Endoscopic Retrograde Cholangiopancreatography (ERCP)

Overview

Endoscopic retrograde cholangiopancreatography (ERCP) is a combined endoscopic and fluoroscopic operation in which an endoscope is advanced into the duodenum's second section, allowing additional instruments to be inserted into the biliary and pancreatic channels via the main duodenal papilla. Contrast material can be injected into these ducts, allowing for radiologic imaging and, if necessary, therapeutic intervention. ERCP began as a diagnostic operation involving cannulation of the pancreatic and biliary ducts, but it has changed over time and is now mostly utilized as a therapeutic technique.

Endoscopic Retrograde Cholangiopancreatography (ERCP) definition

Endoscopic retrograde cholangiopancreatography (ERCP) was first used to diagnose biliary and pancreatic disorders more than four decades ago. ERCP is currently utilized mostly as a therapeutic method to treat biliary or pancreatic duct blockage. These facts are significant and important, but their external validity is restricted. Implementation into ordinary practice should be weighed with the understanding that these investigations were carried out under highly specialized conditions.

Anatomy and Physiology

The major pancreatic duct joins the common bile duct and empties into the ampulla of Vater (hepato-pancreatic ampulla), which is regulated by the Oddi sphincter. The entrance of the ampulla of Vater into the second half of the duodenum is known as the major duodenal papilla. The pancreatic duct and the common bile duct may remain distinct or combine at the papilla's end, or they may create a single duct.

A typical anatomic variety known as pancreas divisum occurs in 10% of the population, where the major pancreatic duct (duct of Wirsung) and the smaller pancreatic duct (duct of Santorini) do not merge, and the minor duodenal papilla becomes the primary route for pancreatic drainage. The minor duodenal papilla is located approximately 2 cm proximal to the ampulla of Vater and may contain a sphincter known as the Helly sphincter.

ERCP Indications

Endoscopy is used in ERCP to locate the main and minor papillae. To detect the biliary and pancreatic ductal systems, cannulation is performed and contrast material is administered. Diagnostic techniques, such as cholangiopancreatoscopy, biopsy, or brush cytology, can be performed during ERCP. An intraductal ultrasound may be performed as well. Sphincterotomy, stent implantation, and stone removal are all therapeutic applications.

Obstructive jaundice, biliary or pancreatic ductal system disease treatment or tissue sampling, suspicion for pancreatic cancer, pancreatitis of unknown cause, sphincter of Oddi manometry, nasobiliary drainage, biliary stenting for strictures and leakage, drainage of pancreatic pseudocysts, and balloon dilation of the duodenal papilla and ductal strictures are all indication

Sphincterotomy is used to treat sphincter of Oddi dysfunction or stenosis, difficulties with biliary stenting or accessing the pancreatic duct, biliary strictures, bile duct stones, bile sump syndrome after choledochoduodenostomy, choledochocele, and poor surgical candidates with ampullary carcinoma.

ERCP Contraindications

Absolute contraindications for ERCP include the following:

• Patient refusal to undergo the procedure
• Unstable cardiopulmonary, neurologic, or cardiovascular status
• Existing bowel perforation

Relative contraindications for ERCP include structural problems of the esophagus, stomach, or small intestine. Conditions such as esophageal stricture, paraesophageal herniation, esophageal diverticulum, gastric volvulus, gastric outlet blockage, and small-bowel obstruction are examples of acquired conditions. A changed surgical anatomy, such as that observed following a Billroth II or Roux-en-Y jejunostomy, may also be a relative contraindication for ERCP.

Several variables influence the appropriate technique for ERCP access in individuals with changed surgical anatomy when ERCP is necessary. Long versus short Roux limb, native papilla versus bilioenteric anastomosis, previous sphincterotomy, predicted auxiliary usage (eg, sphincter of Oddi manometry), surgical risk, probability of recurrent surgeries, and potential of internal hernias are among these considerations.

Acute pancreatitis is also regarded a relative contraindication, unless the cause of the pancreatitis is gallstone-related and the treatment objective is to better the clinical outcome by stone extraction. Furthermore, in coagulopathic patients (international normalized ratio [INR] >1.5 or platelet count 50,000/L), ERCP with sphincterotomy or ampullectomy is often contraindicated.

ERCP Instruments

Because it provides a superior view of the main duodenal papilla and makes cannulation easier, the side-viewing duodenoscope is regarded the gold standard for ERCP procedures. In patients with rebuilt gastrointestinal architecture, such as those undergoing Billroth II gastrectomy or Roux-en-Y surgery, the afferent loop entry is concealed, and the afferent loop is stretched and the papillary position is inverted at a sharp angle. In these cases, the typical side-viewing endoscope has a narrow vision field and makes afferent loop insertion difficult, raising the risk of intestinal injury.

In certain cases, when afferent loop intubation is easier but papillary cannulation is more difficult, a forward-viewing endoscope may be an acceptable option. The inverted papillary orientation makes both side-viewing and forward-viewing endoscopes difficult to use. The double-balloon enteroscopy technique alternately inflates and deflates two balloons to move the forward-viewing endoscope into the gut.

The dual lumen forward-viewing endoscope would allow the use of other surgical tools such as an Allis forceps to grasp the papilla, and employing a stiffer endoscope with manual compression or devices such as a polypectomy snare to make cannulation simpler may be investigated.

Preparation of patient 

The procedure is carried out at a doctor's office, clinic, or hospital. Sedation is frequently used. You are not unconscious throughout the operation, but you are given "sedatives," which relax and make you drowsy.

ERCP may need to be performed under general anaesthetic, with you entirely sleeping. Your doctor will discuss the need for general anesthesia with you. You may require a comprehensive physical evaluation. You may also require additional tests to ensure that you are in good enough health to undergo surgery.

The surgeon who will do your ERCP will discuss the procedure's risks and advantages with you. You will then sign a document stating that you understand and consent to the procedure. Before surgery, your surgeon's office will advise you on what to do and what to avoid. Your surgeon will give you specific instructions, but here are some general guidelines.

• Before surgery, stop eating and drinking at the time your doctor specifies.
• You may take drugs prescribed by your doctor on the morning of your operation. Take these with merely a sip of water.
• Certain medications may need to be discontinued prior to surgery. These include blood thinners, vitamins, and immune-suppressing medications. When scheduling your prescriptions, consult with your surgeon.
• Inform your surgeon if you are allergic to shellfish or iodine.

You will require a ride home from the treatment. You may also require someone to accompany you overnight. Inquire with your doctor or nurse about how much assistance you may require.

ERCP Technique

Endoscopic papillectomy, sphincter of Oddi manometry, sphincterotomy, endoscopic papillary balloon dilatation, stone removal, tissue sampling, installation of biliary and pancreatic stents, cholangiopancreatoscopy, and biliary and pancreatic drainage are all techniques utilized in ERCP.

The process begins with the duodenoscope being passed through a mouthguard. The duodenoscope is subsequently moved into the duodenal bulb via the stomach pylorus. To see the main duodenal papilla, a protuberance at the confluence of the horizontal and vertical duodenal folds, the scope should be moved to the second half of the duodenum. The main duodenal papilla is then cannulated. The preferred wire-guided approach involves inserting a guidewire into the common bile duct or pancreatic duct before injecting contrast.

The typical contrast-assisted approach, on the other hand, includes injecting contrast material after inserting the cannulation device tip into the main duodenal papillary orifice to ensure appropriate alignment. Difficult cannulation might be caused by a periampullary diverticulum, an impacted biliary stone, bile duct stenosis, or a bile duct or pancreatic head tumor. In rare situations of idiopathic recurrent acute pancreatitis or pancreatic divisum, cannulation of the minor papilla with sphincterotomy may be performed.

Per-oral cholangiopancreatoscopy can be performed using a mother-baby system (dual operator), the SpyGlass approach (single operator), or direct per-oral cholangioscopy (DPOC).

The dual operator system, also known as the mother-baby system, requires two endoscopists to operate, with one endoscopist controlling the mother duodenoscope and the second endoscopist controlling the baby cholangiopancreatoscope, with a tip that is only deflectable in one plane, up and down.

The SpyGlass technology is catheter-based, with the optical probe passing via a 4-lumen catheter with a deflectable tip up-down and right-left. The cholangioscope is inserted through the 1.2 mm working channel of the therapeutic duodenoscope, across a guidewire, into the biliary duct in both the dual and single operator procedures.

Ultraslim and transnasal endoscopes with digital imaging are used by DPOC. Because their shaft diameters range from 4.9 to 5.9 mm, they are employed in situations with dilated common bile duct. In these cases, insufflation should be performed using water or carbon dioxide to avoid air embolism.

The distal diameters of cholangioscopes range from 3.1 to 3.5 mm. The operating lengths of ERCPs range from 187 to 220 cm. Ultraslim endoscopes offer a wide range of angulation, a working length of 65 to 110 cm, and a working channel diameter of 2 to 2.2 mm, allowing for cholangioscopy accessories such as biopsy forceps, electrohydraulic lithotripsy, and laser lithotripsy.

Special considerations for children

In rare situations, a kid may require an ERCP to address recurring pancreatitis or bile stones. The test is performed in an operating room while the youngster is sedated.

Preparing children for a test or treatment can reduce anxiety, improve collaboration, and aid in the development of coping skills. Explaining what will happen throughout the exam, including what they will see, feel, hear, taste, or smell, is part of preparation.

What Happens after ERCP?

You are need to remain in the procedure area for one or two hours following your ERCP, until the sedatives wear off. You can then have someone drive you home. You'll probably want to spend the remainder of the day at home resting. Unless your doctor advises you otherwise, you can eat normally and take your regular medications following the treatment. You may get a sore throat for a day or two. After the surgery, you may need to spend the night in the hospital. If this is the case, your doctor will address it with you.

• When will I learn my ERCP results?

On the day of the surgery, your doctor will generally inform you of the ERCP results. If your doctor takes a small sample of tissue, known as a biopsy, it might take several days to acquire all the information. These findings take longer since the tissue must be examined and tested in a laboratory. Inquire with your doctor about the best manner to learn the results of your biopsy.

ERCP Complications

Complications directly related to ERCP account for up to 6.8 percent of all cases. A quarter of them are serious, requiring intervention, a blood transfusion of more than 4 units, or hospitalization for more than 10 days. The mortality rate is around 0.3 percent. Post-ERCP pancreatitis (PEP) occurs at a rate of 3.5 percent, making it the most common complication of the surgery. Pancreatitis is mild to moderately severe in 90% of patients.

Infections such as cholecystitis and cholangitis occur at an incidence of 1.4 percent. Gastrointestinal (GI) bleeding occurs in 1.3 percent of cases. Although duodenal and biliary perforations occur at a lesser rate of 0.6 percent, they have the greatest fatality rates among ERCP complications.

Other problems make for 1.3 percent of all complications. These include pneumothorax, retroperitoneal, mediastinal, and subcutaneous emphysema, hepatic hematoma, portal venous air embolism, splenic damage, post-sphincterotomy papillary or ampullary restenosis, duodenal blockage, and basket catheter impaction while extracting biliary stones.

Increased cannulation attempt duration (more than 10 minutes and possibly more than 5 minutes), pancreatic guidewire passage more than once, pancreatic injection of high-osmolality contrast material, previous pancreatitis, suspected sphincter of Oddi dysfunction, and female gender are all risk factors for PEP. Intraductal ultrasonography, inability to remove bile duct stones, endoscopic papillary balloon dilatation, and pancreatic sphincterotomy are all possible risk factors.

Greater PEP risk may be attributed to increased cannulation attempts associated with this operation, therefore precut sphincterotomy is not a clear risk factor. Needle-knife fistulotomy is preferred over other precut methods because it has less problems, such as PEP. Other patient-related risk factors include prior PEP, younger age, lack of chronic pancreatitis, and normal blood bilirubin levels.

If serum amylase levels are less than 1.5 times the upper limit of normal 2-6 hours after ERCP, they are deemed normal. Serum lipase levels acquired at the same time are also deemed normal if they are less than four times the upper limit of normal. Endoscopic papillary balloon dilation should last more than one minute when indicated.

PEP is reduced by the use of nonsteroidal anti-inflammatory medications (NSAIDs). As a result, it is suggested that patients having ERCP receive regular rectal diclofenac or indomethacin before or after the surgery. PEP can be reduced by aggressive hydration with lactated Ringer's solution. If NSAIDs are contraindicated and preventive pancreatic stenting is not possible, sublingual nitroglycerin or bolus injection of 250 micrograms of somatostatin should be explored as an alternative in high-risk individuals. Topical epinephrine should not be used on a regular basis.

Somatostatin, octreotide, ceftazidime, and anti-protease medicines such as nafamostat, gabexate, and ulinastatin are also potentially helpful. They are still not advised for PEP. 

It is not suggested to utilize low-osmolality contrast materials on a regular basis. The number of cannulations attempts and the amount of contrast material injected should be kept to a minimum. The incidence of PEP is unaffected by patient posture. Carbon dioxide insufflation reduces post-procedure stomach discomfort and is thus advised. The wire-guided cannulation approach is suggested.

In high-risk patients, using short 5-Fr pancreatic stents rather than 3-Fr stents might reduce the chance of severe PEP to nearly nil. Retained stents must be removed within 10 days of being implanted. Manometry for the sphincter of Oddi is best performed with a modified triple-lumen perfusion catheter with quick aspiration or a non-water-perfused micro transducer catheter.

Outcomes

The relatively significant risk of ERCP emphasizes the need of having this surgery performed by qualified practitioners. It also helps to explain the shift toward therapeutic rather than diagnostic ERCP. Although the absolute complication risk for therapeutic ERCP is higher than for diagnostic ERCP, the potential advantages are also higher, and the risk-to-benefit ratio favors therapeutic ERCP.

Conclusion 

Although ERCP is a useful therapy for many bile duct illnesses, healthcare providers, particularly nurse practitioners, must be aware that it is also linked with significant morbidity. Patients who have cardiac risk factors should get a preoperative screening to reduce their risks.