Cryobiopsy With Radial UltraSound Guidance (CYRUS): A Pilot Randomized Controlled Study

Major airway bleeding is the most feared complication of transbronchial cryobiopsy (TBC). Radial endobronchial ultrasound (REBUS) has been used to assess the peripheral lung, primarily to identify pulmonary nodules, and also peripheral blood vessels. Using REBUS-guided TBC to avoid peripheral vasculature might reduce bleeding risk. This prospective randomized double-blind pilot trial was designed to investigate the feasibility of study procedures and inform the power calculation and clinical significance of a future large randomized trial.

Consecutive TBCs were randomized to be performed with or without REBUS guidance in the same patient. A nonblinded operator obtained each biopsy while a blinded second operator managed the bleeding after each biopsy and determined when hemostasis had been obtained. Feasibility of study procedures and the ability to recruit patients were of primary interest. Time to hemostasis after each biopsy was also examined.

Forty TBCs were performed in 10 patients (4 biopsies per patient) over an enrollment period of 6 months. The time to control bleeding between biopsies was not statistically different between intervention and control arms [-14.3 (-120.1 to 92.0) s, P=0.7878]. Mean bleeding time was 139.4±59.895 seconds (REBUS 132.25± 89.305 s, non-REBUS 146.55±82.043 s). A trend towards the decreased grade of bleeding and less need for additional interventions was observed with REBUS use, but this difference did not reach statistical significance in this pilot investigation.

Our findings suggest that REBUS-guided TBC is feasible. We did not observe any statistically significant difference in time to hemostasis or bleeding grade in this pilot study.