Impact of right ventricular-pulmonary artery coupling on outcomes in tricuspid regurgitation – insights from the international TRIGSTRY

Background Right ventricular–pulmonary artery (RV-PA) coupling assesses right ventricular function in relation to its adaptation to afterload and has emerged as an important prognostic marker. However, its potential role in identifying patients with tricuspid regurgitation (TR) who may benefit from transcatheter tricuspid valve intervention (TTVI) remains unclear. Objectives To evaluate the potential benefit of TTVI compared to conservative management (medical) according to a non-invasive RV-PA coupling surrogate in patients with severe isolated TR. Methods In TRIGISTRY, a multicenter international registry of patients with severe isolated TR, we identified 908 patients conservatively managed and 1054 patients who underwent a TTVI in whom a noninvasive surrogate of RV-PA coupling, tricuspid annular systolic plane excursion (TAPSE) divided by pulmonary artery systolic pressure (PASP), could be assessed. Patients were categorized according to TAPSE/PASP terciles defined by the medical group with lower tertile representing greater uncoupling: <0.29 mm/mmHg, 0.29-0.43 mm/mmHg, and >0.43 mm/mmHg. We assessed the impact of treatment modality on two-year survival within each TAPSE/PASP tercile after adjustment for comorbidities and the TRI-SCORE. Outcomes for terciles defined by the TTVI group as well as previously reported terciles of TAPSE/PASP, were also explored. Results Survival decreased significantly with lower TAPSE/PASP in both the medical and TTVI groups (both P<0.0001). This was primarily driven by excess mortality in patients within the lowest tercile (Figure 1), whereas no significant difference in mortality was observed between the intermediate and highest terciles in either the medical group (P=0.76) or the TTVI group (P=0.52). Within each TAPSE/PASP tercile, there was no difference in survival between the medical and TTVI groups in low and high terciles (P=0.76 and P=0.79 respectively) whereas a significant survival benefit with TTVI was observed in the intermediate tercile (P=0.0003). Importantly, these findings remained consistent when tercile cutoffs were defined by the TTVI population distribution, (<0.32, 0.32-0.475, and >0.475 mm/mmHg) or based on the reported Euro-TR thresholds (<0.32, 0.32-0.46, and >0.46 mm/mmHg). Conclusions A non-invasive surrogate of RV-PA uncoupling, TAPSE/PASP, was associated with increased mortality irrespective of treatment modality. A potential survival benefit of TTVI was observed in patients within the intermediate RV-PA coupling tercile, but not in the lowest or highest terciles. These findings may help identify patients with severe, isolated TR who are most likely to have a survival benefit from intervention.