Management of gastroduodenal stent-related complications

Abstract

Introduction

Endoscopic placement of a gastroduodenal self-expandable metallic stent (SEMS) is a safe and minimally invasive intervention for patients with malignant gastric outlet obstruction (GOO).1 Several prospective studies have demonstrated the efficacy and safety of gastroduodenal SEMS in the palliation of malignant GOO with technical success rates of 89% to 100% and clinical success rates ranging from 72% to 88%.2–8 Because patients with malignant GOO are generally older and have short anticipated life expectancy, an endoscopic stent placement may be preferable to a surgical gastrojejunostomy as it leads to faster resumption of food intake and shorter hospitalization compared with an open surgical intervention.9,10 One major shortcoming of SEMS, however, is a frequent need for re-interventions due to stent-related complications, such as occlusion and migration. With continuing advances in oncologic therapy and improved survival in patients with malignancy, these complications may be encountered more frequently.

Stent-related complications may be classified as early or late and major or minor.11 Early major complications occurring within the first week include stent migration, perforation, bleeding, severe pain and biliary obstruction. Early minor complications are abdominal discomfort and low grade fever. Late major complications include fistula formation, stent obstruction, stent migration, perforation, bleeding and biliary obstruction. Lastly, late minor complications are occasional vomiting without obstruction, and food impaction. A systematic review of 606 patients with malignant GOO treated with stent placement reported an overall complication rate of 27%, with stent occlusion and migration accounting for the vast majority.12 Correctly identifying and managing SEMS-related complications in a timely manner is essential in maintaining effective palliation in patients with malignant GOO.

In this review article, we discuss the management of complications arising from the placement of gastroduodenal SEMS in patients with malignant GOO.

Stent Occlusion

Tumor ingrowth refers to growth of the tumor through the interstices of a stent, and overgrowth refers to growth beyond the length a previously placed stent (Fig. 1). Stent occlusion due to tumor ingrowth or overgrowth occurs in 9% to 26% of patients with malignancy undergoing SEMS placement for GOO (Table 1).2–8,12 A recent large retrospective series showed that the time to stent occlusion was shorter in patients with pancreatic cancer compared with those with other types of malignancies (1.6 vs 4.3 months, P = 0.06).13 Although not statistically significant, the difference could be due to the aggressive tumor biology associated with pancreatic cancer.

In patients with stent occlusion, a stent-in-stent placement of a secondary gastroduodenal SEMS can be performed to re-establish stent patency. Four retrospective studies (3 Korean and 1 Japanese) have evaluated the outcome of a secondary SEMS placement predominantly in patients with gastric cancer (Table 2).14–17 These studies reported excellent technical and clinical success rates with a median patency of a secondary stent ranging from 3 to 6.3 months and stent occlusion rate of 10% to 34%. One of the studies found that complications occurred more frequently when the distal end of an additional stent was placed distal to a primary stent,16 which may be due to an impaired flexibility and conformity to the curved anatomy of the duodenum at the overlapping portion of stents.17,18 Although serious complications were uncommon, one study reported an alarmingly high perforation rate of 14%, which was attributed to the strong axial force of a SEMS.14 In addition, one of the technical challenges associated with a secondary SEMS placement is the difficulty inserting a guide-wire through the lumen of a primary stent under fluoroscopic guidance.16 If successfully performed, however, a stent-in-stent secondary SEMS placement can provide adequate symptomatic relief in patients with stent occlusion. More simple techniques to manage stent occlusion include the endoscopic or fluoroscopically guided removal of food impaction using foreign body removal devices19 and balloon dilation of an occluded or angulated stent (Fig. 2).

Alternatively, gastrojejunal bypass surgery can be performed to accomplish the anastomosis between the stomach and jejunum. Recently, endoscopic ultrasound (EUS)-guided gastrojejunostomy has been proposed as a minimally invasive means of establishing an anastomosis in patients who are not ideal candidates for surgery. In this technique, a gastrojejunal fistula is created by obtaining an access to the jejunum via an EUS-guided needle, placing a guidewire through the needle and dilating the tract over the wire using a dilator catheter, balloon and/or electrical cautery needle. Subsequently, a lumen-apposing stent is placed across the fistula (Fig. 3). This technique has recently been described in 2 case reports.20,21

Nevertheless, it should be noted that these patients who were fortunate enough to outlive primary stents have extremely short life expectancy, and serious complications including perforation can occur with these interventions. The benefits and risks of a secondary intervention should therefore be weighed carefully for each individual patient.

Stent Migration

Stent migration occurs in 2% to 10% of patients who undergo gastroduodenal SEMS placement for malignant GOO (Table 1, Fig. 4).2–8,12 There have been attempts to improve the design of SEMS and develop devices to prevent stent migration. Although an uncovered SEMS is prone to an occlusion due to tumor or tissue ingrowth through the mesh-like framework, the mesh allows tissue embedding to minimize the risk of migration, and the access to the papilla when a biliary drainage is indicated. Several studies have shown that stent migration occurs less frequently with uncovered compared with covered SEMS22–24 and one study has demonstrated that an uncovered SEMS was associated with lower re-intervention rates for stent-related complications compared with a covered SEMS (although the rate of migration was similar between the two groups).25 Therefore, an uncovered SEMS is generally considered a better choice for GOO than a covered SEMS. Recently, a new partially covered “big cup” SEMS has been developed in the hope of reducing both stent migration and tissue ingrowth but a trial was terminated prematurely due to three proximal stent migrations in the first six patients necessitating endoscopic removal and placement of another SEMS.26 Lastly, the use of an endoscopic clip to fix the proximal end of a SEMS to the upper gastrointestinal mucosa to prevent migration has been reported in small series27–29 but has not been validated in large prospective trials.

Migration of a gastroduodenal SEMS can be managed in several ways—observation until spontaneous passage of a stent in the stool, endoscopic or surgical removal of a stent, and a secondary SEMS placement. However, as the downward migration of gastroduodenal SEMS carries the risk of intestinal obstruction and perforation, the watch and wait strategy should be discussed with a surgical team for potential emergency laparotomy. In a series reporting the outcomes of migrated SEMS, 2 out of 6 patients with migrated gastroduodenal SEMS required a surgical removal, whereas only 1 out of 64 migrated esophageal SEMS required surgery.30

Yoon et al31 described three different techniques (standard, proximal mesh and eversion) for stent removal using a retrieval device consisting of a hookwire, a dilator, a sheath and a guide-wire. In the standard technique, the hookwire is manipulated to grasp the drawstring at the proximal end of the stent to collapse the proximal stent into the sheath. The sheath, hookwire, and stent are then removed all together. If the hookwire fails to grasp the drawstring, the proximal third of the stent is grasped and removed in its expanded state. The eversion technique is where the distal part of the stent is grasped and the stent invaginated into itself during removal. The study reported the successful removal of 4 out of 6 gastoduodenal SEMSs (4 malignant and 2 benign strictures). However, the removal of a gastroduodenal stent can be more technically challenging compared with an esophageal stent. In the two patients with unsuccessful stent removal, stents had migrated into the gastric fundus where the proximal end of the stent faced an unfavorable direction and a guidewire insertion was not possible despite air inflation and change in the position of the patients.

Lastly, the placement of a secondary stent could be considered, either overlapping a migrated stent or following its removal. A potential issue with this approach is the risk of the migration of a secondary stent. A recent small series have demonstrated that the long-term patency of a secondary stent was achieved in the majority of patients with a covered primary stent (86%, 6/7) but the migration of a secondary stent was observed in half of the patients with an uncovered primary stent (50%, 2/4).15

In summary, the evidence for endoscopic management of migrated gastroduodenal SEMS is predominantly based on small series and further prospective studies are needed to validate the effectiveness of these techniques. The management plan should be discussed with a surgical team if there is a potential risk of small bowel perforation or obstruction secondary to the downward migration of a stent.

Biliary Obstruction

One unique complication of gastroduodenal SEMS is the precipitation of cholangitis or biliary obstruction caused by compression of the papilla (Fig. 5).12,32,33 Prospective studies have shown that biliary obstruction occurs in 2% to 6% of patients following a gastroduodenal SEMS placement for malignant GOO (Table 1). Concomitant biliary obstruction with malignant GOO is also very common, and occurs in 59% of patients with pancreatic cancer.34 Because the papilla cannot typically be accessed after the placement of a gastroduodenal SEMS, a biliary SEMS should be placed before a gastroduodenal stent when biliary obstruction is present or impending.35 When a biliary drainage is indicated after a gastroduodenal stent has been placed, biliary stenting through the mesh of the duodenal SEMS, percutaneous transhepatic biliary drainage or EUS-guided approach are all potential solutions.

Perforation

As with SEMS in other areas of the gastrointestinal tract, perforation is the most serious complication of a gastroduodenal SEMS placement, occurring in 0.5% to 5% of patients (Table 1).2–8,12 Several strategies to minimize the risk of perforation have been suggested, including the use of lower axial-force SEMS, partially covered SEMS to prevent tumor ingrowth or overgrowth, and systemic chemotherapy to prevent local tumor progression.36,37 Stent strut perforation of the bowel wall is an extremely rare complication with few reported cases.38–40 Perforation is usually managed with surgical repair, or endoscopic placement of a covered stent (Fig. 6).

Bleeding

Bleeding occurs in up to 6% of patients with a gastroduodenal GOO.2–8,12 The majority of cases are mild and can be managed effectively with simple endoscopic interventions such as cautery and clip placement. Catastrophic, fatal bleeding is rare but has been described in a case report.41 Potential therapeutic options for severe bleeding include radiotherapy for a diffuse oozing and vascular embolization for a documented arterial bleed.

Severe Pain

Pain occurs in 2% to 8% of patients with a gastroduodenal SEMS2–8,12 and can be treated with oral analgesia. Stent removal is rarely required as the pain is usually transient. In patients with pancreatic cancer, pain is often due to the underlying disease itself and can persist and celiac plexus intervention has been shown to provide effective pain relief.42–46

Fistula Formation

Fistula formation due to a gastroduodenal SEMS is rare. In a series of 46 patients with malignant GOO treated with a gastroduodenal SEMS, one patient developed an aortoenteric fistula from stent erosion in the setting of a previous pancreaticoduodenectomy. The patient was treated with an endovascular aortic stent followed by definitive repair.46

Summary and Conclusion

Gastroduodenal SEMS in the setting of malignant GOO are frequently complicated by stent occlusion and migration which can be effectively managed either endoscopically or surgically.

Biliary obstruction also occurs commonly and may require percutaneous or endoscopic (usually endoscopic retrograde cholangiopancreatography [ERCP], or EUS if ERCP is unsuccessful) decompression. Less frequent complications include perforation, bleeding, pain and fistula formation. The evidence for interventions such as a secondary stent placement and stent removal are predominantly based on small series and further prospective studies are necessary to demonstrate the efficacy of these techniques. In addition, given the very limited life expectancy of these patients with an advanced malignancy, the benefits and risks of a secondary intervention should be weighed carefully for each individual patient.

Acknowledgments

Fig. 3E and 3F images are courtesy of Shayan Irani, MD, Virginia Mason Medical Center.

Article information

References