Endoscopic Retrograde Cholangiopancreatography.


Endoscopic retrograde cholangiopancreatography (ERCP) is used both in the diagnosis and treatment of many pancreatic and biliary diseases. It was first used in the 1970s at which point its main use was in diagnosis. Now, its use is mostly as a therapeutic tool.

It provides detailed and accurate information of the pancreaticobiliary system in cases which cannot be diagnosed by endoscopic ultrasound. It also provides a less invasive option than open surgery for the management of several pancreatic conditions.

Indications[1]

  • Choledocholithiasis (eg, gallstones in the common bile duct (CBD) and microlithiasis).
  • Acute pancreatitis due to biliary obstruction, sphincter of Oddi dysfunction or idiopathic, recurrent cases.
  • Detection of pancreatic divisum (more common in patients who develop pancreatitis but may not necessarily be causal).[2]
  • Diagnosis of pancreatic and biliary malignancy. Endoscopic ultrasound provides an acceptable option in many cases and can be used as a triage procedure to determine which patients should proceed to ERCP (see below).[3]
  • Palliative therapy for inoperable pancreaticobiliary malignancies – eg, drainage procedures.
  • Dilatation of benign strictures – eg, following orthoptic liver transplantation.[4]
  • Chronic pancreatitis – very controversial but there may be a role for dilatation of strictures or stent insertion.[5]
  • Manometry measures in sphincter of Oddi dysfunction.

ERCP and choledocholithiasis[6]

One method for determining who should have an ERCP is to classify patients into low-risk, intermediate-risk or high-risk.

  • Low-risk patients should proceed to laparoscopic cholecystectomy without further intervention or imaging procedures.
  • Intermediate-risk patients include those with features, such as previous history ofcholangitis or pancreatitis, slightly abnormal LFTs (eg, raised ALP but less than twice normal), dilated CBD between 8-10 mm. This group of patients should have further tests (eg, endoscopic ultrasound) before deciding on further intervention.
  • High-risk patients include those with recent cholangitis, recent acute pancreatitis,jaundice, abnormal LFTs (ALP more than twice normal) and dilated CBD >10 mm. This group will benefit most from ERCP. However, even a third of these patients will fail to have a stone on ERCP and further investigation may be needed.

ERCP and acute pancreatitis[1]

  • Acute pancreatitis with evidence of biliary tract obstruction should have urgent ERCP.
  • At ERCP, sphincterotomy may be performed to remove duct obstruction – eg, gallstone.
  • However, there is a risk that pancreatitis may be worsened.
  • A meta-analysis of studies looking at the role of ERCP in acute biliary pancreatitis has confirmed that early ERCP reduces both complications and mortality rates.[7]
  • Sphincter of Oddi dysfunction can lead to pancreatitis, usually in women following cholecystectomy, and responds to isolated biliary sphincterotomy.
  • ERCP is performed on an outpatient or inpatient basis.
  • Patients have to fast overnight.
  • Patients are usually sedated for the procedure (eg, using midazolam) and analgesia is also given.
  • Patients usually lie on their left side.
  • The back of throat is sprayed with a local anaesthetic.
  • The endoscope is passed down through to the stomach and then to the duodenum (where the ducts of the pancreaticobiliary system open, called Vater’s ampulla).
  • Air may be pumped into the duodenum to allow better visualisation.
  • Using a wire passed through the endoscope, contrast is injected through Vater’s ampulla and X-rays obtained.
  • These images will indicate areas of obstruction.
  • Further intervention can be performed down the endoscope if necessary – eg, stone removal, stent insertion, biopsies.
  • Pancreatitis – 2-9% of patients will develop pancreatitis and it is seen especially in endoscopic sphincterotomy for sphincter of Oddi dysfunction.[7][8] The majority of cases are mild but 10% of cases are moderate-to-severe and may lead to multi-organ failure and even death. The chances of pancreatitis post-ERCP can be reduced by avoiding excessive cannulation trauma and stent insertion – the latter being the most effective method.[9] Stent insertion allows pancreatic secretions to pass freely.
  • There is evidence that peri-operative indometacin or diclofenac helps to reduce the incidence of pancreatitis.[10]
  • Infection may occur – although rates are low.
  • Bleeding may occur – although severe haemorrhage is rare.
  • Perforation of the duodenum with development of an acute abdomen.
  • Failure of gallstone retrieval – may need to revert to open or more invasive procedures.
  • Prolonged pancreatic stenting is associated with stent occlusion, pancreatic duct obstruction and pseudocyst formation.
Is ERCP being superseded by endoscopic ultrasound (EUS) and magnetic resonance cholangiopancreatography (MRCP)?

  • EUS is ultrasonography via an endoscope. It is used in many pancreatic and biliary disorders, especially choledocholithiasis and pancreatic lesions – eg, neoplasms or cysts.
    • It was originally used solely for imaging purposes but, with improved techniques, it can now be combined with fine-needle aspiration (FNA).
    • Some interventional techniques can also be performed with EUS – eg, injection of bupivacaine into the coeliac ganglia for analgesia in irresectable pancreatic carcinoma.
    • EUS has a greater specificity than MRCP in detecting gallstones in the ducts (sensitivity is the same) – however, some stones can be missed by EUS.[6]
    • In pancreatitis, EUS will provide additional features (eg, peripancreatic collections) and it is also more informative in chronic pancreatitis, especially when abdominal CT and ultrasound scanning fail to find an underlying cause.
  • MRCP, on the other hand, uses selective magnetic resonance imaging to look at the biliary and pancreatic tree in greater detail and is used to diagnose disease in the pancreaticobiliary region; it does not offer any therapeutic options.
    • MRCP, due to its non-invasive nature, does not have the same mortality or morbidity rates as ERCP.
    • The main downside is that some patients will need to go on and have an ERCP anyway.
    • MRCP is, by and large, comparable to ERCP for diagnostic purposes, especially in choledocholithiasis. However, its sensitivity might decrease in the evaluation of microlithiasis. One study found that EUS allowed the diagnosis of lithiasis in approximately one third of patients with intermediate suspicion of choledocholithiasis and normal MRCP.[11]
    • MRCP is reportedly as sensitive as ERCP in detecting pancreatic cancers and unlike conventional ERCP, does not require the use of contrast material, lessening the chance of complications.[12]

In summary, ERCP has its role to play in pancreaticobiliary disorders. These are mainly therapeutic in nature. However, in cases where there is doubt regarding the diagnosis or presence of biliary obstruction, further imaging should be performed first. This may include MRCP if biliary obstruction alone is suspected or EUS in other conditions.

Further reading & references

  1. Bahr MH, Davis BR, Vitale GC; Endoscopic management of acute pancreatitis. Surg Clin North Am. 2013 Jun;93(3):563-84. doi: 10.1016/j.suc.2013.02.009. Epub 2013 Apr 13.
  2. Rustagi T, Golioto M; Diagnosis and therapy of pancreas divisum by ERCP: a single center experience. J Dig Dis. 2013 Feb;14(2):93-9. doi: 10.1111/1751-2980.12004.
  3. Zaheer A, Anwar MM, Donohoe C, et al; The diagnostic accuracy of endoscopic ultrasound in suspected biliary obstruction and its impact on endoscopic retrograde cholangiopancreatography burden in real clinical practice: a consecutive analysis. Eur J Gastroenterol Hepatol. 2013 Jul;25(7):850-7. doi: 10.1097/MEG.0b013e32835ee5d0.
  4. Wadhawan M, Kumar A, Gupta S, et al; Post-transplant biliary complications: An analysis from a predominantly living donor liver transplant center. J Gastroenterol Hepatol. 2013 Jun;28(6):1056-60. doi: 10.1111/jgh.12169.
  5. Oza VM, Kahaleh M; Endoscopic management of chronic pancreatitis. World J Gastrointest Endosc. 2013 Jan 16;5(1):19-28. doi: 10.4253/wjge.v5.i1.19.
  6. Mesenas SJ; Does the advent of endoscopic ultrasound (EUS) sound the death knell for endoscopic retrograde cholangiopancreatography (ERCP)? Ann Acad Med Singapore. 2006 Feb;35(2):89-95.
  7. Cherian JV, Selvaraj JV, Natrayan R, et al; ERCP in acute pancreatitis. Hepatobiliary Pancreat Dis Int. 2007 Jun;6(3):233-40.
  8. Abdel Aziz AM, Lehman GA; Pancreatitis after endoscopic retrograde cholangio-pancreatography. World J Gastroenterol. 2007 May 21;13(19):2655-68.
  9. Andriulli A, Forlano R, Napolitano G, et al; Pancreatic duct stents in the prophylaxis of pancreatic damage after endoscopic retrograde cholangiopancreatography: a systematic analysis of benefits and associated risks. Digestion. 2007;75(2-3):156-63. Epub 2007 Aug 6.
  10. Cheon YK; Can postendoscopic retrograde cholangiopancreatography pancreatitis be prevented by a pharmacological approach? Korean J Intern Med. 2013 Mar;28(2):141-8. doi: 10.3904/kjim.2013.28.2.141. Epub 2013 Feb 27.
  11. Vazquez-Sequeiros E, Gonzalez-Panizo Tamargo F, Boixeda-Miquel D, et al; Diagnostic accuracy and therapeutic impact of endoscopic ultrasonography in patients with intermediate suspicion of choledocholithiasis and absence of findings in magnetic resonance cholangiography. Rev Esp Enferm Dig. 2011 Sep;103(9):464-71.
  12. Moon SH, Kim MH; Prophecy about post-endoscopic retrograde cholangiopancreatography pancreatitis: from divination to science. World J Gastroenterol. 2013 Feb 7;19(5):631-7. doi: 10.3748/wjg.v19.i5.631.

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