Right ventricular reverse remodelling and pulmonary pressure changes post-TTVR for tricuspid regurgitation

Introduction Transcatheter Tricuspid Valve Replacement (TTVR) is a minimally invasive treatment for severe tricuspid regurgitation (TR). While significant improvement in quality-of-life post-intervention has been demonstrated, the post-procedural changes in right ventricular (RV) morphology and physiology are poorly understood. Purpose To determine RV morphological changes post-intervention and their association with changes in cardiac function and pulmonary pressures. Secondary aim was to explore associations between changes in the latter 2. Methods This is a single-centre observational analysis of patients who underwent TTVR for symptomatic ≥ severe TR at a specialist referral centre from June 2024 to September 2025. Routine 2-dimensional transthoracic echocardiography (TTE) at timepoints: pre-procedure, <48hrs, 1-3 and 5-9 months was used. Associations in TTE-measured RV size, function, PASP and cardiac output (CO) were analysed using univariate Pearson’s or Kendall’s Tau correlation coefficient as appropriate, and temporal changes in parameters with paired t-tests. Results 19 patients underwent TTVR: 12 (63%) female, mean age 82 years (IQR 79-84). Pre-intervention, 26% had severe, 26% massive and 47% torrential TR. Post-intervention all patients had ≤mild-moderate TR, with 100% procedural success and no conversion to surgery. Significant RV reverse remodelling was seen by 5-9 months (Fig. 1). Decrease in RV base diameter trended towards significance at 1-3 months (p=0.114). RV mid diameter significantly declined from baseline by 5-9 months (p=0.002). Similarly, a significant decline in RV end diastolic area (EDA) at 1–3 months was seen (p=0.036). RV end systolic area (ESA) increased significantly at 1-3 months (p=0.034), later decreasing; however, baseline to 5-9 months slightly increased without significance (p=0.143). RV length shows similar trends. A significant decline in RV function was seen by 5-9 months: TAPSE (p<0.001), RV S’ (p=0.005), FAC (p<0.001) and global RV function (p=0.005). Forward CO significantly increased from baseline (p=0.023). PASP saw a significant decline (p=0.05). Baseline PASP and RV-PA coupling (TAPSE/PASP) correlated with early RV reverse remodelling at 1-3 months (Tables 1 and 2), but not at 5-9 months. Curiously, there was no clear relationship between measures of RV function and output, and between RV output and RV-PA coupling. Conclusion This study shows significant changes in RV structure and function, forward CO and PASP post-TTVR. The changes in RV morphology, especially RV ESA and length, along with the corresponding changes in RV function, forward output and PASP, suggest two phases of reverse remodelling: initial unloading of the RV overload, followed by a later phase – perhaps myocardial muscle fibre shortening. A continuous decline in metrics of RV function was observed, while forward CO increased. Baseline PASP correlated with the extent of early reverse remodelling.