Difficult biliary cannulation in patients with distal malignant biliary obstruction: An underestimated problem?

Background: Failed biliary cannulation still poses a major challenge in patients undergoing Endoscopic Retrograde Cholangiopancreatography (ERCP). To date, there is a lack of data on rates of Difficult Biliary Cannulation (DBC) in patients with distal malignant biliary obstruction (DMBO). Materials: This was a retrospective study (09/2015 to 02/2019) of consecutive patients with DMBO that underwent ERCP in four Italian centers. The primary outcome was to evaluate the rate of DBC. Secondary outcomes were: cannulation failure, rate of adverse events (AEs), the predictive factors for DBC as well as for AEs. Results: A total of 622 patients with DMBO, were included in the study, with 351(56,4%) matching the definition of DBC. One-hundred and two ERCP-related AEs occurred in 97 of 622 patients (15,6%). Subjects with DBC showed a higher risk for AEs (p = 0.02). The lack of pancreatitis prophylaxis (p = 0.03), diagnosis of cholangiocarcinoma (p = 0.02), the use of papillotomy (OR=1.98; 95%CI = 1.14–3.45) and the combination of two or more techniques for cannulation (OR = 2.88; 95%CI = 1.04–7.97) were associated with the occurrence of AEs. Conclusions: According to the results of this study, patients with DMBO carries a higher rate of DBC thus requiring alternative techniques for biliary drainage. Furthermore, DBC carries a high risk for AEs. Further prospective multicentric studies are needed to confirm these data in this specific subgroup of patients.