During resectional procedures, endoscopy allows for visualization of staple lines to assess for bleeding or leakage. An endoscopic air leak test with an anastomotic or sleeve staple line submerged under saline can identify leaks in many cases. This method of leak testing has been found superior to methylene blue infusion via an orogastric tube with laparoscopic visualization [7]. Haddad et al. reviewed 2,311 gastric bypass cases at their institution from 2002 to 2011, in which 2,308 (99.9 %) successfully underwent intraoperative upper endoscopy to assess the gastrojejunostomy; 46 (2 %) clinically significant leaks were noted and received immediate intraoperative surgical repair. Forty-four required no additional intervention and two of the 46 initial leaks recurred and required additional treatment postoperatively. Twenty-five (1.1 %) patients developed early strictures, which were detected and treated with endoscopic dilation within 90 days of the index operation. No major complications occurred as a result of the endoscopies [8].

In addition to leaks, intraoperative and early postoperative gastrointestinal hemorrhage can be detected and treated endoscopically. Clinically relevant endolumenal bleeding occurs in 1–4 % of patients undergoing gastric bypass. Hematemesis and hematochezia are common presenting signs. Although some bleeding occurs from sites inaccessible to upper endoscopy requiring conservative or reconstructive approaches, when the bleeding originates from an accessible single staple line, an anastomotic staple line, or postoperatively from marginal ulcers, treatment can be accomplished utilizing endoscopic hemostatic injection or clip application in addition to guidance for laparoscopic oversewing of the suspect area. Energy sources are generally avoided to prevent delayed thermal injury and perforation. When the hemorrhage originates from bypassed gastrointestinal segments, inaccessibility of the bypassed anatomy adds additional diagnostic and therapeutic challenges. The threshold for operative intervention is lower and remnant gastrectomy may be necessary to remove the entire source. Therapeutic endoscopy for gastrointestinal bleeding is optimally performed in an operative theater under general anesthesia with endotracheal intubation to reduce the risk of aspiration as well as to allow for prompt formal operative intervention if necessary. Hemorrhage originating from a marginal ulcer can be addressed in a similar fashion as peptic ulcers utilizing the techniques described previously. Complications of therapeutic intervention for bleeding include those related to airway management, aspiration, and pulmonary complications. Obtaining hemodynamic stability is imperative prior to proceeding with a minimally invasive approach, such as therapeutic endoscopy, and blood products should be immediately available. Awareness that rebleeding occurs in up to 50 % of cases when a blood vessel is visible is important and surveillance endoscopy prior to patient discharge may be useful in preventing urgent repeat endoscopy thereafter in those patients [2, 9].

The endoscopic techniques described previously for gastric bypass are also applicable in treating complications of the single staple line of the gastric sleeve as well as the multiple staple lines of the biliopancreatic diversion with duodenal switch.

In some circumstances, the endoscope can serve as a calibration tool during bariatric surgery. Sleeve gastrectomy is often performed with a transorally placed bougie of 32–38 French diameter to calibrate the diameter of the gastrectomized stomach and guide stapler placement. A 10–12 mm outside diameter (31.4–37.7 French) endoscope can also be used to calibrate a sleeve gastrectomy in place of a bougie. This technique potentially reduces the risk of esophageal injury during insertion of the bougie through direct visualization [10]. Reduced visceral trauma is also appreciated as the endoscope is introduced a single time to serve in the role of sleeve calibration as well as intraoperative inspection of the sleeve staple line.

Marginal ulcers typically present as severe epigastric discomfort, which is temporarily resolved with gastrointestinal cocktails consisting of anesthetic and mucosal coating agents such as viscous lidocaine and sucralfate along with antisecretory medication (Fig. 35.2a, b). These ulcers will often heal with conservative management over the course of several weeks. On rare occasion, recurrent and refractory marginal ulcers require anastomotic revision involving healthier adjacent small bowel and stomach for definitive treatment.

After gastric bypass or biliopancreatic diversion with duodenal switch, progressive food intolerance 3 or more weeks after surgery suggests stenosis of the proximal anastomosis. The reported incidence is 3–12 % and is typically hallmarked by dysphagia, nausea, and vomiting [3]. Endoscopic balloon dilatation with a 12–20 mm balloon is the preferred initial treatment modality, although this can also be achieved via wire-guided bougie dilatation as well. The balloon is inserted 2 cm or less into the stenosis and it is dilated to allow a smaller bore scope with a working channel through the stenosis. When this is achieved, the mid aspect of the balloon is positioned at the stenosis and fully inflated for 60 s. This can be done two or three times during the endoscopy for more effectiveness. If needed, the procedure can be repeated 2 weeks later and serially thereafter. The success rate reported is around 90 %. The presence of a marginal ulcer will complicate dilatory treatment. In this case, medical therapy is most appropriate as long as the anastomosis is patent. Complications associated with balloon dilation are associated with blind insertion. The placement of covered stents has limited value in the treatment of anastomotic stricture, but may be used in select refractory cases [2]. Surgical revision for stenosis is rarely necessary.

Stenosis after sleeve gastrectomy is less common but usually presents acutely. Balloon dilatation and stenting are feasible, with the risk of perforation or stent migration. Conversion of the sleeve to a formal Roux-en-Y gastric bypass serves as definitive treatment in the case of failed repeated endoscopic treatments.

Although rare, one of the more concerning perioperative complications following gastric bypass, biliopancreatic diversion with duodenal switch, and sleeve gastrectomy includes staple line leak. Leaks after gastric bypass and duodenal switch typically occur at the proximal anastomosis. Following sleeve gastrectomy, they most commonly occur along the most proximal staple line near the esophagogastric junction and often present within the first or second week following surgery. The mainstay of the treatment of an anastomotic or staple line leak is source control using wide drainage and distal enteral access for nutrition. The use of fully covered stents to assist with source control and divert enteral flow downstream is gaining favor in that this allows the surrounding tissues to heal and close the leak over the course of 6–8 weeks. Fully covered stent migration is a familiar problem for endoscopists who frequently treat patients with sleeve-related leaks. Although the initial stent is deployed thus covering the leak, distal migration into the sleeved portion of the stomach with the distal landing zone resting against the pylorus results in uncovering of the leak proximally. Deploying an identical stent above and inside the initial stent often results in telescoping of the stents with both resting below the leak. Attempts to secure proximal stents in place with clips and sutures have been marginally successful. The use of partially covered stents results in rapid ingrowth of the esophagogastric mucosa through the stent interstices resulting in significant difficulty in stent removal thereafter. Nesting two different fully covered stents, however, utilizes the structure of each to benefit the combination of the two. Deploying a distal stent with “dumbbell”-shaped proximal and distal landing zones and then deploying a proximal stent (of similar diameter) with simple flared ends allow for the distal flared end to nest within the proximal “dumbbell” of the distal stent, essentially stacking the stents and locking them in place until the leak has healed and proximal removal is indicated (Fig. 35.3).

In addition to source control and distal feeding to treat leaks, the leak itself can be plugged or closed at the time of initial endoscopy. To augment healing of the tissues involved in the leak, endoscopic coagulation can be used to freshen the involved surfaces, followed by endoscopic suturing, or the placement of fibrin glue, hemoclips, or transmural clips. A French clinical trial is currently enrolling patients with sleeve-based leaks to determine the effectiveness of large transmural clips to reduce the healing time of these leaks.

Although leak following adjustable gastric banding is of minimal concern, the likelihood of band erosion into the stomach after several years becomes a reality in approximately 1 % of patients. Once this is diagnosed, the band is no longer functional and removal is necessary. Endoscopic removal involves cutting the band endoscopically with transoral removal of the band and tubing following abdominal wall disconnection of the port.

For patients who have undergone adjustable gastric banding and present with sudden intolerance to per oral intake, band slippage is a concerning possibility. Endoscopic findings typically include an enlarged gastric pouch with a very narrow or acutely tilted passage into the distal stomach. Mucosa ischemia may be present. This is also easily identified via upper gastrointestinal radiographic studies. Prompt treatment includes surgical repositioning of the band in the correct position on the gastric cardia.

As previously discussed, although some complications following index bariatric surgeries will require immediate surgical revision, many can be approached using definitive transoral flexible endoscopy with or without laparoscopic assistance.