The Benign Liver EUS Optimal Core Study (BLOCs): A Prospective Randomized Multicenter Study Evaluating Wet-suction Versus Slow Pull Technique for EUS-guided Liver Biopsy.

Background and aims: The specimen quality of endoscopic ultrasound-guided liver biopsy (EUS-LB) for benign liver disease evaluation depends on the technique and type of needle used. Using a 19-gauge (19 g) fine needle biopsy (FNB) needle with 3 actuations and wet suction (WS) or slow stylet pull is the current preferred practice. We conducted a randomized prospective multicenter trial to compare wet suction (WS) to slow stylet pull (SP) technique to compare histologic yields, length of procedure, and adverse events (AE).

Methods: This prospective randomized trial (NCT03245580) included patients undergoing EUS-LB for parenchymal biopsy at 6 centers in the United States in 2020-2021. A 19 g Franseen tip EUS needle was used for all procedures. For WS, the needle was flushed with saline, and a 20 ml suction syringe with 3 to 5 ml of fluid was used. For SP, a slow pullback of stylet was used. Pathologist was blinded for tissue interpretation.

Results: One hundred fifty-three patients across 6 tertiary centers were included, with 75 patients in the WS arm and 78 patients in the SP arm. Histologic outcomes were superior in WS compared with SP [aggregate specimen length (46.5 vs. 34.5 mm, P<0.001), length of longest fragment (14 vs. 11 mm, P<0.001), and number of complete portal tracts (16 vs. 11.5, P<0.001)]. The overall ability to make a histological diagnosis was higher in WS (99% vs. 92%). Procedure length and AE did not differ between groups.

Conclusions: The use of WS compared with SP for EUS-LB resulted in superior specimen yields. Total procedure time and adverse events were similar for both techniques.