Prognostic Value of the RVFWLS/PASP Ratio in Pulmonary Arterial Hypertension

Background: The Right Ventricular Free Wall Longitudinal Strain/Pulmonary Arterial Systolic Pressure (RVFWLS/PASP) ratio is a novel echocardiographic parameter for assessing right ventricular–pulmonary artery (RV-PA) coupling. Its prognostic role in patients with pulmonary arterial hypertension (PAH) remains poorly defined. This study aimed to explore the prognostic value of RVFWLS/PASP in PAH. Methods: A retrospective cohort study was conducted involving patients with PAH at Shanghai Pulmonary Hospital and Nanyang Second People's Hospital from December 2009 to October 2024.The RVFWLS/PASP ratio is calculated, where the numerator (RVFWLS) is derived using speckle tracking echocardiography, and the denominator (PASP) is estimated based on the tricuspid regurgitation velocity. The primary endpoint was event-free survival, with events defined as all-cause mortality, lung transplantation, rehospitalization for right heart failure, or escalation of targeted therapy due to clinical deterioration. Cox regression analysis was used to identify and validate RVFWLS/PASP characteristics in patients with different outcomes. Kaplan-Meier survival analysis was employed to evaluate the additive value of RVFWLS/PASP to previously established risk models. Results: A total of 216 adult PAH patients were enrolled. The median follow-up time was 31 months. The survival rate of patients in the lower RVFWLS/PASP group was significantly worse than those in the higher RVFWLS/PASP group (Log-rank P <0.05). Multivariate Cox regression demonstrated that after adjusting for other prognostic factors,RVFWLS/PASP ratio (HR = 0.20, 95% CI: 0.04-0.92, p = 0.039) and CTD-PH diagnosis (HR = 2.09, 95% CI: 1.36-3.22, p < 0.001) remained independent predictors of adverse clinical events. RVFWLS/PASP enabled further risk stratification of patients classified as low-risk by established models. Conclusion: The echocardiographic parameter RVFWLS/PASP serves as an independent determinant of long-term prognosis in patients with PAH, indicating that improved RV-PA coupling is significantly associated with better clinical outcomes. RVFWLS/PASP provides incremental value for risk stratification and may demonstrate heterogeneous utility across different clinical subgroups.