Abstract Body (Do not enter title and authors here): Background: In advanced stages of heart failure with preserved ejection fraction (HFpEF), right ventricular (RV) function declines, leading to abnormal RV-pulmonary artery (PA) coupling. Current 2D echocardiography only assesses longitudinal function, overlooking RV crescentic geometry and 3D myocardial function. We aimed to assess the prognostic implications of RV function and abnormal RV-PA coupling using 3D echocardiography in HFpEF patients.
Methods: Between 2021 and 2023, we prospectively analyzed 202 HFpEF patients (74.1 ± 10.4 years old, 57.4% female) at a single tertiary hospital. HFpEF was defined by HFA-PEFF criteria. We assessed 3D RV ejection fraction (RVEF), pulmonary artery systolic pressure (PASP), tricuspid annular plane systolic excursion (TAPSE), and 3D RV-PA coupling index (RVEF/PASP). The primary outcome was a composite of all-cause death and hospitalization due to heart failure.
Results: During the median follow-up of 2.0 (range: 1.7 – 2.1) years, 36 (17.8%) primary outcomes occurred. Patients with outcomes had higher PASP, lower 3D RVEF and RV-PA coupling index compared to those without. The E/e` ratio and TAPSE were not different between the groups. Patients with RVEF < 45%, and abnormal 3D RV-PA coupling showed a higher incidence of primary outcomes (log-rank p = 0.048 and p=0.0004, respectively), while whereas TAPSE < 17 mm was not associated with outcomes (log-rank p = 0.89). In the multivariable analysis, PASP and RVEF were associated with poor outcomes, and as a result, the abnormal 3D RV-PA coupling index was significantly associated with poor outcomes (adjusted hazard ratio: 0.185, 95% confidence interval: 0.075 - 0.454, p <0.001).
Conclusions: Reduced RVEF and abnormal RV-PA coupling assessed by 3D echocardiography have prognostic significance in HFpEF patients. Maintaining RV function and RV-PA coupling is crucial for prognosis and should be therapeutic targets or monitoring imaging markers for HFpEF.