Bariatric Endocrinology: Obesity, Adiposity and Adiposopathy
October 2021
Volume 10, Issue 3

Chapter 4: Endoscopic Procedures for Weight Loss

AACE Clinical Case Reports. 2017;3:4

Adipose cells

The stomach is the recipient of ingested food. It continues digestion after mastication and the addition of salivary amylase to the meal. The stomach has the ability to receive a meal (receptive adaptation), and the volume it may accommodate is contingent upon the composition of the meal and the time it takes to ingest it. Mindful eating, with a person chewing each bite thoroughly, taking the time to enjoy the taste and texture of food, leads to weight loss by prolonging the ingestion time and allowing the central nervous system to register fullness. Restriction of the receptive volume of the stomach is a well-defined means to decrease caloric intake, and has led to the creation of several procedures to accomplish this.

Intragastric Balloons

Intragastric balloons occupy volume within the lumen of the stomach. They restrict the gastric volume available for nutrient intake. In 2015 the FDA approved two intragastric balloon systems for the treatment of obesity. Both balloons are currently indicated for patients with a body mass index (BMI) of 30 to 40 kg/m2. Both balloons are filled with saline.

The first type of balloon is designed for 6 months of use. Trials are under way to extend its use to 12 months. It is a single silicone balloon that is filled with 400 to 700 mL of saline. Blue dye is put into the saline as a warning that a balloon may have leaked. The blue dye enters the circulation, is filtered by the kidneys and is excreted into the urine. Blue dye mixes with yellow bile pigments and, as a result, the appearance of green urine signals balloon leakage.

The second type of balloons is endoscopically placed and retrieved. Retrieval has to be done under general anesthesia to protect the airway and prevent any possible aspiration. About 15% of patients have early removal because they are not able to tolerate the balloons.

In February 2017 the FDA communicated potential risks of fluid-filled intragastric balloons. Both types of balloon are associated with overinflation and pancreatitis. The FDA mandated a post-approval study and in April 2020 published its findings. Balloon hyperinflation was present in 6 out of 258 patients (2.3%) with the first type. There were no hyperinflation reports with the second type. There were 2 out of 159 (1.3%) patients diagnosed with acute pancreatitis with the first type, while pancreatitis did not occur with the second type.

A third type of balloons was approved by the FDA on September 8, 2016. They are smaller polyethylene-blend balloons designed to be swallowed in a capsule, so endoscopy is not needed for placement. A patient may ingest up to three individual balloons. The second balloon is usually placed about two weeks after the first one. A third balloon may be added between the 9th and 12th weeks. Each balloon is filled with nitrogen mix gas. Each balloon reaches a volume of 250 mL. The length of use is 6 months. Extraction under general anesthesia is done with endoscopy.

The FDA has allowed intragastric balloons to remain in the market as a treatment option for obesity. This therapy is generally not covered by the third-party payer system. Both lack of coverage and potential for complications have limited their use.

Percutaneous Gastrostomy Device

The FDA approved the percutaneous gastronomy device system for the long-term treatment of patients with obesity on June 14, 2016. It is intended for use in conjunction with ongoing lifestyle therapy, and requires continuous medical monitoring.

The device is a percutaneous gastrostomy tube pump. It allows a person to remove part of an ingested meal through an external skin port 20–30 min after eating. This can achieve up to 49% of excess weight loss. It is a long-term device and is kept for about 1 year unless desired by the patient to maintain it for the long term. The long-term complications are nausea or vomiting.

Spherical Silicone Bulbs

Spherical silicone bulbs were approved by the FDA on April 16, 2019. They consists of a spherical silicone bulb attached to a smaller silicone bulb by a flexible tether. This device is delivered endoscopically through an overtube. It is removed endoscopically. It remains in a transpyloric position with the smaller bulb entering the duodenum by peristalsis. The larger bulb resides in the antrum of the stomach, intermittently occluding the pylorus. Although the FDA classified this as a gastric balloon system, it is different because of the transpyloric component.

The ENDObesity II study was completed in December 2017. It included results on 164 patients who completed the trial and 79 control patients. With the first group, there was 9.5% of total body weight lost, compared to 2.8% in the control group. In this trial, 67% of patients in the first group achieved more than 5% total body weight loss at 12 months. There were serious adverse events in this trial, including three patients with new cholelithiasis and one patient with esophageal rupture and pneumothorax. Nausea, upper abdominal pain, vomiting, dyspepsia, abdominal distention, gastroesophageal reflux, erosive gastritis and gastric ulcer occurred frequently.

Experimental Procedures

The incisionless anastomosis system involves passing an endoscope and using specialized instrumentation to create a full-thickness serosa to serosa plication. The Primary Obesity Surgery Endoluminal (POSE) procedure results in the endoscopic equivalent of a gastric sleeve procedure. The gastric fundus is brought down to the gastroesophageal junction by placing 8-9 plications in the gastric fundus. Further plications are placed in the distal body of the stomach. In a trial, the excess weight loss was 4.95% in 12 months.

Botulinum toxin A is a selective acetylcholine blocker. In theory, it should help weight loss by delaying gastric emptying and the induction of satiety through inhibition of vagal-mediated intestinal contractions. A recent meta-analysis of eight studies did not document benefit, so this remains an area of potential future development.

An endoluminal vertical gastroplasty device was approved by the FDA for development in 2015. This remains investigational, but is a safe and efficacious procedure.

Two companies have developed endoluminal sleeves to create malabsorption of nutrients, bypassing the digestive process. One sleeve is anchored at the esophagogastric junction. The other sleeve at the gastroduodenal junction. Development of both endoluminal sleeves has come to an end, since there were serious problems with the attachments needed to anchor the devices. Perforations causing intrathoracic or intra-abdominal infections significantly detracted from the significant weight loss achieved by these devices.

The FDA approved a vagal blockade system on January 14, 2015. The ReCharge Trial, published in 2016, produced two-year outcomes in data for vagal nerve blockade to treat obesity. At the two year mark 76% of patients implanted with the device remained in the trial. In this patient group there was 21% of excess weight loss, with 58% of participants reaching more than 5% total weight loss. 34% of the patients achieved a total body weight loss of 10% or more. Heartburn and implant site pain were the two most reported adverse events.

Splanchnic nerve stimulation has also been studied for weight loss. There have been early documented improvements in metabolic parameters with splanchnic nerve stimulation, but these were not associated with significant weight loss. As a result, planchnic nerve stimulation for weight loss was abandoned as a concept.

Deep transcranial magnetic stimulation is another emerging treatment for obesity. Repetitive transcranial magnetic stimulation of the prefrontal cortex and insula bilaterally leads to weight loss, but this potential treatment is still in the very early stages of development.

Commentary

Next Article:
Chapter 5: A Look at Disparities in Coverage and Reimbursement
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