Moderate and Severe Post ERCP Pancreatitis; Despite Prophylactic Pancreatic Stent Placement

Abstract

Introduction: Placement of prophylactic pancreatic stents (PP stents) is a proven method to reduce the rate and severity of post ERCP pancreatitis (PEP) in high risk settings. This study was done to determine the rate of early passage of PP stents in moderate and severe PEP. We hypothesized that stent passage by the 3rd day after placement might be premature and contribute to more frequent or severe PEP. Methods: We analyzed 27,176 ERCP procedures over 13 year period (January 1994 to September 2007) which were prospectively entered into our ERCP database. PP stents were placed in 7,661 patients. Of those, 580 patients (7.5%) developed PEP; mild 460 (6.0%), moderate 87 (1.1%) and severe 33 (0.4%). Patients who were hospitalized at our institution for moderate (59) or severe PEP (27) had abdominal X-rays reviewed for stent persistence or passage from the pancreas. Risk factors for PEP were reviewed. Results: Risk factors for developing moderate PEP were not significantly different from those with severe PEP: female (79.7% versus 92.9%), sphincter of Oddi manometry (94.9% versus 88.9%), pancreatic sphincter of Oddi dysfunction (SOD) (59.3% versus 59.3%), biliary SOD (30.5% versus 29.6%), balloon dilation (8.5% versus 14.8%), dual sphincterotomy (67.8% versus 55.6%), pancreatography including tail filling (81.0 %versus 88.9%), no chronic pancreatitis (72.4% versus 88.9%) and normal cholangiogram (78.2% versus 80.8%). Patients with moderate and severe PEP had 6.6 and 6.9 risks factors, respectively (p = NS). Stent diameter in moderate PEP were; 3 Fr, 42.4%; 4 Fr, 35.6%; > 4 Fr, 22.0%. In severe PEP, stent diameter were; 3 Fr, 51.9%; 4 Fr, 25.9%; > 4 Fr, 22.2%. Protective stents passed from the pancreatic duct by the 3rd day in 7 patients with moderate PEP (11.9%) and 5 patients with severe PEP (18.5%) (p = 0.505). Hospitalization days in patients with moderate PEP whose stent passed by and after the 3rd day were 7.43 (1.46) and 8.37 (1.16) days, respectively (p = NS). Hospitalization days in patients with severe PEP whose stent passed by and after the 3rd day were 21.60 (6.11) and 22.23 (3.13) days, respectively (p = NS). A confounding variable was the co-existence of perforation in 1 moderate and 3 severe PEP. Summary: The frequency of moderate and severe PEP in high risk patients with PP stent placement is relatively low but PEP still occurs. Our study showed that more than 80% of patients who developed moderate and severe PEP still had the PP stent in place more than 3 days. Conclusion: Early stent fall out does not appear to be a significant contributing factor for moderate and severe PEP. The optimal duration of PP stent placement is unknown.