The risk of post-ERCP pancreatitis and the protective effect of rectal indomethacin in cases of attempted but unsuccessful prophylactic pancreatic stent placement

Background: It is believed, based on limited observational data, that an unsuccessful attempt to place a prophylactic pancreatic stent substantially increases the risk of post-ERCP pancreatitis (PEP). Objective: To better understand the risk of PEP in patients with failed pancreatic stent placement (FPS) and the impact of rectal indomethacin on this risk. Design: Secondary analysis of randomized, controlled trial data. Setting: University of Michigan and Indiana University. Patients: A total of 577 clinical trial participants at elevated risk for PEP. Interventions: Pancreatic stent placement. Main Outcome Measurements: Within the placebo group, we compared PEP rates in patients with FPS, patients who underwent successful stent placement, and in those without a stent attempt. We also performed a regression analysis evaluating the association between FPS and PEP. To define the protective effect of indomethacin, we repeated these analyses in the indomethacin group and in the full study cohort. Results: The incidence of PEP among patients in the placebo group who experienced FPS was 34.7%, significantly exceeding rates in patients who underwent successful stent placement (16.4%) and in those without a stent attempt (12.1%). After we adjusted for known PEP risk factors, FPS was found to be independently associated with PEP. Among the indomethacin group and in the full cohort, FPS was not associated with a higher risk of PEP. Limitations: Low event rate, FPS not prospectively captured. Conclusion: FPS appears to confer an increased risk of PEP, which is attenuated by rectal indomethacin administration. These findings highlight the importance of adequate training and proficiency before endoscopists attempt pancreatic stent placement and the routine use of rectal indomethacin in high-risk ERCP cases.