Lung allograft transbronchial cryobiopsy for critical ventilated patients: a randomised trial

Background Transbronchial lung cryobiopsy is an emerging technique for diagnosing pulmonary rejection. However, no prospective studies of this procedure for critically ill lung transplant recipients who require mechanical ventilation in the intensive care unit (ICU) have been performed. Methods From March 2017 to January 2020, we performed a prospective, randomised, comparative study to assess the diagnostic yield, histological quality and safety of transbronchial lung biopsy using biopsy forceps, a 1.9-mm cryoprobe or a 2.4-mm cryoprobe. Results 89 out of 129 consecutive transbronchial biopsy procedures (forceps group, 28 procedures; 1.9-mm cryoprobe group, 31 procedures; 2.4-mm cryoprobe group, 30 procedures) were randomised. Compared with lung samples from the forceps and 1.9-mm cryoprobe groups, lung samples from the 2.4-mm cryoprobe group allowed the most definitive diagnoses (p<0.01 and p=0.02, respectively), the most diagnoses of acute lung rejection (p<0.01 and p=0.01, respectively) and the most diagnoses of rejection severity (p<0.01 and p<0.01, respectively). These samples were larger (p<0.01 and p=0.04, respectively), had the most adequate alveolar tissue (p<0.01 and p=0.02, respectively), had more vessels per procedure (p<0.01 and p=0.01, respectively) and had no significant crush artefacts. Moderate bleeding was observed in 23% of cases (p=0.01 and p=0.08, respectively). No severe bleeding was observed. Conclusions Transbronchial lung biopsy using a 2.4-mm cryoprobe allows the safe collection of lung tissue samples from critically ill lung transplant recipients who require mechanical ventilation in the ICU and has good diagnostic performance.