Registry (NCT06307262), 2044 patients undergoing isolated T-TEER for symptomatic secondary TR between 2016 and 2024 across 26 European centers were included; patients with concomitant M-TEER or primary/mixed TR were excluded. Patients were compared by AF status and further stratified by TR etiology (A-STR vs. ventricular secondary TR (V-STR), defined by right atrial-to-RV end-systolic area ratio and TAPSE). The RVESA/EROA ratio was derived to express the proportionality between RV remodeling and regurgitant burden. The primary outcome was a non-hierarchical composite of all-cause death and heart failure hospitalization (HFH) at 2 years, assessed with Cox regression and Kaplan-Meier analysis, with multivariable adjustment and center modeled as a cluster effect. Results: AF was present in 1833 patients (92%) and identified a distinct atrial-dominant phenotype: greater biatrial and tricuspid annular enlargement, more severe TR (higher EROA, regurgitant volume, vena contracta), and relatively preserved RV function. Despite greater baseline symptomatic and TR severity, AF patients achieved comparable residual TR and NYHA functional class at follow-up. Over a median follow-up of 526 days, the composite outcome occurred in 26% of patients. AF was associated with a lower risk of the primary outcome (HR 0.73; 95% CI 0.55–0.97; p=0.03), an effect confined to A-STR, whereas V-STR and no-AF patients had comparably worse outcomes. After multivariable adjustment, AF remained independently associated with lower risk (HR 0.68; 95% CI 0.47–0.98; p=0.04). The RVESA/EROA ratio was lowest in A-STR and independently predicted adverse outcomes (adjusted HR 1.23; 95% CI 1.11–1.37; p<0.001). Conclusion: In patients undergoing T-TEER for significant secondary TR, AF identifies a distinct atrial-dominant phenotype with severe TR despite preserved RV function and is associated with more favorable outcomes, particularly in A-STR. The RVESA/EROA ratio captures the relationship between RV remodeling and regurgitant burden and provides independent risk stratification beyond AF status and TR etiology, supporting an integrated assessment of regurgitant burden and ventricular adaptation rather than TR severity alone.