Endoscopic retrograde cholangiopancreatography (ERCP) is a diagnostic procedure used to study diseases of:
- duodenum (the first portion of the small intestine)
- ampulla of Vater (small structure that opens into the duodenum and allows the exit of the bile ducts and pancreatic duct)
- bile ducts, to the first intrahepatic branches
- gallbladder
- pancreatic duct, called the “Wirsung duct”
It can provide important information in preparation for subsequent procedures or can serve as a surgical intervention, allowing the removal of stones in the bile ducts or relieving a blockage (to avoid intervention by traditional open surgery). ERCP is used in the diagnosis and treatment of the following conditions:
- obstruction of the main bile duct by stones, tumors, strictures (narrowing), or compression by adjacent organs
- Jaundice (yellowing of the skin) due to obstruction of the bile duct, which also causes dark urine and pale stools
- Persistent or recurrent upper subcostal abdominal pain that cannot be diagnosed by other tests such as MRI and CT scan
- diagnosis of pancreatic or bile duct cancer
- dysfunction of the sphincter of Oddi, located within the ampulla of Vater, which controls the flow of bile and pancreatic juice.
The procedure is performed with a long, flexible endoscope (a duodenoscope), about the diameter of a pen, which is guided and moved around the many curves of the stomach and duodenum. The modern duodenoscope uses a bundle of fine optical fibers and a chip to transmit light and digital video images to a monitor. It is introduced through the mouth, down the esophagus, stomach, and finally up into the duodenum. Once the ampulla of Vater has been identified, a small plastic catheter (cannula) is passed through it into the bile ducts and/or pancreatic duct.
Contrast dye is then injected and X-ray images of the bile ducts and pancreatic duct are captured. Another channel in the endoscope also allows other instruments to be passed to perform biopsies, insert stents or plastic or metal catheters to relieve obstruction of the bile ducts or pancreatic duct (caused by tumors, scars, fibrotic tissue,…) and make incisions using electrified instruments. Cytological (brushing) samples can be performed by introducing a brush-like instrument into the bile or pancreatic duct, which collects the exfoliated cells and allows for subsequent analysis.
An important procedure related to ERCP is echoendoscopy, which uses a similar endoscope that, in addition to the camera, has an ultrasound probe at its tip to examine the bile ducts, gallbladder, pancreatic duct, and pancreas by ultrasound. Ultrasound-directed needle biopsies of the pancreas can be taken through a channel in the endoscope.
A second and more recent procedure related to ERCP is the use of miniature endoscopes (Spyglass) that allow direct visualization of the bile and pancreatic ducts. Direct biopsies (Spybite) and other therapeutic interventions can also be performed.
Preparation
For the best possible result, the stomach must be empty: the patient should not eat anything after midnight before the exam and should not drink anything for eight hours before the procedure. Any antihypertensive medication should always be taken with a small amount of water early in the morning.
ERCP is usually best done under general anesthesia, although sometimes just IV sedation + local anesthesia can be given to reduce the gag reflex.
Procedure
The patient lies on his left side, intravenous medication or sedation is administered, and then the instrument is gently inserted through the mouth, down the esophagus, past the stomach, and into the duodenum. The instrument does not interfere with breathing.
When the patient is in a semi-conscious state, he can follow instructions (for example, change the position of the body). ERCP can last from fifteen minutes to an hour, depending on the skill of the doctor, the complexity of the procedure to be performed, the anatomy, and any abnormalities in that area. The procedure is not painful and only causes a foreign body sensation in the throat.
After the procedure, patients should be observed in the recovery area until most of the effects of the medications wear off, which usually takes 1 to 2 hours. The patient may feel bloated or slightly dizzy from the medications or the procedure. At the time of discharge, the patient must be taken home by a companion: it is recommended to remain at home for the rest of the day. The patient can resume normal activities the next day.
Side effects
ERCP is a highly specialized procedure, the outcome of which depends not only on the underlying pathology and the procedure to be performed, but also on the skill and experience of the physician who performs it. It is associated with very low risk when performed by experienced clinicians, with a 70-95% success rate and a 1-5% complication rate.
The most common complication is pancreatitis, due to irritation of the pancreas caused by the contrast medium, and it can occur even when the operator is highly experienced. This "shot" pancreatitis is usually treated in the hospital for 1 to 2 days.
Another possible complication is infection of the bile duct after the procedure, or of the biliary prosthesis (stent) that can become blocked over time.
Other serious risks, including intestinal perforation, drug reactions, bleeding, and inhibition of respiration, are rare.
Arrhythmias and heart attacks are extremely rare and are mainly due to sedation.
In the event of complications, patients are frequently hospitalized, but surgery is rarely required.