Background: Investigating disease mechanisms and treatment responses in obstructive airway diseases with invasive sampling is hampered by the small size and mechanical artefacts that conventional forceps biopsies suffer from. Endoscopic cryobiopsies are larger and more intact and are being increasingly used. However, the technique has not yet been explored for obtaining mucosa biopsies.

Objective: To investigate differences in size and quality of endobronchial mucosal biopsies obtained with cryotechnique and forceps. Further, to check for eligibility of cryobiopsies to be evaluated with immunohistochemistry and in situ hybridization and to investigate tolerability and safety of the technique.

Methods: Endobronchial mucosal biopsies were obtained with cryotechnique and forceps from patients with haemoptysis undergoing bronchoscopy and evaluated by quantitative morphometry, automated immunohistochemistry and in situ hybridization.

Results: A total of 40 biopsies were obtained from 10 patients. Cross-sectional areas were three-fold larger in cryobiopsies (median: 3.08mm2 (IQR: 1.79) vs. 1.03mm2 (IQR: 1.10), P<0.001). Stretches of intact epithelium were 8-fold longer (median: 4.61mm (IQR: 4.50) vs. 0.55mm (IQR: 1.23), P=0.001). Content of glands (median: 0.095mm2 (IQR: 0.30) vs. 0.00mm2 (IQR: 0.01), P=0.002) and airway smooth muscle (median: 0.25mm2 (IQR: 0.30) vs. 0.060mm2 (IQR: 0.11), P=0.02) was higher in the cryobiopsies compared with forceps biopsies. Further, the cryobiopsies had well-preserved protein antigens and mRNA. Mild to moderate bleeding was the only complication observed.

Conclusion and clinical relevance: By yielding significantly larger and more intact biopsies, the cryotechnique represents a valuable new research tool to explore the bronchi in airway disease. Ultimately with the potential to create better understanding of underlying disease mechanisms and improvement of treatments. This article is protected by copyright. All rights reserved.