Endoscopic Retrograde Cholangiopancreatography

Endoscopic retrograde cholangiopancreatography (ERCP) enables x-ray visualization of the pancreatic duct and the bile ducts by dye injected through the endoscope.

Indications

Diagnostic indications include determining the cause of jaundice and identifying the site of an obstruction with a high degree of accuracy. The procedure also can demonstrate ductal abnormalities in a nonjaundiced patient when the clinical presentation suggests biliary disease, pancreatic cancer, or pancreatitis. ERCP helps evaluate chronic pancreatitis or pancreatic pseudocyst preoperatively. Magnetic resonance cholangiopancreatography is a noninvasive procedure that may replace diagnostic, but not therapeutic, ERCP. If symptoms, signs, or laboratory tests suggest common bile duct stones, ERCP is indicated to diagnose and remove the stones before laparoscopic removal of the gallbladder, because exploring the common bile duct during laparoscopic cholecystectomy is difficult. Pressure measurements, which can be performed in highly specialized medical centers, help diagnose dysfunction in the sphincter of Oddi.

ERCP is not indicated for evaluating abdominal pain in the absence of symptoms, signs, or laboratory findings that suggest biliary tract or pancreatic disease, nor is it indicated for evaluating suspected gallbladder disease without evidence of bile duct disease. ERCP has little value diagnostically when pancreatic cancer has already been demonstrated by ultrasound or CT.

Therapeutic indications include removal of stones from the bile duct. In endoscopic sphincterotomy, the muscular fibers at the distal bile duct sphincter are cut to allow the passage of stones that cannot pass spontaneously because of the narrow orifice or large stone size. Emergency sphincterotomy is the procedure of choice for acute gallstone pancreatitis and for stone-induced acute cholangitis. Large stones may be crushed by a lithotriptor or may be dissolved over several days by chemical instillation via an indwelling nasobiliary tube placed through the sphincterotomy. A benign stricture may be dilated with a balloon. A malignant pancreatic tumor obstructing the bile duct can be relieved by positioning a stent in the common bile duct. With relief of jaundice, the elderly patient will become more comfortable even as the disease advances. Therapeutic ERCP is often used for biliary complications of laparoscopic cholecystectomy (eg, duct obstruction from clips, bile leakage from the cystic duct stump, removal of retained stones). Currently, stones in the gallbladder cannot be treated endoscopically.

Contraindications and Procedure

Absolute contraindications include a recent myocardial infarction and perforated viscus.

The patient should not eat or drink for 6 hours before the procedure to empty the stomach and duodenum. If the patient has recently ingested barium, an x-ray should be obtained to ensure that the barium is not superimposed on the areas of interest. An IV opioid and/or a benzodiazepine is given for sedation.

An endoscope is passed orally to the duodenum. Then under direct vision, a cannula is placed into the ampulla of Vater. Under fluoroscopic monitoring, a dye is injected that flows retrograde (or counter) to the normal flow of secretions and makes the common bile duct and its tributaries or the pancreatic duct and its tributaries opaque and visible on an x-ray monitor. Because of the position of the biliary tree, a cholangiogram is more difficult to obtain than a pancreatogram, but an experienced examiner can visualize the desired duct in > 90% of cases. An ultrathin fiberscope, the size of a cannula, which can be passed through the ERCP instrument directly into the ducts for direct intraductal visualization, is under investigation.

Complications

Perforation and drug reactions are rare; other complications of ERCP are pancreatitis, which occurs in < 1% of patients and is usually mild, and infection, which is less common and occurs primarily in patients with duct obstruction. Sphincterotomy has a 1.5% mortality rate and an overall complication rate (including bleeding) of < 10%, which is lower than that of similar surgical procedures.