Randomized Trial of Endoscopist-Controlled vs. Assistant-Controlled Wire-Guided Cannulation of the Bile Duct

OBJECTIVES: Biliary cannulation is frequently the most difficult component of endoscopic retrograde cholangiopancreatography (ERCP). Techniques employed to improve safety and efficacy include wire-guided access and the use of sphincterotomes. However, a variety of options for these techniques are available and optimum strategies are not defined. We assessed whether the use of endoscopist-vs. assistant-controlled wire guidance and small vs. standard-diameter sphincterotomes improves safety and/or efficacy of bile duct cannulation. METHODS: Patients were randomized using a 2x2 factorial design to initial cannulation attempt with endoscopist-vs. assistant-controlled wire systems (1: 1 ratio) and small (3.9Fr tip) vs. standard (4.4Fr tip) sphincterotomes (1: 1 ratio). The primary efficacy outcome was successful deep bile duct cannulation within 8 attempts. Sample size of 498 was planned to demonstrate a significant increase in cannulation of 10%. Interim analysis was planned after 200 patients-with a stopping rule pre-defined for a significant difference in the composite safety end point (pancreatitis, cholangitis, bleeding, and perforation). RESULTS: The study was stopped after the interim analysis, with 216 patients randomized, due to a significant difference in the safety end point with endoscopist-vs. assistant-controlled wire guidance (3/109 (2.8%) vs. 12/107 (11.2%), P=0.016), primarily due to a lower rate of post-ERCP pancreatitis (3/109 (2.8%) vs. 10/107 (9.3%), P=0.049). The difference in successful biliary cannulation for endoscopist-vs. assistant-controlled wire guidance was -0.5% (95% CI-12.0 to 11.1%) and for small vs. standard sphincerotome -0.9% (95% CI-12.5 to 10.6%). CONCLUSIONS: Use of the endoscopist-rather than assistant-controlled wire guidance for bile duct cannulation reduces complications of ERCP such as pancreatitis.