Reevaluating risk assessment in connective tissue disease-associated pulmonary arterial hypertension: The prognostic superiority of stroke volume index

Objective To evaluate the prognostic value of stroke volume index (SVI) compared to cardiac index (CI) in risk stratification and outcome prediction in connective tissue disease-associated pulmonary arterial hypertension (CTD-PAH). Methods We performed a retrospective analysis of patients diagnosed with CTD-PAH through right heart catheterization (RHC) from two Chinese medical centers. This retrospective study analyzed 206 CTD-PAH patients, with risk stratification performed using the 2018 World Symposia on Pulmonary Hypertension (WSPH) framework. Restricted cubic splines (RCS) and log-rank tests were utilized to identify the optimal SVI cutof values for categorizing patients into low-, intermediate-, and high-risk groups. Kaplan-Meier (KM) curves were used to analyze survival rates and event-free survival. Receiver operating characteristic (ROC) analysis was used to assess the predictive accuracy of diferent models for prognostic outcomes. Results SVI was categorized into low-risk (SVI ≥ 33.35 mL/m 2 ), intermediate-risk (24.66 mL/m 2 ≤ SVI < 33.35 mL/m 2 ), and high-risk (SVI < 24.66 mL/m 2 ) groups. Among the 206 CTD-PAH patients, 55 exhibited discrepancies in risk stratification between CI and SVI. SVI-based stratification provided more accurate risk categorization and demonstrated superior predictive value compared to CI, showing significant diferences in both survival and event-free survival rates across the groups. Conclusion SVI enhances risk stratification and prognosis prediction in CTD-PAH by efectively distinguishing patients at higher risk for adverse outcomes.