Assessment of Right Ventricular‐Pulmonary Arterial Coupling in Heart Failure With Preserved Ejection Fraction Using Three‐Dimensional Speckle‐Tracking Echocardiography and Pulmonary Artery Stiffness

ABSTRACT Objectives A novel index, termed the right ventricle (RV)‐pulmonary artery (PA) index, was established by integrating the longitudinal strain of the right ventricular free wall (RVFWLS) and the right ventricular ejection fraction (RVEF), both evaluated using three‐dimensional speckle‐tracking echocardiography (3D‐STE), with the stiffness of the pulmonary artery (PAS). This approach aims to enhance our understanding of the underlying mechanisms associated with heart failure with preserved ejection fraction (HFpEF). Methods The study comprised 80 patients diagnosed with HFpEF, 60 high‐risk patients without clinical heart failure (HF), and 50 healthy controls. Clinical data and pulmonary stiffness measurements were collected, and right ventricular function was evaluated using 3D‐STE. Furthermore, the corresponding RV‐PA coupling parameters were established. Statistical analyses were conducted using SPSS version 26.0 and R software, employing one‐way ANOVA, the Kruskal–Wallis H test, Pearson and Spearman correlation coefficients, multivariable linear regression, and receiver operating characteristic (ROC) curve analysis. Results Patients with HFpEF exhibited elevated levels of PAS, dilated right heart structures, and impaired right ventricular (RV) function when compared to both high‐risk and control groups. PAS was identified as an independent risk factor for RV dysfunction. Stratified diagnostic analysis revealed that the novel coupling index, RVEF/PAS, demonstrated exceptional diagnostic performance during the initial screening phase (AUC = 0.813) and maintained robust discriminatory power during the differentiation stage of the high‐risk population (AUC = 0.757). Both newly developed indices, RVEF/PAS and RVFWLS/PAS, exhibited significant positive correlations with tricuspid annular plane systolic excursion (TAPSE)/PASP ( r = 0.536, p = 0.004; r = 0.449, p = 0.019). The proposed stratified diagnostic model, characterized by a “primary screening‐refined discrimination” approach based on parameter characteristics, offers a novel strategy for the early detection of HFpEF. Conclusions The 3D‐STE method reliably assesses right ventricular function in patients with HFpEF, while pulmonary arterial compliance is effectively evaluated through PAS. The novel RV‐PA coupling indices, namely RVEF/PAS and RVFWLS/PAS, are developed by integrating these techniques, providing a stratified diagnostic strategy for the early detection of HFpEF. PAS is appropriate for initial screening in primary care settings, whereas RVEF/PAS offers precise diagnostic support in medical centers. Collectively, these methods establish a novel non‐invasive tool system for evaluating interactions between the right heart and pulmonary vasculature.