Objective To prospectively investigate whether differences in pulmonary vasculature exist in systemic sclerosis (SSc) and how they are distributed in patients with different pulmonary function.
Methods Seventy-four patients with SSc undergoing chest CT scan for interstitial lung disease (ILD) screening or follow-up were prospectively enrolled. A thorough clinical, laboratory and functional evaluation was performed the same day. Chest CT was spirometry gated at total lung capacity and images were analysed by two automated software programs to quantify emphysema, ILD patterns (ground-glass, reticular, honeycombing), and pulmonary vascular volume (PVV). Patients were divided in restricted (FVC% <80, DLco%<80), isolated DLco% reduction (iDLco- FVC%≥80, DLco%<80) and normals (FVC%≥80, DLco%≥80). Spearman ρ, Mann-Whitney tests and logistic regressions were used to assess for correlations, differences among groups and relationships between continuous variables.
Results Absolute and lung volume normalised PVV (PVV/LV) correlated inversely with functional parameters and positively with all ILD patterns (ρ=0.75 with ground glass, ρ=0.68 with reticular). PVV/LV was the only predictor of DLco at multivariate analysis (p=0.007). Meanwhile, the reticular pattern prevailed in peripheral regions and lower lung thirds, PVV/LV prevailed in central regions and middle lung thirds. iDLco group had a significantly higher PVV/LV (2.2%) than normal (1.6%), but lower than restricted ones (3.8%).
Conclusions Chest CT in SSc detects a progressive increase in PVV/LV as DLco decreases. Redistribution of perfusion to less affected lung regions rather than angiogenesis nearby fibrotic lung may explain the results. Further studies to ascertain whether the increase in PVV/LV reflects a real increase in blood volume are needed.
- systemic sclerosis
- pulmonary fibrosis
- disease activity
- cardiovascular disease
- arterial hypertension
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Handling editor Josef S Smolen
MO and CB contributed equally.
Contributors Study concepts/study design or data analysis/interpretation: MO, CB, MP, MM-C. Manuscript drafting or manuscript revision for important intellectual content: MO, CB, MP, FL, SC, and MM-C. Agrees to ensure any questions related to the work are appropriately resolved: all authors. Literature research: MO, CB, AB, ST and MM-C. Clinical studies: MO, CB, GCa, GCi, GCu, AF, DG, MB, SB-R and MM-C. Data analysis: MO and CB. Software use: MO. Manuscript editing: MO, CB, FL, SB-R, SC and MP. Manuscript final version approval: all authors.
Funding This study received grants from Gruppo Italiano Lotta Sclerodermia and from Fondazione Italiana Ricerca Artrite.
Competing interests MO reports grants from Gruppo Italiano Lotta Sclerodermia (GILS), grants from Fondazione Italiana Ricerca Artrite (FIRA), during the conduct of the study; grants from Menarini Foundation, personal fees from Novartis, outside the submitted work. CB and DG report personal fees from Actelion, outside the submitted work. MM-C reports grants from FIRA, grants from GILS, during the conduct of the study; grants and personal fees from Actelion, personal fees from Biogen, personal fees from Bayer, personal fees from Boehringer Ingelheim, personal fees from CSL Behring, personal fees from Eli-Lilly, outside the submitted work. ST reports grants and personal fees from Roche, personal fees from Boehringer-Ingelheim, outside the submitted work. GCa, GCi, GCu, AF, SC, SB-R, AB, MB and FL have no COI disclosures.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Patient consent for publication Not required.
Ethics approval The study was approved by Comitato Etico Area Vasta Toscana Centro (CAEVC), protocol 12300.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon reasonable request. All data relevant to the study are included in the article or uploaded as supplementary information. Not all data can be shared publicly because of privacy laws. Data are available from the Ethics Committee for researchers who meet the criteria for access to confidential data. Please refer to the corresponding author.