Transbronchial lung cryobiopsy guided by radial mini-probe endobronchial ultrasound in interstitial lung diseases - a multicenter prospective study

Introduction: Transbronchial lung cryobiopsy (TBLC) is commonly used in diagnosing interstitial lung diseases (ILDs). Ageneral anesthesia with endotracheal intubation, balloon blockers and fluoroscopy control is the most common modality. Simplifying the procedure without decreasing it's safety could result in wider use. Prospective, observational study was conducted in three Polish pulmonology centers to evaluate safety and diagnostic yield of TBLC under conscious sedation, without intubation and bronchial blockers and with radial-EBUS guidance instead of fluoroscopy.

Material and methods: In patients suspected of ILD, in accordance with high resolution computer tomography (HRCT) selected lung segments were examined with radial-EBUS mini probe without aguide sheath. If the lung infiltrations were visible this locations were preferred. If not, specimens were taken from two different segments of the same lobe. Two to five biopsies with freezing time 5-8 seconds were performed. Moreover ultrasound examination was used to avoid injury of lung vessels.

Results: From March 2017 to September 2019 - 114 patients (M: 59, F: 55) of mean (SD) age 54 (14) years were included to the study on the basis of medical history and HRCT. Histopathology was conclusive in 90 (79%) patients and included 16 different diagnoses (sarcoidosis, EAA, COP predominantly). 24 inconclusive biopsies of unclassifiable pulmonary fibrosis were followed up. Complications included five cases (4.4%) of pneumothorax requiring achest tube drainage and aminor and moderate bleeding in few cases. There was no need for use of balloon bronchial blockers.

Conclusions: TBLC under conscious sedation guided by radial EBUS mini-probe is novel, reasonable and safe technique for histological diagnosis of ILDs.