Computed tomographic airway morphology after targeted lung denervation treatment in COPD
Résumé
This post-hoc analysis of the AIRFLOW-2 trial investigated the changes in airway CT-parameters after targeted lung denervation (TLD) and whether these changes are associated with treatment response. In the treatment group (n = 32), an improvement in air trapping was significantly associated with an improvement in residual volume (RV). Furthermore, improvements in Pi10 and airway lumen were significantly associated with an improvement in both RV and FEV1. Our results could suggest that when improving airway characteristics like decreasing airway wall thickness and increasing the airway lumen, this leads to less air trapping and an improvement in clinical outcomes.
The bronchoscopic targeted lung denervation (TLD) treatment is a potential new therapy for COPD patients with frequent exacerbations [[1]]. So far, positive outcomes of the treatment were reported on the frequency of COPD exacerbations and stabilization of lung function and deterioration of lung function decline in the longer term [2, 3, 4, 5]. By use of radiofrequency the TLD treatment aims to disrupt the peribronchial vagal innervation of the airways and consequently decrease the release of acetylcholine. Potentially, the treatment could also improve airway characteristics like airway wall thickness and consequently air trapping in the lung. However, this has not been investigated so far. Therefore, the aim of this post-hoc analysis of the AIRFLOW-2 trial (NCT20258459) [[4]] was to investigate the changes in airway CT-parameters after the TLD treatment and furthermore whether these changes are associated with treatment response.
The AIRFLOW-2 trial investigated the safety and impact of the TLD treatment by comparing the treatment with sham-controlled placebo [[4]]. Ethics committees of participating hospitals approved the trial and all 82 patients provided informed consent. As part of the trial, computed tomography (CT) scans were performed at baseline and after 1 year follow-up. Furthermore, patients performed spirometry, body plethysmography and filled out the St. George's respiratory questionnaire (SGRQ) at the same timepoints. For this post-hoc analysis, a quantitative CT-scan analysis (QCT) was performed using LungQ-software (Thirona, The Netherlands). Outcomes of the quantitative analysis were lung volumes, quantification of emphysema and air trapping and airway measurements (Pi10, airway wall thickness and lumen diameter).
In total 66 patients had QCT analysable scans at both baseline and 1 year follow-up and were included (mean age 64 ± 7, FEV1 0.94 ± 0.28 L, SGRQ total score 55 ± 16; see Table S1, Online supplement). Baseline characteristics did not differ between the patients with QCT analysable or non-analysable scans (Table S2, Online supplement). In the treatment group, 32 patients had analysable inspiratory scans (of which 24 had both in- and expiratory scans) and 34 in the sham-control group (24 with in- and expiratory scans).
No significant differences (p-value<0.05) were found between the treatment and sham-control group for changes in CT-parameters. Furthermore, in the treatment group we only found a significant increase in air trapping due to emphysema, and in the control group only a significant decrease in airway lumen at segmental level (Table 1). However, these changes were small and not clinically relevant. No differences were found between patients who were treated in all 8 quadrants versus 7 or 6 quadrants (8 quadrants is a complete treatment). We also investigated whether there were significant associations between change in residual volume (RV), forced expiratory volume in 1 s (FEV1) or SGRQ and change in CT-parameters. In the treatment group, an improvement in general air trapping was significantly associated with an improvement in RV. Furthermore, improvements in Pi10 (the square root of wall area at airways with a perimeter of 10 mm) and airway lumen were significantly associated with an improvement in both RV and FEV1(Table 2).
Domaines
Sciences du Vivant [q-bio]
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Origine : Publication financée par une institution
Licence : CC BY - Paternité
Licence : CC BY - Paternité
