CONGRESS ABSTRACT

Background In patients with pulmonary arterial hypertension (PAH) current European guidelines recommend achieving a low-risk profile, primarily based on World Health Organization functional class (WHO-FC), 6-minute walk distance (6MWD), and natriuretic peptides (BNP/NT-proBNP). However, these non-invasive parameters are influenced by age. We investigated the impact of age on treatment response and evaluated the prognostic role of haemodynamic-based risk assessments. Methods Treatment-naïve PAH patients from a single-centre registry were included, stratified by age. Clinical, functional, and haemodynamics were assessed at baseline and after initial PAH- targeted therapy. Prognostic discrimination was performed using non-invasive (ESC/ERS 4- strata, REVEAL Lite 2) and haemodynamic-based risk models (including a purely haemodynamic -RHC- risk tool) with Cox regression and c-statistics. Results 794 PAH patients were enrolled. Elderly individuals exhibited worse WHO-FC, higher BNP/NT- proBNP levels, and shorter 6MWD, despite lower right ventricular (RV) afterload, likely due to comorbidities and worse RV function. Improvement of WHO-FC, BNP/NT-proBNP, and 6MWD is lower in the elderly, despite comparable haemodynamic changes across the age groups. In older patients, non-invasive risk tools overestimated RHC risk tool severity and demonstrated a reduced prognostic accuracy. In patients >65 years reaching a low-risk haemodynamic profile, non-invasive risk tools were of no added prognostic value. Conversely, haemodynamics provided independent prognostic information in younger patients. Conclusions Haemodynamics is less influenced by age than non-invasive risk assessment and is of added prognostic value to non-invasive assessment in younger patients. Achieving a low-risk haemodynamic profile can be a valid therapeutic target when non-invasive criteria are not met in patients >65 years.