Abstract
Background: Bronchial Thermoplasty (BT) reduces exacerbations and improves asthma quality of life questionnaire (AQLQ) scores in asthma [1]. Studies have shown reductions in airway smooth muscle (ASM) mass and reticular basement membrane (RBM) thickness after BT, but are limited by small sample size.
Aims: To investigate airway remodeling responses to BT, and compare these to clinical outcomes.
Methods: Pre- and post-BT data was pooled for 99 patients at 7 centres. ASM mass and RBM thickness were measured on bronchial biopsies, and compared to clinical outcomes.
Results: Mean (SD) age was 48.4 years (11.7) and BMI was 29.0 kg/m2 (6.4). Baseline FEV1 was 68.8% predicted (23.1) and blood eosinophils were 0.25x10-9/L (0.26). 59 of 99 patients were taking maintenance oral Prednisolone (mean dose 25.7mg). In response to BT, mean (SD) annual exacerbation rate decreased from 6.4 (5.5) to 1.1 (1.7) (p=<0.0001). AQLQ improved from 3.2 (1.6) to 4.4 (1.7) (p=<0.0001). Lung function did not change. ASM mass (n=99) reduced from 16.1% (6.5) to 4.4% (4.1) within 6 weeks and remained reduced beyond 1 year (p=<0.0001). RBM thickness (n=35) reduced from 6.8µm (1.8) to 5.8µm (3.0) within 6 weeks and remained reduced beyond 1 year (p=0.024). No relationships were found between improvements in ASM and RBM, and clinical parameters including exacerbation rate, AQLQ, and lung function.
Conclusion: ASM mass and RBM thickness reduce rapidly following BT, and effects persist beyond 1 year. The observed improvements in airway remodeling parameters are not related to improvements in clinical outcomes. Other bronchial mucosal changes or mechanisms may play a role in the clinical response to BT.
Reference:
1) Castro et al, AJRCCM. 2010;181(2):116-24
Footnotes
Cite this article as: European Respiratory Journal 2019; 54: Suppl. 63, PA3718.
This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).
- Copyright ©the authors 2019