Computed tomography-derived pulmonary blood volume distribution may be modifiable in asthma.

BACKGROUND: A smaller relative volume of the peripheral pulmonary vasculature in asthma, termed "vascular pruning", has been linked to greater disease severity, exacerbations, and airflow obstruction. It is not known whether this is reversible. Therefore, the study objective was to determine whether "loss" of computed tomography (CT) measures of peripheral pulmonary vasculature is a modifiable feature of asthma pathophysiology by assessing its response to dupilumab. METHODS: 27 adults with moderate-to-severe asthma received dupilumab (n=19) or placebo (n=8) every 2 weeks for 16 weeks. Chest CT scans acquired at baseline and follow-up were analysed to quantify pulmonary blood vessel volumes categorised by cross-sectional area (≤5 mm2 as BV5 and ≥10 mm2 as BV10). These volumes were reported relative to the total blood volume (TBV) as BV5% and BV10%. Change in blood vessel volumes from baseline to follow-up were evaluated and correlated with changes in patient-reported outcomes, type-2 inflammatory biomarkers and measurements of airway structure and function. RESULTS: Following dupilumab treatment (but not placebo), BV5% increased by 1.0% (95% CI -0.2% to 4.5%, p=0.02) and BV10% decreased by 1.0% (95% CI -3.6% to 0.7%, p=0.03). The between-group difference in median change was 3.0% for BV5% (95% CI 0.6% to 5.5%; p=0.008) and -3.0% for BV10% (95% CI -5.2% to -1.0%; p=0.007). In dupilumab-treated participants, the increase in BV5% and decrease in BV10% was associated with improved Asthma Control Questionnaire-5, forced expiratory volume in 1 s, fraction of exhaled nitric oxide and sputum eosinophil percentage (all p<0.05). CONCLUSION: A redistribution of pulmonary blood volume toward smaller vessels was observed following dupilumab, suggesting that CT-derived pulmonary vascular measurements may be modifiable in asthma.