The application of transbronchial cryobiopsy in interstitial lung disease: a prospective, multicenter, real-world study

Background: Transbronchial cryobiopsy (TBCB) has been widely used to diagnose interstitial lung disease (ILD). Existing reports on TBCB in ILD are mostly single-center prospective or retrospective studies but rarely multicenter prospective real-world studies. We explored the diagnostic efficiency and safety of TBCB in ILD in a real world setting. Methods: A prospective, multicenter, real-world study was conducted to analyze the data of patients with unclarified ILD who underwent TBCB in 20 hospitals in China from October 2018 to October 2019. The results of the pathological and multidisciplinary discussion (MDD) diagnosis and complications related to TBCB were then analyzed. Results: A total of 373 patients were enrolled in this study, including 194 males and 179 females, with an average age of 52.6 +/- 12.4 years. None of the patients had severe hemorrhaging, and the incidence of pneumothorax was 4.8%. The proportions of definitive, possible, and unclassified pathological diagnoses were 62.5%, 5.6%, and 31.9%, respectively. The overall diagnostic yield of MDD was 63.5%. There were 237 patients with a definitive diagnosis of MDD and 136 patients with an unclarified MDD diagnosis. The cooling gas pressure, freezing durations, number of specimens, maximum lengths of specimens, and specimen sizes varied significantly between the definitive and unclarified MDD diagnoses. Conclusions: In China, the application of TBCB in ILD is generally safe, and its diagnostic efficiency is acceptable. Using a 1.9-mm cryoprobe to collect five samples would achieve a better positive diagnostic rate for TBCB in ILD, without a significant increase in complication risk.