Advantages of three-dimensional echocardiography over TAPSE/sPAP for the assessment of right ventricular–arterial coupling in precapillary pulmonary hypertension

Abstract Background: As a well-adopted surrogate of Right ventricular-arterial coupling (RVAC), the tricuspid annular plane systolic excursion/systolic pulmonary artery pressure ratio (TAPSE/sPAP)has limitations, especially when pulmonary artery pressure cannot be accurately estimated by tricuspid regurgitation or when the TAPSE is reduced after cardiac surgery, such as pulmonary endarterectomy (PEA). Therefore, this study aimed to explore whether three-dimensional echocardiography (3DE) coupling parameters could compensate for the deficiency of TAPSE/sPAP in assessing RVAC in precapillary pulmonary hypertension (PH) and chronic thromboembolic pulmonary hypertension (CTEPH) patients. Methods: Fifty-nine patients with precapillary PH were retrospectively recruited. The "gold standard" of RVAC was derived from right heart catheterization (RHC) and cardiac magnetic resonance imaging (CMR). 3DE coupling parameters included right ventricular end-systolic maximum elasticity (3DE Ees), pulmonary artery effective elasticity (3DE Ea) and storke volume/end-systolic volume (3DE SV/ESV) for RVAC. The relationships between echocardiographic RVAC parameters and RHC-CMR coupling standard were analyzed by Pearson’s test and Bland‒Altman test. Multivariate ordinal regression analysis was used to identify echocardiographic parameters associated with prognostic risk stratification. 24 CTEPH patients were enrolled to explore the changes of echocardiographic RVAC parameters before and after PEA. Results: The 3DE coupling parameters showed a strong correlation and good agreement with the RHC-CMR coupling standard. The TAPSE and sPAP were moderately related to the RHC-CMR coupling standard, but their consistency was poor, with a significant bias of 0.44 (95% CI: 0.374, 0.511). TAPSE/sPAP was only associated with pulmonary vascular resistance (PVR) and mean pulmonary artery pressure (mPAP) in CTEPH patients before PEA (r=-0.605, -0.758, P < 0.001), but 3DE SV/ESV remained moderately correlated with PVR and mPAP before and after PEA (r =-0.614, -0.655, P < 0.001). The TAPSE/sPAP was the strongest predictor of prognostic risk after multivariate regression analysis. Conclusion: 3DE-derived coupling parameters can noninvasively evaluate the RVAC of precapillary PH. 3DE SV/ESV is superior to TAPSE/sPAP in evaluating postoperative condition of CTEPH patients. However, TAPSE/sPAP has advantages in predicting the prognosis of patients with precapillary PH.