Right Ventricular-Pulmonary Arterial Coupling and Afterload Reserve in Patients Undergoing Transcatheter Tricuspid Valve Repair

Background: The right ventricular (RV)-pulmonary arterial (PA) coupling ratio relates the efficiency with which RV stroke work is transferred into the PA. Lower ratios indicate an inadequate RV contractile response to increased afterload. Objectives: This study sought to evaluate the prognostic significance of RV-PA coupling in patients with tricuspid regurgitation (TR) who were undergoing transcatheter tricuspid valve repair or replacement (TTVR). Methods: The study investigators calculated RV-PA coupling ratios for patients enrolled in the global TriValve registry by dividing the tricuspid annular plane systolic excursion (TAPSE) by the PA systolic pressure (PASP) from transthoracic echocardiograms performed before the procedure and 30 days after the procedure. The primary endpoint was all-cause mortality at 1-year follow-up. Results: Among 444 patients analyzed, their mean age was 76.9 ± 9.1 years, and 53.8% of the patients were female. The median TAPSE/PASP ratio was 0.406 mm/mm Hg (interquartile range: 0.308-0.567 mm/mm Hg). Sixty-three patients died within 1 year of TTVR, 21 with a TAPSE/PASP ratio >0.406 and 42 with a TAPSE/PASP ratio ≤0.406. In multivariable Cox regression analysis, a TAPSE/PASP ratio >0.406 vs ≤0.406 was associated with a decreased risk of all-cause mortality (HR: 0.57; 95% CI: 0.35-0.93; P = 0.023). In 234 (52.7%) patients with echocardiograms 30 days after TTVR, a decline in RV-PA coupling was independently associated with reduced odds of all-cause mortality (odds ratio [OR]: 0.42; 95% CI: 0.19-0.93; P = 0.032). The magnitude of TR reduction after TTVR (≥1+ vs <1+; OR: 2.53; 95% CI: 1.06-6.03; P = 0.037) was independently associated with a reduction in post-TTVR RV-PA coupling. Conclusions: RV-PA coupling is a powerful, independent predictor of all-cause mortality in patients with TR undergoing TTVR. These data suggest that the TAPSE/PASP ratio can inform patient selection and prognostication following TTVR.