Bret T. Petersen, MD, FASGE

Associate Editor



Bret T. Petersen, MD, FASGE, is Professor of Medicine in the Division of Gastroenterology and Hepatology at the Mayo Clinic in Rochester, Minnesota. His practice is focused in the Mayo Pancreas Clinic and the Advanced Endoscopy Group. His professional interests include pancreatic and biliary diseases, performance and outcomes of ERCP, and delivery of endoscopic services. At Mayo, Dr. Petersen is a past Director of Endoscopy and has served on multiple clinic and foundation committees. He has directed numerous American Society for Gastrointestinal Endoscopy (ASGE) and Mayo courses, particularly related to the performance of ERCP. He has received the Mayo Award for Excellence, GI Fellows Award for Outstanding Teacher, and Department of Medicine Laureate Award (GI), as well as the Master Endoscopist Award of the ASGE. Dr. Petersen is the incoming Secretary for (ASGE) and a past Chair of the Technology and Quality Assurance in Endoscopy committees.



Boston Scientific 

Advisory Board 

Ethicon/J & J



  • Pancreatobiliary

    Urgent Early Pancreatic Drainage Is Safe and Effective

    Bret T. Petersen, MD, FASGE reviewing Oblizacek N, et al. Gastrointest Endosc 2020 Jan 18.

    Endoscopic decompression and drainage of immature pancreatic and peripancreatic fluid collections with incomplete encapsulation by a wall of surrounding tissue have generally been avoided out of concern for widespread leakage of contents and air throughout the abdomen, potentially culminating in peritonitis or acute pneumoperitoneum. This study compared 19 cases of early intervention over 10 years of practice versus intervention in mature cases of walled-off necrosis.

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  • Pancreatobiliary

    Duodenoscope Sheath Protects High-Risk End of Instrument

    Bret T. Petersen, MD, FASGE reviewing Pasricha PJ, et al. Gastrointest Endosc 2020 Mar 6.

    The risk of transmission of microorganisms by contaminated duodenoscopes remains a pertinent concern for ERCP practices. This report describes microbial challenge studies in a single-use device, recently cleared by the Food and Drug Administration, that seals the distal end of the duodenoscope.

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  • Pancreatobiliary

    Reliable Biodegradable Pancreatic and Biliary Stents May Be on the Horizon

    Bret T. Petersen, MD, FASGE reviewing Anderloni A, et al. Gastrointest Endosc 2020 Feb 24.

    Biodegradable biliary and pancreatic stents with predictable performance would be tremendously cost-effective for many pathologies for which temporary stenting is used. In this prospective pilot study of a new helicoid stent with variable intended degradation speeds, the authors assessed stent degradation time, adverse events, technical aspects of placement, and fluoroscopic visualization.

  • Pancreatobiliary

    Helpful Perspective From Italy Regarding GI Endoscopy in Midst of COVID-19 Pandemic

    Bret T. Petersen, MD, FASGE reviewing Repici A, et al. Gastrointest Endosc 2020 Mar 14.

    Transmission of Coronavirus-Associated Disease 2019 (COVID-19) is primarily airborne and by direct contact, but virions are also present in stool and tissues. Therefore, gastrointestinal endoscopy inherently risks both exposure and transmission among patients and staff. This article presents measures implemented in a major northern Italian medical center to limit risks to patients and staff.

  • Pancreatobiliary

    Single-Use Duodenoscope Functionality Excellent in Early Studies

    Bret T. Petersen, MD, FASGE reviewing Muthusamy VR, et al. Clin Gastroenterol Hepatol 2019 Nov 6 and Ross A, et al. Gastrointest Endosc 2020 Feb.

    Two companies have developed single-use duodenoscopes as a means for avoiding potential patient-to-patient transmission of infections. This set of articles presents data from simulated evaluation in a synthetic bench model and the initial clinical experience for the first FDA-cleared instrument.

  • Pancreatobiliary

    Time Is of the Essence for Moderate to Severe Ascending Cholangitis

    Bret T. Petersen, MD, FASGE reviewing Iqbal U, et al. Gastrointest Endosc 2019 Oct 16.

    While most patients with acute cholangitis respond to initial antibiotics and hydration, definitive biliary drainage or clearance of obstruction is required to resolve the infection in about one-quarter of patients. Studies have varied as to the urgency of intervention by ERCP. The authors of this meta-analysis utilized rigorous criteria to evaluate the published literature addressing patient outcomes relative to the timing of ERCP.

  • Pancreatobiliary

    Cholangioscopy for Indeterminate Strictures: Is the Juice Worth the Squeeze? Probably

    Bret T. Petersen, MD, FASGE reviewing Gerges C, et al. Gastrointest Endosc 2019 Nov 25.

    Biliary strictures are often hard to characterize using standard brush cytology and fluoroscopically directed biopsies. Visually targeted biopsy during cholangioscopy might be superior to these standard sampling techniques. This study randomized patients with indeterminate, intrinsic, mid-to-proximal bile duct strictures, identified by MRCP, to initial assessment with a SpyGlass single-operator cholangioscopy exam and directed biopsies without use of prior cholangiography versus standard fluoroscopic imaging and brush cytology.

  • Pancreatobiliary

    Cancer in IPMN? Don’t Stop Looking!

    Bret T. Petersen, MD, FASGE reviewing Oyama H, et al. Gastroenterology 2019 Aug 29.

    Pancreatic intraductal papillary mucinous neoplasia (IPMN) lesions pose a risk for progression to malignancy and are surveyed for evidence of malignant transformation or high-risk features for evolving transformation. However, some guidelines suggest forgoing surveillance in patients with stable findings over 5 years. Here the authors report the incidences for both pancreatic carcinoma arising from IPMN lesions and typical pancreatic ductal adenocarcinoma in patients followed for branch-duct IPMN over many years.

  • Pancreatobiliary

    Uncovered Versus Covered Stents With Neoadjuvant Therapy for Pancreatic Cancer

    Bret T. Petersen, MD, FASGE reviewing Seo DW, et al. Gastrointest Endosc 2019 July 2.

    Pancreatic ductal adenocarcinoma is increasingly being treated with neoadjuvant therapy prior to definitive consideration of surgical extirpation. This trial randomized 119 patients with malignant biliary obstruction to uncovered self-expanding metal stent (SEMS) versus fully covered SEMS before or during neoadjuvant therapy and prior to planned surgery.

  • Pancreatobiliary

    Liraglutide and Cholecystitis Link – May Be Real but What Mechanism?

    Bret T. Petersen, MD, FASGE reviewing Nauck MA, et al. Diabetes Care 2019 Aug 9.

    The randomized LEADER study of the cardiovascular outcomes of liraglutide therapy in type 2 diabetes patients with high cardiovascular risks suggested higher rates of both cholelithiasis and acute gallstone disease in those on the GLP-1RA agent. This post hoc study further assessed incidence, severity, and presentations of biliary disease in this patient population.

  • Pancreatobiliary

    Dysbiosis and Altered Bile Acids: Are They Clues to Cyclic Exacerbation of Injury in PSC?

    Bret T. Petersen, MD, FASGE reviewing Liwinski T, et al. Gut 2019 June 26.

    Perturbations of the colonic microbiome are seen in a variety of gastrointestinal diseases, including primary sclerosing cholangitis (PSC). In this study, the investigators compared the oral, duodenal, and biliary microbiome and the biliary bile acid composition in patients with PSC compared to control patients.

  • Pancreatobiliary

    Stent Placement Better Than Sphincterotomy for Treatment of Postcholecystectomy Bile Leak

    Bret T. Petersen, MD, FASGE reviewing Abbas A, et al. Gastrointest Endosc 2019 Aug.

    Postcholecystectomy bile leaks are typically treated with bile duct decompression or drainage via ERCP. The authors of this study evaluated 1028 patients to characterize the timing, effectiveness, and adverse events of endoscopic intervention using sphincterotomy, biliary stent placement, or both.

  • Pancreatobiliary

    Scheduled Pursuit of Dominant Strictures in PSC May Be Beneficial

    Bret T. Petersen, MD, FASGE reviewing Rupp C, et al. Gut 2019 Mar 25.

    In this retrospective study of endoscopic therapy for primary sclerosing cholangitis, the authors evaluated the outcomes of annual endoscopic surveillance, with serial dilation of identified dominant strictures until near or total morphological resolution was demonstrated, compared with endoscopic assessment and intervention based on symptoms and labs alone.

  • Pancreatobiliary

    Look Further; SIBO May Explain Failure of Enzyme Therapy in Severe Chronic Pancreatitis

    Bret T. Petersen, MD, FASGE reviewing Lee AA, et al. Am J Gastroenterol 2019 April 16.

    Small intestinal bacterial overgrowth (SIBO) may occur in patients with chronic pancreatitis, complicating interpretation and management of overlapping symptoms. Retrospective evaluation of 5 defining variables and 41 investigational variables identified 5 variables predictive for SIBO.

  • Pancreatobiliary

    Plastic Still Works for Post-cholecystectomy Biliary Strictures but Takes Time

    Bret T. Petersen, MD, FASGE reviewing Costamagna G, et al. Gastrointest Endosc 2019 June 5.

    The authors of this study sought to evaluate the utility of therapy employing multiple plastic stents for post-cholecystectomy biliary strictures without complete transection. One hundred fifty-four patients underwent serial endoscopic retrograde cholangiopancreatographys with stent exchange and increase in number of stents every 3 to 4 months until resolution.

  • Pancreatobiliary

    Premature Closure of Laparoscopic Whipple Trial Signals Importance of Asking About Experience and Outcomes

    Bret T. Petersen, MD, FASGE reviewing van Hilst J, et al. Lancet Gastroenterol Hepatol 2019 Mar.

    Laparoscopic pancreatoduodenectomy (LPD) is increasing in frequency, yet the learning curve and potential risks versus benefits remain incompletely defined. This Dutch study evaluated the safety and time to functional recovery for LPD versus traditional open technique in patients with malignant, premalignant, or benign conditions.

  • Pancreatobiliary

    Stenting for Hilar Strictures – Stent-In-Stent and Side-By-Side Equivalent but Different

    Bret T. Petersen, MD, FASGE reviewing Lee TH, et al. Gastrointest Endosc 2019 Mar 21.

    Malignant biliary strictures at the hepatic hilum are relatively common lesions, for which endoscopic stenting is appropriate. In this study, 69 patients with confirmed, inoperable malignant hilar lesions were randomized to bilateral stent-in-stent or stent-by-stent biliary drainage to compare outcomes.

  • Pancreatobiliary

    Declining Rates of Bile Duct Injury During Laparoscopic Cholecystectomy

    Bret T. Petersen, MD, FASGE reviewing Mangieri CW, et al. Surg Endosc 2019 Mar.

    Laparoscopy is the preferred approach to cholecystectomy in most circumstances; however, the commonly quoted 0.5% rate of bile duct injury (BDI) is three-fold greater than for open cholecystectomy. This study looks at the rate of BDI in the modern era.

  • Pancreatobiliary

    Ensuring Adequate Procedure Volumes for Advanced Trainees to Reach Competence

    Bret T. Petersen, MD, FASGE reviewing Wani S, et al. Gastrointest Endosc 2019 Feb 7.

    Study authors from 32 advanced training centers prospectively evaluated 37 advanced trainees following every fifth endoscopic ultrasonography and endoscopic retrograde cholangiopancreatography examination to define the number of procedures required to reach competence by the average advanced trainee.

  • Pancreatobiliary

    Echoendoscope Cultures Reflect Persistent but Far Lower Risk Than Duodenoscopes

    Bret T. Petersen, MD, FASGE reviewing Becq A, et al. Gastrointest Endosc 2019 Jan 14.

    To assess whether echoendoscopes are at risk of infectious transmission, similar to what has been discovered in previous studies of duodenoscopes, the authors obtained cultures from the transducers, working channels, and elevators, when present, of 51 linear and 50 radial endoscopes the morning after standard reprocessing with single cycles of high-level disinfection.