Hemodynamic Patterns in Interstitial Lung Disease: A Snapshot of Clinical Practice and a Roadmap for Future Trials

Interstitial lung disease (ILD) complicated by pulmonary hypertension (PH) is associated with poor outcomes. However, real-world data characterizing the hemodynamic profiles of ILD patients undergoing right heart catheterization (RHC) remain limited. We retrospectively analyzed ILD patients who underwent RHC between 2006 and 2024. Hemodynamic profiles were assessed according to the 5th, 6th, and 7th World Symposium on Pulmonary Hypertension (WSPH) definitions and for severe PH (pulmonary vascular resistance [PVR] > 5 Wood units). Correlations between pulmonary function testing (PFT) variables and PVR were explored, and baseline characteristics were compared across groups stratified by PH severity. There were 3541 ILD patients evaluated of whom 12.2% underwent RHC. Among 371 patients with available RHC data and pulmonary arterial wedge pressure (PAWP) ≤ 15 mmHg, 49.6%, 54.4%, and 69.4% met the 5th, 6th, and 7th WSPH criteria for precapillary PH, respectively, while 31.3% exhibited severe PH. Correlations between diffusing capacity for carbon monoxide (DLco)%, and forced vital capacity (FVC)%/DLco% ratio with PVR were weak. Our findings highlight the heterogeneous hemodynamic landscape of ILD-PH in clinical practice and underscore the need for heightened vigilance and lower thresholds for RHC. These real-world data can inform future clinical trial design, screening strategies, and management decisions for ILD-PH.