Impact of the New Definition on the Prognosis of Patients With Pulmonary Hypertension Compared to the Classic Definition

Background and Objectives: The 2022 European Society of Cardiology (ESC)/European Respiratory Society (ERS) guidelines updated the definition of pulmonary hypertension (PH). This study aimed to evaluate implications of the new PH definition. Methods: A retrospective analysis of a single-center right heart catheterization registry (April 2016–July 2023) was conducted. Patients were classified using the classic definition (mean pulmonary arterial pressure [mPAP] ≥25 mmHg, pulmonary vascular resistance [PVR] >3 Wood units [WU]) and the new definition (mPAP >20 mmHg, PVR >2 WU). The primary outcome was a composite of cardiovascular death or heart failure (HF) hospitalization over a maximum follow-up of 5 years. Results: Among 314 patients (median age, 62.5 years; male, 50.3%), the new definition led to a 9.6% increase in diagnosis of pre-capillary PH (Pre-PH) and a 10.5% increase in combined pre-and post-capillary PH (Cpc-PH). Event discrimination was comparable between the 2 definitions, as assessed by the C-index and net reclassification improvement. Multivariable Cox regression, adjusted for age and sex, showed a lower risk of cardiovascular death or HF hospitalization under the new definition. Spline analyses indicated that risk increased from mPAP >20 mmHg and PVR >2 WU. Conclusions: The new definition increased PH diagnoses, particularly in Pre-PH and Cpc-PH, while maintaining comparable discriminative performance. Improved 5-year event-free survival observed under the new definition may be partly attributable to the inclusion of patients with milder disease. Notably, the risk progressively increased beyond mPAP >20 mmHg and PVR >2 WU, reinforcing the prognostic significance of the new thresholds.