CONTEXT - Transbronchial cryobiopsy technique yields larger biopsies with enhanced quality. The benefits and safety of cryobiopsies have not been thoroughly studied in lung allografts.
OBJECTIVE - To compare size, quality, reproducibility of interpretation of rejection and complications of cryobiopsies with those of conventional biopsies from lung allografts.
DESIGN - All cryobiopsies (March 2014-January 2015) of lung allografts performed at Mayo Clinic, Rochester, and medical records were reviewed. For comparison, conventional biopsies from the same patient or, if unavailable, from a random patient, were selected. Two pathologists blinded to outcome reviewed all biopsies. Specimen volume, number of alveoli, small airways, and pulmonary vessels were counted and statistically compared.
RESULTS - Fifty-four biopsies (27 cryobiopsies) from 18 patients (11 men) were reviewed. A median of 3 (range, 2-5) and 10 (range, 6-12) specimens were obtained with cryobiopsies and conventional biopsies, respectively. Cryobiopsies were larger and contained more alveoli (P < .001, both) and small airways (P = .04). Conventional biopsies showed more fresh alveolar hemorrhage (procedural) and crush artifact/atelectasis (P < .001, both). Cryobiopsies contained more pulmonary veins and venules (P < .001). There was no significant difference between the types of biopsies with respect to the reviewers' agreement on grades of rejection. Complications were more frequent in the cryobiopsy group, though the difference was not statistically significant.
CONCLUSIONS - Cryobiopsies of lung allografts are larger and have less artifact. However, complications occur and should be considered. Three cryobiopsy specimens appear sufficient for histopathologic evaluation of lung allografts.