Frontiers in cardiovascular medicine,2026 Oct 14
- Introduction: We hypothesized that differences in pulmonary hemodynamics during acute vasoreactive testing (AVT), beyond the conventional Sitbon criteria, may be described as pulmonary vasoreactive reserve (VRR) that could be used to assess disease severity and prognosis in idiopathic pulmonary arterial hypertension (IPAH) patients. The study aimed to evaluate the clinical significance of VRR in patients with IPAH.
- Methods: Ninety adult IPAH patients (40.4 ± 14.6 years, 14.3% males) from a prospective single-center PAH registry were divided into three groups based on mean pulmonary artery pressure (mPAP) decrease during AVT: Group I (n = 25): ΔmPAP > 30%; Group II (n = 13): ΔmPAP 15%-30%; and Group III (n = 52): ΔmPAP < 15%. A comparison was performed between the standard model of survival prediction using the 2022 European Society of Cardiology/European Respiratory Society (ESC/ERS) three-strata risk stratification scale and the experimental model with ΔmPAP grading.
- Results: The absolute value of ΔmPAP was 21 mmHg (14; 28) in Group I, 11 mmHg (10; 12) in Group II, and only 2.5 mm Hg (1; 4.5) in Group III. The Δ%mPAP significantly differed in low-, intermediate-, and high-risk 2022 ESC/ERS three-strata categories (32.4 (12.3; 42.2) vs. 12.9 (3.01; 28.2) vs. 4.8% (1.8; 8.9), p = 0.0009). Significant association was revealed between the Δ%mPAP and pulmonary artery compliance (r = 0.30; p = 0.0045), pulmonary artery distensibility (r = 0.37, p = 0.0058), and cardiopulmonary exercise test parameters. During a follow-up of 2.32 years (1.04; 4.06), 17 (18.8%) patients died. The survival rate was 93%, 83%, 78%, 62%, and 55% at 1, 3, 5, 7, and 10 years, respectively. The degree of Δ%mPAP [heart rate (HR) 5.99 (1.37-26.2), p = 0.017], N-terminal pro-brain-type natriuretic peptide > 1,100 pg/mL [HR 8.1 (1.67-39.2), p = 0.009], and the number of PAH-specific drugs [HR 0.07 (0.018-0.3), p = 0.0003] were considered independent predictors of survival. The inclusion of Δ%mPAP slightly improved prognostic value for the 2022 ESC/ERS three-strata risk stratification scale in comparison with the standard 2022 ESC/ERS three-strata approach (mean absolute percentage error, MAPE = 9.66%; C-index = 0.7552742616033755 vs. MAPE = 9.82%; C-index = 0.7510548523206751).
- Conclusion: The assessment of VRR may warrant further investigation as an additional marker of the disease severity and prognosis in IPAH patients.