Factors Associated With Difficult Endoscopic Ultrasonography-guided Biliary Drainage.

Background and aims: When endoscopic retrograde cholangiopancreatography-guided biliary drainage is challenging, endoscopic ultrasound-guided biliary drainage (EUS-BD) can be used as an alternate treatment; however, this method requires operator expertise. Therefore, this study aimed to clarify the factors that are associated with a difficult EUS-BD.

Patients and methods: Patients who successfully underwent EUS-BD were enrolled in this study. The patients were divided into the easy group and difficult group depending on whether the procedural time was more than 60 minutes, which was the cutoff value elicited from past reports. Patient characteristics and procedural factors were compared between the two groups. The factors associated with difficult procedures were also investigated.

Results: The patient characteristics were not significantly different between the easy group (n=22) and the difficult group (n=19). The diameter of the punctured bile duct was significantly different between the two groups. In the multivariate analysis, the diameter of the punctured bile duct was the only factor associated with a difficult EUS-BD (odds ratio 0.65, 95% confidence interval 0.46-0.91, P value=0.012). The cutoff value for the diameter of the punctured bile duct in predicting a difficult EUS-BD was 7.0 mm (area under the curve: 0.83, sensitivity 84.2%, specificity 86.4%).

Conclusions: A nondilated bile duct might be a predictive factor for a difficult EUS-BD. For beginners of EUS-BD, the cutoff value for the punctured bile duct diameter found in this study, 7.0 mm, might become a barometer for puncture point selection.