Abstract
In asthma patients, magnetic resonance imaging (MRI) and the lung clearance index (LCI) have revealed persistent ventilation heterogeneity, although its relationship to asthma control is not well understood. Therefore, our goal was to explore the relationship of MRI ventilation defects and the LCI with asthma control and quality of life in patients with severe, poorly controlled asthma.
18 patients with severe, poorly controlled asthma (mean±sd 46±12 years, six males/12 females) provided written informed consent to an ethics board approved protocol, and underwent spirometry, LCI and 3He MRI during a single 2-h visit. Asthma control and quality of life were evaluated using the Asthma Control Questionnaire (ACQ) and Asthma Quality of Life Questionnaire (AQLQ). Ventilation heterogeneity was quantified using the LCI and 3He MRI ventilation defect percent (VDP).
All participants reported poorly controlled disease (mean±sd ACQ score=2.3±0.9) and highly heterogeneous ventilation (mean±sd VDP=12±11% and LCI=10.5±3.0). While VDP and LCI were strongly correlated (r=0.86, p<0.0001), in a multivariate model that included forced expiratory volume in 1 s, VDP and LCI, VDP was the only independent predictor of asthma control (R2=0.38, p=0.01). There was also a significantly worse VDP, but not LCI in asthma patients with an ACQ score >2 (p=0.04) and AQLQ score <5 (p=0.04), and a trend towards worse VDP (p=0.053), but not LCI in asthma patients reporting ≥1 exacerbation in the past 6 months.
In patients with poorly controlled, severe asthma MRI ventilation, but not LCI was significantly worse in those with worse ACQ and AQLQ.
Abstract
MRI ventilation defects, but not LCI, are worse in patients with worse asthma control and asthma-related QoL http://ow.ly/4n9uip
Footnotes
This article has supplementary material available from erj.ersjournals.com
Clinical trial: This study is registered at clinicaltrials.gov with identifier number NCT02263794.
Support statement: This research was undertaken, in part, thanks to salary funding from the Canada Research Chairs program support of P. Nair (Canada Research Chair in Inflammometry), Canadian Institutes of Health Research (CIHR) New Investigator Award support for G. Parraga and Canadian Respiratory Research Network support for S. Svenningsen. Ongoing research funding from a CIHR Operating Grant (MOP 201309) and pilot study funding from the Canadian Lung Association are also gratefully acknowledged. Funding information for this article has been deposited with FundRef.
Conflict of interest: None declared.
- Received February 22, 2016.
- Accepted April 13, 2016.
- Copyright ©ERS 2016