Impaired pulmonary function associated with subclinical myocardial injury in primary Sjögren's syndrome: a preliminary cardiac magnetic resonance study.

BACKGROUND: Primary Sjögren's syndrome (pSS) is a systemic autoimmune disease where cardiac involvement is increasingly recognized but challenging for screening and detection. Cardiac magnetic resonance (CMR) is a powerful tool for identifying such impairments but had limited clinical application. Therefore, this study investigated the relationship between clinical characteristics particularly pulmonary function tests (PFTs) and cardiac MRI parameters for identifying pSS patients at risk of subclinical myocardial injury.

METHODS: This cross-sectional study included 48 pSS patients without overt cardiac symptoms who underwent both CMR and PFTs. According to interstitial lung disease (ILD) status, patients were categorized into the pSS-ILD group (ILD, n = 37) and the pSS-nonILD (n = 11) group based on high-resolution CT results. The clinical and CMR parameters were also analyzed. Impaired PFT was defined as predicted diffusing capacity for carbon monoxide (DLCO) < 70% or forced vital capacity (FVC) < 80%. Correlation analysis, univariate and multivariate linear regression analyses were performed to assess associations between PFT results, inflammatory markers, and myocardial tissue characteristics.

RESULTS: Patients in the pSS-ILD group had significantly worse PFT results than the pSS-nonILD group. Impaired PFT and an elevated erythrocyte sedimentation rate (ESR) were independently associated with higher native T1 values after adjustment for age, sex, BMI, disease duration, and disease activity (impaired PFT: β = 103.49, P = 0.013; abnormal ESR: β = 84.63, P = 0.001). Among PFT parameters, DLCO showed the strongest negative correlation with native T1 (r = - 0.458, P = 0.001). Subgroup analysis confirmed that impaired PFT was correlated with higher T1 values in both ILD and nonILD pSS patients.

CONCLUSION: The preliminary study revealed that impaired pulmonary function and abnormal ESR are independently associated with increased cardiac T1 mapping in pSS. Although future large-scale studies should be performed to validate the results, this study suggested that pSS patients with specific presentations may benefit from further cardiac evaluation with CMR. Key Points • Pulmonary function test results significantly correlated with myocardial fibrosis indicator (native T1 mapping) on CMR. • Impaired PFT and elevated ESR independently associated with higher native T1 value in pSS patients. • In both ILD and nonILD pSS patients, impaired PFT exhibited moderate correlations with T1 mapping, suggesting its utility across the different patient spectrum.