Validation of the diagnostic yield and safety of transbronchial lung cryobiopsy in diagnosis of interstitial lung disease: a retrospective study from a single center in China

Background Interstitial lung disease (ILD) is a group of rare lung disorders affecting the lung interstitium. Surgical lung biopsy (SLB) is considered the gold standard for the diagnosis of ILDs. However, the clinical use of SLB is limited by the procedure-associated complications. Although transbronchial lung cryobiopsy (TBLC) is reported to be safer than SLB and more effective than transbronchial lung biopsy (TBLB), it has not been widely used in clinical practice due to the small sample size reported. The aim of the present study was to validate the safety and diagnostic yield of TBLC in a large Chinese cohort from a single-center in China. Methods Included in this study were ILD patients who received TBLC at Drum Tower Hospital in Nanjing, China between 2017 and 2020. The clinical features of these ILD patients were obtained from the medical records. Risk factors associated with complication occurrence during TBLC were evaluated by student's t-tests or Fisher's exact tests as appropriate. Results Included in this study were 159 ILD patients with a mean age of 48.3 ± 11.3 years. The mean procedural duration for TBLC was 27.2 ± 5.92min. The mean number of biopsied specimens was 4.3 ± 0.9 with a mean diameter of 0.29 ± 0.13 mm. The overall occurrence of pneumothorax and severe bleeding was 15.7% and 16.3% respectively. The overall histopathologic diagnostic yield was 82.2%. Biopsied in the left lung and obtaining higher number of specimens had a much higher risk of developing pneumothorax. In addition, the larger diameter of specimen and longer procedural time were significantly associated with higher risk of bleeding. Conclusion TBLC is safe for the diagnosis of ILD with a high diagnostic yield. The associated complications could be tolerated and well controlled.