CT and Functional MRI to Evaluate Airway Mucus in Severe Asthma
Document Type
Article
Publication Date
6-1-2019
Journal
Chest
Volume
155
Issue
6
First Page
1178
Last Page
1189
URL with Digital Object Identifier
https://doi.org/10.1016/j.chest.2019.08.004
Abstract
BACKGROUND: Intraluminal contributor(s) to airflow obstruction in severe asthma are patient-specific and must be evaluated to personalize treatment. The occurrence and functional consequence of airway mucus in the presence or absence of airway eosinophils remain undetermined.
OBJECTIVE: The objective of this study was to understand the functional consequence of airway mucus in the presence or absence of eosinophils and to identify biomarkers of mucus-related airflow obstruction.
METHODS: Mucus plugs were quantified on CT scans, and their contribution to ventilation heterogeneity (using MRI ventilation defect percent [VDP]) was evaluated in 27 patients with severe asthma. Patients were dichotomized based on sputum eosinophilia such that the relationship between mucus, eosinophilia, and ventilation heterogeneity could be investigated. Fractional exhaled nitric oxide (Feno) and related cytokines in sputum were measured.
RESULTS: Mucus plugging was present in 100% of asthma patients with sputum eosinophils and 36% of those without sputum eosinophils (P = .0006) and was correlated with MRI VDP prebronchodilator (r = 0.68; P = .0001) and postbronchodilator (r = 0.72; P < .0001). In a multivariable regression, both mucus and eosinophils contributed to the prediction of postbronchodilator MRI VDP (R
CONCLUSIONS: Both airway eosinophils and mucus can contribute to ventilation heterogeneity in patients with severe asthma. Patients in whom mucus is the dominant cause of airway obstruction have evidence of an upregulated IL-4/IL-13 pathway that could be identified according to increased Feno level.
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Notes
This is an author-accepted version of this manuscript initially published by Elsevier available at: https://doi.org/10.1016/j.chest.2019.02.403https://doi.org/10.1016/j.chest.2019.08.004