Transbronchial forceps- and cryobiopsy for detecting acute cellular rejection in lung transplant recipients: A randomised trial

Transbronchial lung biopsy is routinely employed to identify acute cellular rejection (ACR) in lung transplant recipients (LTRs). This trial evaluates the clinical value of forceps and cryobiopsies and assesses the potential of cryobiopsies as a standalone histological diagnostic tool. In this open-label, randomised trial, LTRs undergoing surveillance bronchoscopy (analgosedation + intubation) 2, 4, 6, and 12 months after transplantation were included. Participants were randomly assigned (1:1) to receive either two cryobiopsies with a 2.4 mm probe alone (freezing time 3-4 seconds) or a combined five transbronchial forceps- and two cryobiopsies (combined group). The primary outcome was the diagnostic yield (suitability to detect ACR). Between July, 2021, and January, 2024, 79 LTRs were randomly assigned to the cryobiopsy-only group (n=37) or the combined group (n=41) with 82 and 80 procedures, respectively. The diagnostic yield in the cryobiopsy-only group was similar to the combined group for ACR (98.6% vs 97.3%, p=0.568). In intraindividual analyses of the combined group, cryobiopsies demonstrated a higher diagnostic yield than forceps biopsies (97.3% vs 18.7%, p=0.003), and the incidence of ACR was higher for cryobiopsies (RR 4.7 [95%CI 2.9-7.3], p<0.001). The incidence of adverse events did not differ between groups (60.9% vs 57.5%, p=0.655). The pneumothorax rate was 1.2%; no deaths or severe bleedings were observed. Transbronchial cryobiopsies are more effective than forceps biopsies in detecting ACR among LTRs. Cryobiopsies, which are safe to perform, can be used as the primary and standalone diagnostic tool for histological assessment of ACR.