Aims: Current endoscopic ultrasound (EUS) is suboptimal in the assessment of pancreatic cystic lesions (PCLs). We developed a new through-the needle loop device, to improve the cellular yield, and thereby sensitivity, of EUS fine needle aspiration (EUS-FNA) of pancreatic cysts.

In this in-vivo animal randomized controlled trial (RCT), we aim to test the cell yield and safety profile of this through the needle loop device using artificial cysts, comparing it with the standard procedure, EUS-FNA.

Methods: This was an in-vivo randomized controlled trial in pigs using artificial cysts. In one group, the new device was deployed through a 22G EUS-FNA needle into the cysts. In the control group, cystic punction was performed with standard EUS-FNA. New devices were visually inspected post-procedure. Cytological assessment, cell counting, and hemoglobin analysis were performed in samples from both groups.

Results: Artificial cysts (n=114) were punctured in six pigs, 57 in each group. Neither adverse events nor significant device malfunction occurred during brushing with the new loop device. Samples collected with the loop had non-detectable concentrations of hemoglobin in 72% (41/57) of cases, and 26% (16/57) had less than 0.6 g/dL, with no significant difference to the controls (p=0.32). There was significantly increased cell counts with the new device (11.7×median difference, p<.0001). Cytological smears were diagnostic in 77% of cases in the device group, while 54% in the control group (p=0.01, Fisher’s exact test; p=0.006, Chi-square test).

Conclusions: This novel loop device appears to be safe, causing neither significant bleeding nor device malfunction. Samples obtained with the loop brush were suitable for cytological analysis and showed significantly higher cell yield than controls. Further clinical studies are warranted.