Comparison of prognostic value among echocardiographic surrogates of right ventricular–pulmonary arterial coupling: A three‐dimensional echocardiographic study

OBJECTIVES: Right ventricular (RV)-pulmonary arterial (PA) coupling is important in various cardiac diseases. Recently, several echocardiographic surrogates for RV-PA coupling have been proposed and reported to be useful in predicting outcomes. However, it remains unclear which surrogate is the most clinically relevant. This study aimed to comprehensively compare the prognostic value of different echocardiographic RV-PA coupling surrogates. METHODS: We retrospectively reviewed 242 patients with various cardiac conditions who underwent comprehensive transthoracic echocardiography with three-dimensional RV data. In addition to conventional parameters including tricuspid annular plane systolic excursion (TAPSE), fractional area change (FAC), and PA systolic pressure (PASP), we analyzed RV free wall and global longitudinal strain (FWLS and GLS). We also obtained RV ejection fraction (RVEF), stroke volume (SV), and end-systolic volume (ESV) using three-dimensional RV analysis. RV-PA coupling surrogates were calculated as TAPSE/PASP, FAC/PASP, FWLS/PASP, GLS/PASP, RVEF/PASP, and SV/ESV. The study endpoint was a composite outcome of all-cause death or cardiovascular hospitalization within 1 year. RESULTS: In multivariable analysis, all the RV-PA coupling surrogates were independent predictors of the outcome. Among the surrogates, the model with TAPSE/PASP showed the lowest prognostic value in model fit and discrimination ability, whereas the model with RVEF/PASP exhibited the highest prognostic value. The partial likelihood ratio test indicated that the model with RVEF/PASP was significantly better than the model with TAPSE/PASP (p < .024). CONCLUSION: All the RV-PA coupling surrogates were independent predictors of the outcome. Notably, RVEF/PASP had the highest prognostic value among the surrogates.