Cardiac MRI optimizes risk stratification accuracy in connective tissue disease-associated pulmonary arterial hypertension: a retrospective cohort study

OBJECTIVES: The primary objective of this study is to investigate the potential of cardiac magnetic resonance (CMR) parameters to augment prognostic evaluation in patients with CTD-associated pulmonary arterial hypertension (CTD-PAH). METHODS: A retrospective, single-centre cohort study was conducted on 110 patients with CTD-PAH who were diagnosed via right heart catheterization between 2017 and 2023. These patients underwent CMR examinations based on clinical indications. RESULTS: After a mean follow-up period of 27 months, 27 patients experienced clinical deterioration events. After adjusting for age, sex and COMPERA 2.0 risk assessment model parameters, five CMR metrics were identified as independent risk factors for clinical deterioration in CTD-PAH patients. Receiver operating characteristic curve analysis showed that combining COMPERA 2.0 risk assessment model with CMR metrics improved predictive performance, with interventricular septum extracellular volume (IVS ECV) providing the greatest benefit among tissue metrics and right ventricular ejection fraction (RVEF) showing the most improvement among right heart function metrics. Kaplan-Meier（KM） survival curves revealed that patients with RVEF <39.2% and IVS ECV >31.4% had the poorest prognosis. Calibration curves indicated that integrating RVEF and IVS ECV significantly enhanced the accuracy and reliability of the COMPERA 2.0 risk assessment model in predicting 1-, 2- and 3-year event-free survival rates in CTD-PAH patients, with the C-index improving from 0.626 to 0.805. CONCLUSION: Combining RVEF and IVS ECV with COMPERA 2.0 risk assessment model significantly enhances the model's predictive accuracy for clinical deterioration in CTD-PAH patients.