Sept. 17, 2016
Endoscopic retrograde cholangiopancreatography (ERCP), which is primarily used to acquire access for pancreatic or biliary drainage, is successful in about 90 percent of patients with normal upper gastrointestinal anatomy. But the procedure often fails in patients who have altered anatomy or gastroduodenal obstruction. Traditionally, surgical and percutaneous interventions have been the only options for these patients.
Endoscopic ultrasound (EUS) was developed as a less invasive alternative to surgery and radiology and is now used in appropriate patients after failed ERCP. Since 1995, when the first endoscopic ultrasound-guided pancreatography was reported, high-volume centers with experienced endoscopists have noted technical success rates approaching 70 percent for EUS-guided pancreatic duct drainage. The rates are lower for less experienced endoscopists in low-volume centers, and the technique remains technically challenging, with a high risk of adverse events.
Michael J. Levy, M.D., a gastroenterologist specializing in endoscopic management of pancreatic and biliary disorders at Mayo Clinic's campus in Rochester, Minnesota, says EUS-guided procedures have a long learning curve and that even experts continue to learn as the techniques evolve. "Ideally, it should be performed by someone trained in both ERCP and EUS, but even then, it is one of the most challenging endoscopic procedures," he says.
At Mayo Clinic's campus in Minnesota, EUS-guided pancreatic duct drainage is not only used after failed ERCP, but is often the first intervention for patients with anastomotic stricture after pancreaticoduodenectomy because of the higher success rate for stent placement. In the largest single-center report to date, which was published in Gastrointestinal Endoscopy in 2013, Mayo clinicians described the technical and clinical success rates and long-term clinical outcomes of EUS-guided stent placement in 43 patients, 14 percent of whom had not previously undergone ERCP. Technical success was achieved in 32 of the 43 patients, 14 with retrograde and 18 with antegrade stent insertion.
Symptoms completely resolved in 83 percent of patients while stents were in place; after the stents were removed, patients were followed for an additional 32 months. Twenty-nine patients were available for long-term follow-up. Of these, nearly 70 percent had complete symptom resolution, with partial resolution in the remaining 30 percent.
Four patients developed persistent symptoms, and there were 11 failed cases overall. In one case, the endoscopist was unable to advance the guidewire into the main pancreatic duct; in others, the guidewire was lost or couldn't be advanced through the papilla or anastomosis. The authors note that the chance of technical failure was higher when ERCP and EUS were performed on the same day.
Among the failed cases, nearly half required surgery. Three patients experienced serious complications, such as acute pancreatitis and peripancreatic abscess. These and other complications including infection, bleeding and pain are relatively common and can be severe, Dr. Levy says.
Victoria Gomez, M.D., a gastroenterologist specializing in EUS, ERCP, and the endoscopic management of pancreas and biliary diseases at Mayo Clinic's campus in Jacksonville, Florida, also cautions that EUS-guided pancreatic and biliary drainage are "not benign procedures and require careful planning and discussion with patients due to the risks."
In Mayo Clinic's experience, stent dysfunction — either migration or occlusion — occurs in about 25 percent of patients. Other centers report higher numbers. Dr. Levy suggests Mayo's data may reflect routine stent removal or replacement at 90 and 46 days, respectively, noting that more data are needed to determine the best method for stent placement and the timing of stent removal. A complete discussion of ultrasound-guided pancreatic duct drainage was published in the Journal of Hepato-Biliary-Pancreatic Sciences in 2015.
The rendezvous technique
The method of stent placement depends on the expertise of the endoscopist, the type of drainage and available equipment. For main pancreatic duct drainage, antegrade placement may be preferable because it is a shorter procedure and can be performed entirely with an echoendoscope. In the retrograde, or rendezvous approach, the echoendoscope is removed and exchanged for a side-viewing duodenoscope or a forward-viewing endoscope for patients with surgically altered anatomy. After the exchange, a stent is placed retrograde from the gut lumen into the pancreatic duct via the papilla or an anastomosis.
Dr. Gomez uses the rendezvous technique for bile duct obstructions due to malignancy and occasionally for obstructions resulting from benign conditions.
"In situations where ERCP cannot be performed due to blockage or narrowing of the duodenum or if the opening of the bile duct, the ampulla, cannot be accessed, then the rendezvous procedure can be useful. This is also when knowing how to perform both EUS and ERCP can be extremely advantageous. When successful, patients can undergo complete internal drainage of the bile duct, which can improve their pain and quality of life more than the percutaneous method," she says.
Mark D. Topazian, M.D., a gastroenterologist specializing in the endoscopic management of pancreas and biliary diseases at Mayo Clinic's campus in Minnesota, says, "We now have a large experience with EUS-guided pancreatic and biliary duct access and drainage, and we have relatively few failures. But because of the difficulty of the procedure and the potential risks, it has to be performed by endoscopists trained in both ERCP and EUS who are backed by a strong multidisciplinary team."
For more information
Fujii LL, et al. EUS-guided pancreatic duct intervention: Outcomes of a single tertiary-care referral center experience. Gastrointestinal Endoscopy. 2013;78:854.
Fujii-Lau LL, et al. Endoscopic ultrasound-guided pancreatic duct drainage. Journal of Hepato-Biliary-Pancreatic Sciences. 2015;22:51.