Computed tomography assessment of pharmacological lung volume reduction induced by bronchodilators in COPD

Abstract

Pharmacological lung volume reduction in COPD is an important goal in treatment with long-acting bronchodilators because in addition to airflow limitation, lung hyperinflation considerably affects COPD symptoms. Quantitative computed tomography (CT) simultaneously provides structural information about airway dimensions, emphysematous changes, and lung volumes, some of which are difficult to be evaluated by pulmonary function. Here, we evaluated changes in CT parameters and pulmonary function in 30 patients with COPD who underwent CT scans before and one year after starting tiotropium treatment and in 12 patients with COPD who were not treated with long-acting bronchodilators. Baseline pulmonary function and CT parameters did not differ between the two groups. One-year tiotropium therapy improved physiological-indices including residual volume (RV) and ratio of RV to total lung capacity (RV/TLC) (-235 mL, p = 0.005, and -2.9%, p = 0.0001, respectively), and CT-indices including wall area percent (WA%) and inner luminal area in right upper lobe apical and lower lobe basal segmental bronchi (-1.59%, p = 0.01, 2.27 mm(2), p = 0.0005; and -1.33%, p = 0.0008, 3.42 mm(2), p < 0.0001, respectively), low attenuation volume (LAV) and total lung volume (CT-TLV) (-92 mL, p = 0.0003, and -211 mL, p = 0.002, respectively). Changes in LAV, CT-TLV, RV, and RV/TLC were significantly greater in the tiotropium, than the non-bronchodilator group. The tiotropium-induced reduction in LAV correlated with the decrease in RV (ρ = 0.45, p = 0.01). Our findings not only indicate the value of the comprehensive CT measurements in assessing the effects of bronchodilators, including pharmacological lung volume reduction, but also further understanding of the structural changes underlying physiological improvements induced by bronchodilators.

Longitudinal changes in structural abnormalities using MDCT in COPD: do the CT measurements of airway wall thickness and small pulmonary vessels change in parallel with emphysematous progression?

“…Although longitudinal studies about health status or lung function in COPD have been performed, 15 the longitudinal changes in structural abnormalities in COPD have not been fully explored. Studies on emphysema progression have been addressed, 16 – 18 but studies about the changes in airway disease 19 or vascular remodeling are rare. 20 The association between alveolar destruction, airway disease, and pulmonary vascular change also remains unknown.…”

Comparison of airway dimensions with once daily tiotropium plus indacaterol versus twice daily Advair® in chronic obstructive pulmonary disease

“…To our knowledge, this is the first study to demonstrate the beneficial effects of tiotropium and indacaterol compared with Advair ® for airway geometry in COPD. Quantitative CT analysis is important for assessing treatment responses [18,23] because it can provide information about airway dimensions and emphysematous changes [13,24]. Combination of tiotropium and indacaterol showed significant greater dilation of the luminal area and reduction in airway wall thickness than Advair ® .…”

Biomarkers in chronic obstructive pulmonary disease: confusing or useful?

“…Radiology can also study the airways, indicating responses to bronchodilator therapy22 and the presence and distribution of accompanying bronchiectasis, which is also a predictor of mortality23 (although the reasons are currently unclear).…”