Obesity affects more than one third of adults in the United States and is associated with increased morbidity, mortality, and health care costs compared with normal weight adults. Current therapies include medical management consisting of therapeutic lifestyle change and pharmacotherapy, which has limited effectiveness, and bariatric surgery, which is currently the most effective therapy, but is limited by complications, long-term weight regain, and limited access. Endoscopic therapies are currently under investigation to treat weight regain after bariatric surgery and as a primary treatment for obesity, addressing the current gap in the treatment of obesity.
Key Points
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Obesity affects more than one third of adults in the United States and is associated with increased morbidity, mortality, and health care costs.
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Current treatment options include medical management with therapeutic lifestyle change and pharmacotherapy, as well as bariatric surgery; however, these treatments have limitations.
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Endoscopic therapies are emerging as potential tools to address the limitations of the current obesity therapies.
Unfortunately, current treatment options for obesity are limited. Therapeutic lifestyle change (TLC) consisting of diet, exercise, and behavior modification results in up to 10% short-term weight loss, but 5% or less weight loss in the long term. Weight loss medications increase weight loss by 3% to 5% over placebo and are more likely to result in 10% weight loss in patients than TLC alone ; however, medical therapy must be continued long term to maintain any weight loss achieved with the medication. Bariatric surgery has been shown to be superior to TLC and pharmacotherapy for weight loss and weight maintenance, and remains the most effective treatment option available for obesity. Although short-term costs for the surgery and postoperative complications are high, long-term cost–benefit analyses favor bariatric surgery over medical management of obesity. Minor postoperative complications occur frequently, but serious complications occur in 5% or fewer of post bariatric surgery patients and the mortality rate is low. However, 2 issues continue to plague bariatric surgery: Failure of weight loss or weight regain and limited access to surgery. Although the number of bariatric procedures performed per year has increased from 9189 in 1993 to 124,838 in 2008, this only represents approximately 1% of obese persons who qualify for a bariatric surgical procedure. Endoscopic bariatric procedures have emerged as potential options that not only address both of these issues, but also have reduced associated morbidity and mortality as well.
Endoscopic therapy for weight loss failure
Weight regain has been reported in long-term studies, capturing patient weight 10 years or more after the original bariatric surgical procedure. In the Swedish Obesity Study, 8.8% of Roux-en-Y gastric bypass (RYGB) patients and 25% of adjustable gastric banding patients maintained less than 5% of their weight loss at 10 years. Similar rates of weight loss failure at 10 or more years of follow-up, as defined by end BMI compared with starting BMI, were seen in patients after RYGB and Bilioopancreatic Diversion (BPD), but were higher in patients with higher preoperative BMI.
Although multiple factors likely play a role in weight regain, the factors that may be treated by endoscopists include gastro-gastric fistulas, stoma dilation, and pouch dilation. Some controversy exists regarding the role of stoma and pouch dilation in weight regain. Multiple early studies did not show a correlation between pouch diameter and weight loss ; however, some early studies did show a correlation, even in the setting of extensive behavior modification therapy. More recently, both pouch size and stoma diameter have been shown to be significantly correlated with weight loss failure or weight regain in both univariate and multivariate analyses, but not in all studies. Heneghan and colleagues found small, but significant differences pouch length (5.0 ± 2.4 vs 5.8 ± 2.6 cm; P = .005) and stoma diameter (2.1 ± 0.8 vs 2.5 ± 1.0 cm; P <.001) in the control (no weight regain) compared with weight regain groups, respectively. Failure to lose weight or weight regain has been treated by bariatric surgical revision with mixed outcomes. Weight loss has been demonstrated, but the surgical complication rates are higher than with the index procedure. Given the risk of revisional surgery, endoscopic approaches including the use of sclerosants to decrease stoma diameter, as well as decreasing stoma and pouch size with suturing, tissue plication, or clips have been investigated as safer options compared with surgery.
Sclerotherapy of dilated gastrojejunostomies was first described in 2003, and since then a number of series using sclerotherapy for dilated stomas have been published with weight loss or weight stabilization in 50% to 91.6% of patients at 1 year. The largest of these series included 231 patients with weight regain and an average baseline gastrojejunostomy stoma diameter that was 19 mm. These patients were treated with an average of 2 sclerotherapy sessions and 16 mL of sodium morrhuate injected at each session. The average weight loss 6 months after sclerotherapy was 18% of the weight that had been regained, and 76% of patients lost more weight or maintained their 6-month weight loss at 12 months. Complications included bleeding (2.4% immediate and 0.2% delayed), abdominal pain requiring admission (0.5%), and small ulcers on repeat endoscopy (1%). Baseline stoma diameter was not a predictor of response to sclerotherapy.
The Endocinch Suturing System (C.R. BARD Inc, Murray Hill, NJ, USA) was piloted by Thompson and colleagues in 2006. The authors used a technique of mucosal ablation with argon plasma coagulation followed by placement of 2 sutures on average and then tightening the sutures to form tissue plications. The average stoma diameter was reduced to 10 mm (68% reduction), and patients had an average excess weight loss of 23.4%. This device has also been studied in a randomized, double-blinded, sham-controlled, multicenter trial of 77 patients. Patients included in the study had baseline stoma diameters of more than 20 mm. The authors achieved a gastrojejunostomy of 10 mm or less in 89% of patients randomized to the treatment arm with an average number of 4 sutures placed. A trend was seen in the intention-to-treat analysis with more weight loss in the treatment group compared with the control group (4.2 ± 5.4% and 1.9 ± 5.2%; P = .066) at 6 months.
The Incisionless Operating Platform (USGI Medical, San Clemente, CA, USA) is a tissue plication system that places expandable tissue anchors to hold tissue together. Two small pilot studies of decreasing stoma diameter and pouch length in patients with weight regain after RYGB demonstrated short-term weight loss of 7.8 to 8.8 kg at 3 months. Data from a multicenter registry of 116 patients reported 32% (6.5 ± 6.5 kg) of the regained weight was lost at 6 months with stoma diameter reduced by 50% to 11.5 mm, and pouch length reduced by 44% to 3.3 cm. At 12 months post-procedure, 73 of 112 subjects with successful procedures had a total weight loss of 5.9 ± 1.1 kg.
The StomaphyX device (EndoGastric Solutions Inc, Redmond, WA, USA) is a tissue plication device that uses polypropylene H-fasteners to approximate serosal surfaces. This device was first used to treat weight regain with 39 patients who were at least 2 years out from RYGB and had gained at least 10% of their lowest weight. Excess body weight loss was 19.5% 12 months post-procedure; however, only 6 of 39 patients returned for the 12-month follow-up. Another study of 64 patients used an average of 23 H-fasteners and reported a 33% decrease in gastric pouch length and the stoma was reduced from 22 to 9 mm. The average weight loss was 7.3 kg, but the mean follow-up was only 5.8 months. Two other small studies have shown weight loss after endoscopic revision with StomaphyX.
Over-The-Scope-Clips (Ovesco, Tubingen, Germany) have also been used to reduce stoma diameter to treat weight regain after bariatric surgery. One study reported 94 subjects whose stoma diameter was reduced from 35 to 8 mm with placement of up to 2 Over-The-Scope-Clips placed on opposite sides of the stoma. Mean BMI decreased from 32.8 ± 1.9 to 27.4 ± 3.8 kg/m 2 at 12 months; however, 2 patients requiring dilation of the stoma to 12 mm owing to persistent dysphagia.
Although these case series are encouraging, further research in endoscopic therapy of weight regain after bariatric surgery is needed. First, only one endoscopic bariatric revision procedure has been studied in a randomized, double-blind, sham-controlled study, and only a trend was seen toward more weight loss in the treatment group. This may in part be due to either patient selection or the underlying cause for the stoma and pouch dilation, which has yet to be determined. Based on the variability in the pre-endoscopic revision stoma and pouch diameter seen in these cases series as well as the study by Heneghan and colleagues demonstrating statistically different but clinically similar stoma diameter between patients with weight regain and those maintaining their weight loss, it is unclear which patients are most likely to benefit from these procedures. However, given the weight loss seen in many patients and the significantly decreased risks associated with endoscopic stoma and pouch revision compared with surgical revision, endoscopic treatment of weight regain after bariatric surgery remains a promising therapeutic option.
Endoscopic therapy for weight loss failure
Weight regain has been reported in long-term studies, capturing patient weight 10 years or more after the original bariatric surgical procedure. In the Swedish Obesity Study, 8.8% of Roux-en-Y gastric bypass (RYGB) patients and 25% of adjustable gastric banding patients maintained less than 5% of their weight loss at 10 years. Similar rates of weight loss failure at 10 or more years of follow-up, as defined by end BMI compared with starting BMI, were seen in patients after RYGB and Bilioopancreatic Diversion (BPD), but were higher in patients with higher preoperative BMI.
Although multiple factors likely play a role in weight regain, the factors that may be treated by endoscopists include gastro-gastric fistulas, stoma dilation, and pouch dilation. Some controversy exists regarding the role of stoma and pouch dilation in weight regain. Multiple early studies did not show a correlation between pouch diameter and weight loss ; however, some early studies did show a correlation, even in the setting of extensive behavior modification therapy. More recently, both pouch size and stoma diameter have been shown to be significantly correlated with weight loss failure or weight regain in both univariate and multivariate analyses, but not in all studies. Heneghan and colleagues found small, but significant differences pouch length (5.0 ± 2.4 vs 5.8 ± 2.6 cm; P = .005) and stoma diameter (2.1 ± 0.8 vs 2.5 ± 1.0 cm; P <.001) in the control (no weight regain) compared with weight regain groups, respectively. Failure to lose weight or weight regain has been treated by bariatric surgical revision with mixed outcomes. Weight loss has been demonstrated, but the surgical complication rates are higher than with the index procedure. Given the risk of revisional surgery, endoscopic approaches including the use of sclerosants to decrease stoma diameter, as well as decreasing stoma and pouch size with suturing, tissue plication, or clips have been investigated as safer options compared with surgery.
Sclerotherapy of dilated gastrojejunostomies was first described in 2003, and since then a number of series using sclerotherapy for dilated stomas have been published with weight loss or weight stabilization in 50% to 91.6% of patients at 1 year. The largest of these series included 231 patients with weight regain and an average baseline gastrojejunostomy stoma diameter that was 19 mm. These patients were treated with an average of 2 sclerotherapy sessions and 16 mL of sodium morrhuate injected at each session. The average weight loss 6 months after sclerotherapy was 18% of the weight that had been regained, and 76% of patients lost more weight or maintained their 6-month weight loss at 12 months. Complications included bleeding (2.4% immediate and 0.2% delayed), abdominal pain requiring admission (0.5%), and small ulcers on repeat endoscopy (1%). Baseline stoma diameter was not a predictor of response to sclerotherapy.
The Endocinch Suturing System (C.R. BARD Inc, Murray Hill, NJ, USA) was piloted by Thompson and colleagues in 2006. The authors used a technique of mucosal ablation with argon plasma coagulation followed by placement of 2 sutures on average and then tightening the sutures to form tissue plications. The average stoma diameter was reduced to 10 mm (68% reduction), and patients had an average excess weight loss of 23.4%. This device has also been studied in a randomized, double-blinded, sham-controlled, multicenter trial of 77 patients. Patients included in the study had baseline stoma diameters of more than 20 mm. The authors achieved a gastrojejunostomy of 10 mm or less in 89% of patients randomized to the treatment arm with an average number of 4 sutures placed. A trend was seen in the intention-to-treat analysis with more weight loss in the treatment group compared with the control group (4.2 ± 5.4% and 1.9 ± 5.2%; P = .066) at 6 months.
The Incisionless Operating Platform (USGI Medical, San Clemente, CA, USA) is a tissue plication system that places expandable tissue anchors to hold tissue together. Two small pilot studies of decreasing stoma diameter and pouch length in patients with weight regain after RYGB demonstrated short-term weight loss of 7.8 to 8.8 kg at 3 months. Data from a multicenter registry of 116 patients reported 32% (6.5 ± 6.5 kg) of the regained weight was lost at 6 months with stoma diameter reduced by 50% to 11.5 mm, and pouch length reduced by 44% to 3.3 cm. At 12 months post-procedure, 73 of 112 subjects with successful procedures had a total weight loss of 5.9 ± 1.1 kg.
The StomaphyX device (EndoGastric Solutions Inc, Redmond, WA, USA) is a tissue plication device that uses polypropylene H-fasteners to approximate serosal surfaces. This device was first used to treat weight regain with 39 patients who were at least 2 years out from RYGB and had gained at least 10% of their lowest weight. Excess body weight loss was 19.5% 12 months post-procedure; however, only 6 of 39 patients returned for the 12-month follow-up. Another study of 64 patients used an average of 23 H-fasteners and reported a 33% decrease in gastric pouch length and the stoma was reduced from 22 to 9 mm. The average weight loss was 7.3 kg, but the mean follow-up was only 5.8 months. Two other small studies have shown weight loss after endoscopic revision with StomaphyX.
Over-The-Scope-Clips (Ovesco, Tubingen, Germany) have also been used to reduce stoma diameter to treat weight regain after bariatric surgery. One study reported 94 subjects whose stoma diameter was reduced from 35 to 8 mm with placement of up to 2 Over-The-Scope-Clips placed on opposite sides of the stoma. Mean BMI decreased from 32.8 ± 1.9 to 27.4 ± 3.8 kg/m 2 at 12 months; however, 2 patients requiring dilation of the stoma to 12 mm owing to persistent dysphagia.
Although these case series are encouraging, further research in endoscopic therapy of weight regain after bariatric surgery is needed. First, only one endoscopic bariatric revision procedure has been studied in a randomized, double-blind, sham-controlled study, and only a trend was seen toward more weight loss in the treatment group. This may in part be due to either patient selection or the underlying cause for the stoma and pouch dilation, which has yet to be determined. Based on the variability in the pre-endoscopic revision stoma and pouch diameter seen in these cases series as well as the study by Heneghan and colleagues demonstrating statistically different but clinically similar stoma diameter between patients with weight regain and those maintaining their weight loss, it is unclear which patients are most likely to benefit from these procedures. However, given the weight loss seen in many patients and the significantly decreased risks associated with endoscopic stoma and pouch revision compared with surgical revision, endoscopic treatment of weight regain after bariatric surgery remains a promising therapeutic option.
Primary endoscopic bariatric therapy
Endoscopic bariatric therapy (EBT) is still in its infancy, and currently no EBT devices have been approved for use in the United States; however, there are many advantages to EBT compared with traditional bariatric surgery. First, although weight loss with EBT is likely to be less than most bariatric surgical procedures, EBT is associated with lower complication rates and shorter recovery times than bariatric surgery. Both the lower risk profile and decreased recovery time may increase the number of patients willing to undergo a weight loss procedure. In addition, because most EBT only require conscious sedation, sicker patients who may not be good candidates for surgery may still qualify for endoscopic placement of a device. Further, although bariatric surgery is the most effective therapy for weight loss at the patient level, it is limited by the number of patients who can be treated per year, restricting its effect on obesity treatment at the population level. Owing to both the number of practicing gastroenterologists and the short amount of time required for these procedures compared with bariatric operative procedures, the number of patients who could undergo EBT potentially dwarfs the number of patients who are able to undergo bariatric surgery per year, making more of an impact on obesity at the population level. Multiple devices have been or are currently in the development and testing stages for EBT; however, for the purposes of this review, only technologies that have published data and are still viable are discussed.
Intragastric balloon
The intragastric balloon (IGB) is a device that was designed to occupy space and cause gastric distension with the goal of decreasing food intake. The first IGB device, the Garren-Edwards Gastric Bubble, was approved for use by the US Food and Drug Administration in 1985; however, it was taken off of the market in 1992 owing to both complications (including damage to the gastric mucosa and balloon deflation with subsequent small bowel obstruction) and lack of difference between the device and TLC in sham-controlled trials. These 2 issues were thought to be related to the design of the device itself. First, the device volume was only 220 mL when distended, and evidence suggests that a volume of at least 400 mL is needed for a reduction of food intake, and the device had a cylindrical shape with edges, which damaged the mucosa. In addition, it was made from polyurethane that was too easily deflated. Several new designs including the BioEnterics IGB (BIB; Allergan, Irvine, CA, USA), ReShape Duo (ReShape Medical, San Clemente, CA, USA; Fig. 1 .), the Heliosphere IGB (Helioscopie, Vienne, France), and the Spatz Adjustable Balloon System (Spatz FGIA, Jericho, NY, USA) have been developed and address the issues surrounding the failure of the Garren-Edwards gastric bubble. Although these devices have different designs to decrease balloon rupture and migration, they all have eliminated edges to reduce mucosal damage and have increased device volume to induce an effect on food intake.
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