Echocardiographic TAPSE/PAPs Ratio Outperforms Severe PAPs for Predicting Mortality in Idiopathic Pulmonary Fibrosis

Background: The conventional echocardiographic definition of elevated pulmonary pressure (systolic pulmonary artery pressure, PAPs ≥ 40 mmHg) reflects afterload but does not capture right ventricular adaptation. The TAPSE/PAPs ratio integrates contractile function with pulmonary load, but head-to-head comparisons with PAPs ≥ 40 mmHg in real-world IPF cohorts are lacking. Methods: Single-center retrospective cohort study of consecutive patients with IPF diagnosed according to 2018 ATS/ERS/JRS/ALAT guidelines and complete baseline TAPSE and PAPs measurements. The optimal TAPSE/PAPs threshold for predicting all-cause mortality was identified by ROC analysis (Youden index). Survival was analyzed by Kaplan–Meier and Cox proportional hazards regression. Results: Results: Among 198 IPF patients, 74 (37.4%) had complete echocardiographic data; 21 died (28.4%). ROC analysis identified an optimal TAPSE/PAPs cutoff of ≤ 0.4 mm/mmHg (AUC 0.769; sensitivity 67%, specificity 87%). RV–PA uncoupling was associated with higher mortality (66.7% vs 13.2%) and shorter mean survival (67.5 vs 102.2 months; log-rank p = 0.004), and remained an independent predictor after adjustment for age and smoking (adjusted HR 2.93, 95% CI 1.14–7.57, p = 0.026). In contrast, PAPs ≥ 40 mmHg did not separate survival curves (log-rank p = 0.26) nor predict mortality after adjustment (adjusted HR 1.73, p = 0.27). Conclusions: In a real-world IPF cohort, the simple non-invasive TAPSE/PAPs ratio outperformed the conventional PAPs ≥ 40 mmHg definition for predicting all-cause mortality. RV–PA uncoupling defined by TAPSE/PAPs ≤0.4 mm/mmHg identifies a high-risk IPF phenotype and warrants routine assessment, pending prospective multicenter validation.