Prevention and management of ERCP-related complications

Pancreatic stent placement

There are many reports on the usefulness of pancreatic stent placement to prevent PEP. Mazaki et al.^[3] performed a meta-analysis of 14 randomized controlled trials and reported a significant reduction in PEP incidence in the prophylactic pancreatic stent placement group with respect to the group without stent placement. The authors concluded that pancreatic stent placement was useful in the prevention of PEP^[3]. Mine et al.^[4] also recommended prophylactic pancreatic stent placement in patients at high risk of PEP. The stents used were spontaneous dislodgement pancreatic stents^[4]. Regarding stent diameters, Zolotarevsky et al.^[5] confirmed that the placement success rate was higher with 5Fr than that with 3Fr stents, but there was no difference in the PEP prevention effects according to the size. Because a 3Fr stent requires a 0.018-inch guidewire, manipulations may be difficult and fluoroscopy results can be poor. With a 5Fr stent, the procedure can be performed with a small guide wire and placement takes less time. Therefore, 5Fr pancreatic stents are recommended^[6]. That said, adverse events related to pancreatic stents may occur, including damage to the pancreatic duct, inward migration of the stent, and pancreatitis due to stent occlusion^[7-8]. Because there is a risk of pancreatitis onset if the pancreatic stent does not spontaneously dislodge, the stent should be endoscopically removed in such cases^[9]. Of note, approaching the pancreatic duct again to place a pancreatic stent after treating the bile duct may actually increase the risk of PEP. Pancreatic stents should be aggressively placed if a guide wire is located in the pancreatic duct, such as during pancreatic duct injection of a contrast or pancreatic guide wire cannulation. However, when only the bile duct is treated, whether to place pancreatic stents should be considered on a case-by-case basis.

Wire-guided cannulation

Because the injection of a contrast agent into the pancreatic duct may be a risk factor for PEP, wire-guided cannulation (WGC), wherein a guide wire is cannulated into the bile duct without injection of a contrast agent, was developed. It is reported to be associated with lower PEP incidence compared to conventional contrast-enhanced methods and increased rate of deep bile duct cannulation^[10]. It is widely used in the Western countries as the standard procedure for bile duct cannulation. Meanwhile, a multicenter, joint randomized controlled trial in Japan showed no significant difference in the PEP incidence and deep bile duct cannulation rate between the WGC method and conventional contrast-enhanced method^[11]. However, further studies will be needed in the future on the selection of cases indicated for the WGC method. If the bile duct cannulation is challenging, we recommend that a prompt switch to another method to help prevent the onset of PEP.

Papillary perforation, bile duct perforation

Papillary perforation may also occur during EST, EPBD, and endoscopic papillary large balloon dilation (EPLBD), as well as during insertion of biopsy forceps and basket forceps into the common bile duct after EST and EPLBD. EST should be performed carefully so that incision is not made in an improper direction or an unnecessarily large incision is avoided. When perforation is suspected in ERCP, it is preferable to perform ERCP using CO₂ gas, so that the retroperitoneal space would not be widened due to pressure from the transport gas. It is important to perform sufficient bile duct drainage and minimize the collection of intestinal juices and infection in the retroperitoneal space; this facilitates conservative treatment. For papillary perforations, endoscopic nasobiliary drainage or biliary stent should be placed in the common bile duct, and the closure of the perforation should be attempted using clip forceps. Thereafter, a gastric tube should be placed, while conservative observation is performed by administering antibiotics and proton pump inhibitors. A papillary perforation has been treated conservatively with compression closure by placing a covered metallic stent^[25] [Figure 4]. Similar actions are performed in cases of papillary or bile duct perforation by a basket forceps that is associated with common bile duct stone removal. Generally, papillary perforations and bile duct perforations are caused by treatment devices, and they can usually be alleviated by bile duct drainage, gastric tube placement, and antibiotics administration^[26]. Post-ERCP, free air should be checked for, as well as fluid collection in the retroperitoneal space and ascites on an abdominal computed tomography (CT). Surgical treatment should be considered in cases where progression of symptoms such as fever and abdominal pain, elevated inflammatory response, and an increasing trend of retroperitoneal space fluid collection and ascites on CT are observed.

Figure 4. Case of papillary perforation after endoscopic sphincterotomy. The bile duct (arrowhead) and the perforation (arrow) were confirmed. Covered metallic stent was placed for the purpose of compression closure, and endoscopic nasobiliary drainage was performed. It subsequently conservatively alleviated the complication, and surgical treatment was avoided.

Duodenal perforation

Duodenal perforation occurs normally during scope insertion into the descending duodenum and stretching procedures. Since adhesions of the duodenum due to previous abdominal surgeries or cancer invasion may cause perforations, it is important to perform ERCP with an awareness of preventing duodenal perforation, such as performing ERCP without the stretching procedure. Clip closure with a clip can be performed for duodenal perforations with additional conservative treatment^[27]. Recently, the efficacy of over-the-scope clip for perforations during pancreaticobiliary endoscopy has been reported^[28]. Duodenal perforations are usually direct injuries of the intestinal wall due to endoscopy and have large perforation hole. Hence, careful consideration is required for the indication of endoscopic closure, and surgical closure of the injury should be considered first.

Acute cholangitis

Sepsis may occur after emergency ERCP for acute obstructive septic cholangitis. To avoid an increase in the pressure within the bile duct, ERCP should be performed initially with a small amount of contrast agent and then with endoscopic nasobiliary drainage or biliary stent drainage alone. Lithiasis treatment should be performed following cholangitis control.

Furthermore, during drainage for malignant hilar obstruction, it is preferable to not perform bile duct contrast imaging on the other side of the bile duct expected for drainage, so as to prevent cholangitis^[29]. It is important to preoperatively determine the bile duct expected for drainage in advance by CT or magnetic resonance cholangiopancreatography. Although there are reports that unilateral drainage has lower risk for cholangitis than bilateral drainage^[30-31], examination on a case-by-case basis is necessary as the obstruction state will differ depending on the case.

Acute cholecystitis

Acute cholecystitis is a complication that may occur after metallic stent placement^[32-33]. The risk is particularly high in cases where a tumor extends to the cystic duct and where the cystic duct is obstructed by a covered metallic stent. Furthermore, the risk has been reported with the presence of stones in the gallbladder and the filling of the gallbladder with contrast during the examination^[14]; adequate attention should be taken to prevent excessive contrast. If there is no improvement with conservative therapy, percutaneous transhepatic gallbladder aspiration or percutaneous transhepatic gallbladder drainage should be considered. In the case of cholecystitis due to a covered metallic stent, removal of the stent and replacing with a plastic stent or uncovered metallic stent should be considered.

Stent migration

Migration of plastic stents into the bile duct has been observed. Proximal stent migration was reported in approximately 5% of cases in an initial report^[34]. Malignant strictures, larger diameter stents, and shorter stents were significantly associated with proximal biliary stent migration^[34]. In case of proximal migration, a guide wire could be passed through the inside of the plastic stent, and the stent could be removed with a Soehendra^® Stent Retriever or a balloon catheter [Figure 5]. In cases where a guide wire could not be passed through the inside of the stent, the distal end could be grasped with a basket forceps, grasping forceps, or polypectomy snare, and the stent could recover under fluoroscopic guidance.

Figure 5. A bile duct plastic stent migrated into the bile duct. A contrast-enhanced cannula was guided under fluoroscopic guidance to the distal end of the plastic stent, and then a guide wire passed through the inside of the plastic stent. A Soehendra^® Stent Retriever was covered over the guide wire and guided under fluoroscopic guidance, the end locked onto the stent, and then withdrawn to the duodenum under fluoroscopic guidance.

Bile duct bleeding

Bleeding from the tumor may occur in malignant bile duct stricture. Although this bleeding usually stops spontaneously, a covered metallic stent could be placed and pressure hemostasis could be performed in cases where bleeding from the tumor is continuous and the anemia progresses (video). In cases where hemostasis is still difficult to achieve, hemostasis by interventional radiology should be considered.