Abstract Rationale Myositis-interstitial lung disease (ILD) infrequently leads to pulmonary hypertension (PH), yet emerging evidence suggests immune-mediated injury may also involve the pulmonary vasculature, contributing to PH. Immune-mediated endothelial remodeling, driven by myositis-specific and myositis-associated antibodies (MSA/MAA), has been proposed as a distinct pathogenic pathway, particularly in the absence of ILD. Quantitative CT (qCT)–derived vascular metrics can non-invasively characterize these changes, providing insights into early pulmonary vasculopathy in myositis. Methods We retrospectively analyzed 187 patients with myositis-ILD; quantitative vascular metrics were derived using Coreline software, including total blood volume (TBV), small-vessel (BV5), and medium-vessel (BV10) fractions, and their ratios (BV5/TBV, BV10/TBV, BV5/BV10). PH was defined by right-heart catheterization (RHC). Parenchymal measures were also compared between PH and non-PH patients. Results Of the 187 patients, 68 had complete RHC data (48 with PH and 20 without). The cohort consisted of 75% females with a mean age of 60.7 ± 12.1 years. Over 25.5 months, there were 23 deaths and 13 lung transplants. ANA was present in 48.5%, never in isolation, and often occurred with RNP, Jo-1, Ro52, RNA polymerase III, or RF. Common antibodies included RF and RNP (20.6% each), SS-A (16.2%), Jo-1 (13.2%), RNA polymerase III (11.8%), PL-7 and Ro52 (8.8%), and Scl-70 or CCP (7.4%). Anti-Jo-1, PL-7, and RNP showed distinct qCT vascular patterns. Anti-Jo-1 was associated with lower BV5/BV10 (p = 0.012), anti-PL-7 with lower BV5/TBV (p = 0.027), and anti-RNP with higher BV10/TBV (p = 0.039). No other antibodies showed significant associations. Fibrosis scores were similar between groups, but PH patients had lower BV5/BV10 ratios. BV5/BV10 ≤ 0.52 predicted PH with an AUC of 0.73 (p 0.001, 100% specificity, 48% sensitivity). A BV5/BV10 ratio 0.52 was associated with a 1.25-fold higher, but non-significant, odds ratio of developing PH (p = 0.66). Conclusion This study found that parenchymal changes were similar between myositis-ILD patients with and without PH; these findings support an immune-mediated vascular mechanism separate from fibrotic lung injury. The BV5/BV10 ratio has potential as a noninvasive radiomic biomarker for early detection and risk stratification. Serologic correlations further suggest the presence of certain antibodies can be linked to distal or proximal microvascular remodeling. For example, ANA may portend a more vascular phenotype overall. Integrating serologic profiles with quantitative imaging metrics may improve the early hemodynamic evaluation and management of PH in myositis. Prospective studies are warranted to validate these findings and future prognostic implications. This abstract is funded by: None
Omari et al. (Fri,) studied this question.