The Safety and Feasibility of Radial Endobronchial Ultrasound-guided Transbronchial Cryobiopsy in Diffuse Pulmonary Infiltrate Diseases

Abstract

Background Transbronchial lung cryobiopsy (TBLC) has emerged as a new bronchoscopic procedure which can improve specimen size and obtain crush artifact-free tissue to increase diagnostic yield in various diffuse parenchymal lung diseases (DPLDs). However, TBLC has been associated with a higher incidence of complications, and variability in diagnostic yield. Radial probe endobronchial ultrasound (R-EBUS) may be able to overcome these problems. We evaluated the safety and feasibility of TBLC in combination with R-EBUS to diagnose DPLDs.Methods We conducted this retrospective study at a single medical center from January 2015 to March 2019. Patients with DPLDs who underwent R-EBUS to locate target lesions and confirm the absence of adjacent vessels, followed by sampling with conventional transbronchial lung forceps biopsy (TBLB) and cryobiopsy (TBLC) were enrolled. TBLC and TBLB samples were sent to the pathology department for diagnostic analysis. The sample size, diagnostic yield and complications after the procedure were recorded.Results A total 30 patients with DPLD were analyzed, of whom 17 had diffuse lung infiltrates and 13 had pulmonary nodules/masses. The overall diagnostic rate was 80% (24/30) and the diagnostic yield increased from 46.7% with the forceps biopsy to 73.3% after adding cryobiopsy (p=0.038). Compared to conventional transbronchial biopsy with forceps, cryobiopsy provided a larger specimen and sample volume (40 mm3 vs 6 mm3; p<0.001). Twenty-two (73.3%) patients had mild bleeding, two (6.7%) had moderate to severe bleeding, and one (3%) had pneumothorax. Ten patients who initially had non-diagnostic results by TBLB received a definite diagnosis after adding TBLC. Among these patients, eight (8/10) were ultimately diagnosed with interstitial lung disease (ILD) (p<0.001).Conclusions TBLC with R-EBUS guidance increased the diagnostic yield in patients with DPLD, particularly in those with ILD. The samples obtained by TBLC were significantly larger and there were no severe complications after the procedure. Larger studies are needed to confirm the safety and feasibility of R-EBUS-guided TBLC.