Low bleeding rates following transbronchial lung cryobiopsy in unclassifiable interstitial lung disease

Background and objective: Bronchoscopic transbronchial lung cryobiopsy (TBLC) is a guideline-endorsed alternative to surgical lung biopsy for tissue diagnosis in unclassifiable interstitial lung disease (ILD). The reported incidence of post-procedural bleeding has varied widely. We aimed to characterize the incidence, severity and risk factors for clinically significant bleeding following TBLC using an expert-consensus airway bleeding scale, in addition to other complications and diagnostic yield.

Methods: A retrospective cohort study of consecutive adult outpatients with unclassifiable ILD who underwent TBLC following multidisciplinary discussion at a single centre in the UK between July 2016 and December 2021. TBLC was performed under general anaesthesia with fluoroscopic guidance and a prophylactic endobronchial balloon.

Results: One hundred twenty-six patients underwent TBLC (68.3% male; mean age 62.7 years; FVC 86.2%; DLCO 54.5%). Significant bleeding requiring balloon blocker reinflation for >20 min, admission to ICU, packed red blood cell transfusion, bronchial artery embolization, resuscitation or procedural abandonment, occurred in 10 cases (7.9%). Significant bleeding was associated with traction bronchiectasis on HRCT (OR 7.1, CI 1.1-59.1, p = 0.042), a TBLC histological pattern of UIP (OR 4.0, CI 1.1-14, p = 0.046) and the presence of medium-large vessels on histology (OR 37.3, CI 6.5-212, p < 0.001). BMI ≥30 (p = 0.017) and traction bronchiectasis on HRCT (p = 0.025) were significant multivariate predictors of longer total bleeding time (p = 0.017). Pneumothorax occurred in nine cases (7.1%) and the 30-day mortality was 0%. Diagnostic yield was 80.6%.

Conclusion: TBLC has an acceptable safety profile in experienced hands. Radiological traction bronchiectasis and obesity increase the risk of significant bleeding following TBLC.