Bronchial artery hypertrophy is common in lung fibrosis and associated with mutations of telomere-related genes

Fibrosing interstitial lung diseases (ILD) associated with telomere-related gene (TRG) mutations exhibit extra-thoracic features suggesting systemic angiogenesis abnormalities. We investigated the bronchial arterial (BA) circulation in TRG-mutated ILD patients. We measured diameters of right (R) and left (L) BA at aorta’s origin and of medial thoracic arteries on chest angioCT in ILD patients with (ILD TRG+, n=46) and without (ILD TRG -, n=44) TRG mutations, and in age- and sex-matched controls without ILD (n=49). BA hypertrophy (BAH) was defined as a BA diameter ≥2.0mm. While diameters of R and L medial thoracic arteries were similar in the 3 groups, median RBA diameter was larger in ILD TRG+ (2.0 mm IQR [1,6-2,6]) and ILD TRG- (1.8 [1.5-2.1]) patients than in controls (1.4 [1.2-1.7] p<0.001). A similar difference was seen for LBA diameter. There was no difference between TRG+ and TRG- patients. RBAH was more frequent in ILD TRG+ (48%), than in ILD TRG- (25%, p=0.05) and controls (6%, p<0.001). Data were similar for LBAH (31%, 14%, 2%, p<0.001). In multivariate analysis, BAH was associated with male gender (OR=7,64, 95%CI: 1.36-72.2, p=0.039), PPFE HRCT pattern (OR=8,21, 95%CI: 1.53-70.7, p=0.025) and increased PaO2 (OR=1.05, 95%CI: 1.01-1.10, p=0.018). BAH was not a predictive factor for death nor lung transplant. RBA and LBA diameters did not correlate with HRCT ILD extent and lung function. LBA diameter, but not RBA, positively correlated with mean PAP (R=0.585, p=0.01) and pulmonary vascular resistances (R=0.855, p<0.0001). <bold>Conclusion:</bold> BA are hypertrophied in patients with fibrotic ILD, all the more so in patients TRG+. PPFE pattern is an independent risk factor for BAH.