Enhancing Intermediate-Risk Stratification in Pulmonary Hypertension: CMR-Derived Quantification of Right...

To determine whether cardiovascular magnetic resonance (CMR)-derived stroke volume to end-systolic volume ratio (SV/ESV) improves prognostic stratification in pulmonary hypertension (PH) patients classified as intermediate-risk by the 2022 ESC/ERS four-strata model.

We retrospectively included patients with PH who underwent CMR, right heart catheterization (RHC) and complete clinical data. Individuals were categorized into intermediate-low (IML) and intermediate-high (IMH) risk groups according to the 2022 ESC/ERS simplified four-strata model. The composite endpoint of clinical worsening (CW) was defined as hospitalization for congestive heart failure or death. Survival analysis and model performance testing assessed the prognostic contribution of SV/ESV.

Among 120 PH patients (IML n = 76; IMH n = 44), the IMH-group demonstrated significantly impaired right ventricular (RV) systolic function, larger RV volumes, lower left ventricular volume, and reduced SV/ESV (all P < 0.05). SV/ESV independently predicted IMH-risk. Over a median follow-up of 62 months, 33 patients (28%) experienced CW. Patients with SV/ESV < 0.51 had significantly worse outcomes (Log-rank P = 0.001). Incorporation of SV/ESV significantly improved prognostic discrimination compared to the four-strata model alone, increasing Harrell's C-index from 0.60 to 0.74 and reducing the Akaike information criterion (AIC) from 289 to 272 (ΔC = 0.14, P = 0.008).

SV/ESV may serve as a noninvasive biomarker that provides incremental prognostic value for clinical deterioration in intermediate-risk PH patients.