On the role of abnormal DL(CO) in ex-smokers without airflow limitation: symptoms, exercise capacity and hyperpolarised helium-3 MRI.

TitleOn the role of abnormal DL(CO) in ex-smokers without airflow limitation: symptoms, exercise capacity and hyperpolarised helium-3 MRI.
Publication TypeJournal Article
Year of Publication2013
AuthorsKirby, M, Owrangi, A, Svenningsen, S, Wheatley, A, Coxson, HO, Paterson, NAM, McCormack, DG, Parraga, G
JournalThorax
Volume68
Issue8
Pagination752-9
Date Published2013 Aug
ISSN1468-3296
KeywordsAged, Aged, 80 and over, Antimetabolites, Carbon Monoxide, Diffusion Magnetic Resonance Imaging, Exercise Tolerance, Female, Follow-Up Studies, Forced Expiratory Volume, Helium, Humans, Male, Middle Aged, Plethysmography, Pulmonary Disease, Chronic Obstructive, Questionnaires, Respiratory Function Tests, Smoking, Tomography, X-Ray Computed, Vital Capacity
Abstract

BACKGROUND: The functional effects of abnormal diffusing capacity for carbon monoxide (DLCO) in ex-smokers without chronic obstructive pulmonary disease (COPD) are not well understood.OBJECTIVE: We aimed to evaluate and compare well established clinical, physiological and emerging imaging measurements in ex-smokers with normal spirometry and abnormal DLCO with a group of ex-smokers with normal spirometry and DLCO and ex-smokers with Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage I COPD.METHODS: We enrolled 38 ex-smokers and 15 subjects with stage I COPD who underwent spirometry, plethysmography, St George's Respiratory Questionnaire (SGRQ), 6 min Walk Test (6MWT), x-ray CT and hyperpolarised helium-3 ((3)He) MRI. The 6MWT distance (6MWD), SGRQ scores, (3)He MRI apparent diffusion coefficients (ADC) and CT attenuation values below -950 HU (RA950) were evaluated.RESULTS: Of 38 ex-smokers without COPD, 19 subjects had abnormal DLCO with significantly worse ADC (p=0.01), 6MWD (p=0.008) and SGRQ (p=0.01) but not RA950 (p=0.53) compared with 19 ex-smokers with normal DLCO. Stage I COPD subjects showed significantly worse ADC (p=0.02), RA950 (p=0.0008) and 6MWD (p=0.005), but not SGRQ (p=0.59) compared with subjects with abnormal DLCO. There was a significant correlation for (3)He ADC with SGRQ (r=0.34, p=0.02) and 6MWD (r=-0.51, p=0.0002).CONCLUSIONS: In ex-smokers with normal spirometry and CT but abnormal DLCO, there were significantly worse symptoms, 6MWD and (3)He ADC compared with ex-smokers with normal DLCO, providing evidence of the impact of mild or early stage emphysema and a better understanding of abnormal DLCO and hyperpolarised (3)He MRI in ex-smokers without COPD.

DOI10.1136/thoraxjnl-2012-203108
Alternate JournalThorax
PubMed ID23604381
Grant ListCIF#97687 / / Canadian Institutes of Health Research / Canada