Impact of Leaflet-to-Annulus Index on Residual Regurgitation Following Transcatheter Edge-to-Edge Repair of the Tricuspid Valve

Background: The mismatch between tricuspid valve (TV) leaflet length and annulus dilation, assessed with the septal-lateral leaflet-to-annulus index (SL-LAI), predicts residual tricuspid regurgitation (TR) following tricuspid transcatheter edge-to-edge-repair (T-TEER). When posterior leaflet grasping is required, the anterior-posterior leaflet-to-annulus index (AP-LAI) may offer additional information. Methods: This single-center retrospective cohort study included all patients referred for T-TEER with severe and symptomatic TR with high surgical risk from April 2021 to March 2024. Patients were categorized into 'optimal result' (= moderate TR) groups. The SL-LAI and AP-LAI were calculated using pre-procedural transesophageal echocardiography (TEE) measurements. Results: Of the 25 patients, 12 had suboptimal post-procedural results, while 13 showed optimal outcomes. The optimal result group showed a higher prevalence of type IIIA-IIIB TV morphology (85% vs. 45%, p < 0.05), a wider SL annulus diameter (42.5 +/- 5 vs. 37 +/- 5 mm, p < 0.05), and a longer posterior leaflet length (28 +/- 4 vs. 22 +/- 5 mm, p < 0.01). The SL-LAI was lower in the optimal group (1 +/- 0.2 vs. 1.2 +/- 0.32, p < 0.05), while the AP-LAI was higher (0.7 +/- 0.1 vs. 0.5 +/- 0.2, p < 0.05). ROC curve analysis showed that the AUC for the AP-LAI was 0.769 (95% CI 0.51-0.93, p < 0.05) and Youden test identified the best cut-off value <0.5 (sensitivity 50% and specificity 100%) for a suboptimal result. The SL-LAI showed a very low AUC in predicting suboptimal results (0.245, 95% CI 0.08-0.47). Comparing the two ROC curves, we showed that AUC difference is significant with the AP-LAI showing the best association with the outcome (p = 0.01). Conclusions: The AP-LAI and SL-LAI can help in predicting post T-TEER results, ameliorating patients' outcomes and avoiding futile procedures.