Learning Curve Analysis and Predictors of Technical Failure of EUS-Guided Antegrade Stent Placement in Malignant...

Endoscopic ultrasound antegrade stent placement (EUS-AG) is a technically challenging transpapillary technique of biliary drainage. We aimed to identify the learning curve for achieving proficiency and the factors associated with technical failure of EUS-AG.

Retrospective review of patients who underwent EUS-AG at a referral cancer center was done from January 2021 till August 2024. Primary outcome was learning curve to achieve proficiency for time, technical success, and adverse events. Linear, quadratic, and cubic regression were used to assess learning curve, with time being the dependent variable. CUSUM curve analysis and 10-case moving average were also used for learning curve.

One-hundred and fifty-one patients were included in the analysis (mean age 54.15 years, 56.3% males, 27.8% cholangitis, distal block 64.2%). EUS-AG was done predominantly in view of inaccessible papilla secondary to gastroduodenal stenosis (79.5%). Technical success was achieved in 138 (91.4%) patients. Mean procedure time was 46.15 ± 24.35 min. The cubic regression model best represents the learning curve (R² 0.99) indicating plateauing after 45 procedures, suggesting proficiency and mastery after 110 procedures with secondary decrease in procedure time. The CUSUM curve shows plateauing between 37 and 56 procedures, while the 10-case moving average reaches overall mean at 43 procedures. Higher prestenotic bile duct diameter (0.003 [OR 0.790; 95% CI 0.675-0.925]) was associated with a higher chance of technical failure on univariate and multivariate analysis.

Proficiency for EUS-AG is achieved after 40-45 procedures. Caution should be exercised in those with higher prestenotic bile duct diameter considering chances of technical failure.