Complications after ERCP for malignant biliary obstruction remain an important determinant of safety and procedural quality. This study assessed the incidence, spectrum, and predictors of post-ERCP adverse events using universally available clinical and procedural variables.

All ERCPs for malignant biliary strictures (2017–2023) were retrospectively reviewed. Adverse events were defined according to ESGE criteria (pancreatitis, bleeding, perforation, cholangitis). Candidate predictors included sphincterotomy, papillary morphology, intrahepatic duct dilatation, completeness of cholangiogram, and procedural success. Associations were evaluated using univariate and multivariable logistic regression.

Among 510 patients (mean age 66 ± 13 years; 51% male), overall complication rate was 9.8%. Pancreatitis was most frequent (5.6%), followed by bleeding (2.5%), cholangitis (1.3%), and perforation (0.4%). Minimal functional sphincterotomy showed a higher pancreatitis rate numerically (7.4% vs 4.1%) but without statistical significance. Abnormal papillary anatomy doubled overall complication risk (10.8% vs 4.2%, p = 0.02). Absence of intrahepatic duct dilatation and incomplete cholangiogram were also associated with increased complications (14.3% vs 7.5%, p = 0.03). On multivariable analysis, non-dilated ducts (adjusted OR 2.9, 95% CI 1.1–7.6) remained the only independent predictor. No procedure-related mortality occurred.

Post-ERCP complications in malignant strictures follow reproducible patterns rather than patient fragility. Papillary anatomy, ductal architecture, and opacification strategy—not the underlying malignancy—drive risk. Identifying non-dilated ducts and avoiding excessive contrast injection are key to improving safety. Tailored technique and anticipatory strategy align directly with ESGE quality principles and enhance the safety of malignant biliary drainage in routine practice.