Predictive Power of Pulmonary Artery Stiffness - Right Ventricular Interplay, but not Pulmonary Vascular Resistance, in Mild Pulmonary Hypertension: A PVRI GoDeep meta-registry analysis.

Abstract

Background: Pulmonary vascular diseases are characterized by mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance (PVR), both reflecting the steady-flow component of right ventricular (RV) afterload while neglecting pulsatile elements. Pulmonary artery compliance (PAC) and arterial elastance (E_a) capture complementary aspects of pulmonary vascular load, whereas stroke volume index (SVI) reflects RV functional adaptation. The prognostic significance of these integrated parameters remains incompletely understood, particularly in early-stage disease.

Research question: Do PAC, E_a, and SVI predict mortality independently of PVR in patients with mild PH and across the full spectrum of pulmonary hypertension (PH)?

Methods: Using the international PVRI GoDeep meta-registry, we first evaluated the prognostic relevance of PAC, E_a, and SVI in patients with mild PH, defined as a mPAP >20 and <25 mmHg. Subsequently, these analyses were extended to the overall PH population across the full spectrum of disease severity. Subgroup analyses were performed according to PH etiology. PAC was calculated as the ratio of SV to pulmonary arterial pulse pressure, and E_a as end-systolic pressure divided by SV.

Results: In patients with mild PH (n = 1,097), neither mPAP nor PVR predicted mortality (both p>0.05). In contrast, E_a, PAC, SVI, and heart rate demonstrated independent prognostic value. Expanding the analysis to 16,899 patients across PH groups 1-5, these parameters remained significantly associated with survival, independent of PVR/TPR and after adjustment for multiple potential confounders. Consistent findings were observed across etiological subgroups and IPAH/hPAH.

Interpretation: Parameters integrating pulsatile vascular load and interdependent RV function possess predictive power independent of PVR/TPR across the full spectrum of PH. Moreover, they allow meaningful risk stratification in mild PH patients, where conventional parameters lack discriminative prognostic power.