**6. Malabsorption**

The procedures that lead to a barrier development of duodeno-jejunal or gastroduodeno-jejunal contact are endoscopic, innovative interpretations of the mode of action of the surgically created gastric bypass. The implantation of a plastic liner into the lumen of these organs can result in good glycaemic control and, in addition, weight reduction. These procedures are named gastrointestinal bypass liners (EndoBarrier®, ValenTx™). They are particularly indicated for patients with poorly adjustable diabetes mellitus type II.

### **6.1 The EndoBarrier**

The EndoBarrier consists of a single use endoscopic system including a liner, delivery system, and retrieval system. A 65 cm teflon covered sleeve is placed into the small bowel and can remain in situ for up to 3–12 months. Endoscopically implementation is done under general anesthesia. Placement of anchor and liner is controlled by endoscopy and fluoroscopic guidance. The anchors at the proximal end of the sleeve looks like a crown, consists of nitinol, which functions as a self-expandable stent. This allows fixation to the duodenal bulb distal to the pylorus, but proximal to the ampulla Vateri. The proximal and distal open liner ensures the passage of chyme from the stomach while bypassing the duodenum. Along the outside of the liner, pancreatic juices and bile will enter from the ampulla Vateri, thereby avoiding contact with gastric contents until these exit the sleeve in the jejunum. The EndoBarrier mimics the malabsorptive effects of the RYGB.

Results: Betzel and colleagues [19] reported 2020 about 44 patients treated with EndoBarrier-Devices. Twenty patients required early removal due to AEs(55%). During dwelling time, body weight decreased significantly (15.9 kg; TBWL 14.6%). HbA1c decreased non-significantly. In total, 68% of the patients experienced at least one AE. Patel et al. [31] 2018 reported about similar results in a multicenter, non-randomized clinical trial with 45 obese patients. Fourteen patients required early removal (24%). Significant reductions in weight, BMI and glycaemic control were observed during the device insertion period.

Complications: The ASGE Bariatric Endoscopy Task Force reported 2015 about an AE rate of 12.66% in 271 implantation [10]. Serious adverse events included migration (4.9%), GI bleeding (3.86%), sleeve obstruction (3.4%), liver abscess (0.126%), cholangitis (0.126%), acute cholecystitis (0.126%), and esophageal perforation(0.126%).

*Bariatric Surgery—from the Non-surgical Approach to the Post-Surgery Individual Care… DOI: http://dx.doi.org/10.5772/intechopen.95259*

#### **6.2 The ValenTx and its successor**

The ValenTx-System is a gastro-duodenal-jejunal liner system which has to be inserted in an endoscopic/laparoscopic rendezvous technique. The system, a 120 cm long fluoropolymer liner with a proximal and a distal cuff, is primarily placed into the jejunum with a delivery catheter. The proximal cuff is anchored at the level of the Z-line of the GE junction and anchored with fullthickness sutures deployed in a circumferential manner. The successor of the ValenTx is a 120 cm long fluorpolymer sleeve which could implement without laparoscopy.

Results: Sandler et al. reported 2018 in sum about 32 obese patients (Mean BMI 42.3Kg/m2 ) treated with the successor ValenTx for 12 months. Implantation and removal of the device according to the study concepts was possible in all patients. EWL after one year was 44.8% [20].

Complications: Implantation related AEs were mild (epigastric pain, heartburn or acid reflux, regurgitation, vomiting, dysphagia, and nausea). Longtime AEs were obstructions by knots or kinking. In one patient laparotomy for sleeve explantation was necessary.

#### **6.3 The duodenal mucosal resurfacing (DMR)**

DMR potentially mimics some of the mechanisms of action of bariatric surgery in a minimally invasive manner. The DMR procedure is performed using specially designed catheters which are advanced over a guidewire next to the endoscope. It is a single, minimally invasive endoscopic procedure that involves circumferential hydrothermal ablation of the duodenal mucosa resulting in subsequent regeneration of the mucosa. Before ablation, the mucosa is lifted with saline to protect the outer layers of the duodenum. The DMR procedure could be performed under either general anesthesia or deep sedation with propofol.

Results: Van Baar et al. reported 2020 about 37 of 46 patients underwent complete DMR (80%), 36 were finally analyzed; in remaining patients, mainly technical issues were observed [32]. Weight loss was observed in the first 4 weeks, overall was no significant weight loss registered but a significantly decrease of HbA1c and needed anti-diabetic medications. The principle of DMR also allows good glycemic control, but does not lead to significant weight loss [33].

Complications: In the study of Van Baar et al. [32] twenty-four patients had at least one AE (52%) related to DMR. Of these, 81% were mild. One SAE and no unanticipated AEs were reported.

### **7. Endoscopic bypass**

In the context of NOTES development, endoscopically guided gastrojejunal bypass systems have already been developed and successfully performed in the pig model [34]. In the present publications magnets are used, which are applied via the working channel of the scope. These "intelligent" magnets are composed in square or hexagonal form intraluminally. Two such magnets, which act on each other with a force of 600-800 g, cause an anastomosis by reducing the blood supply of the enclosed tissue. This results in a gastro-jejunal [35] or jejuno-ileal [21] anastomosis.

The incisionless magnetic anastomotic system (IMAS; GI Windows, West Bridgewater, MA, USA) is a novel self-assembling magnetic device that allows for side-to-side anastomosis with enteral diversion.

Results: E. Machytka and colleagues [21] performed a prospective, single-arm pilot study, published in 2017. They evaluated the clinical outcomes, safety, and efficacy of IMAS placement and creation of a PJD in a total of 10 patients. At 12months, patients had an EWL of 40.2%, and a decrease in HbA1c of 1.9% and a decrease in fasting glucose levels of 37% in diabetic patients.

Complications: No adverse events were reported.
