Current status of endoluminal bariatric procedures for primary and revision indications.

Endoscopic bariatric procedures are gaining traction as possible treatment modalities for obesity. A major reason for its intuitive appeal is the fact that endoluminal obesity therapy represents a much-needed minimally-invasive treatment option that is currently lacking in the management strategy of this worsening epidemic. For example, treatment of coronary artery disease spans a continuum, with cardiac stenting representing a point of intervention between medications/lifestyle changes and cardiac surgery. Similarly, for treatment of degenerative joint disease, arthroscopic surgery has an important role between medication/lifestyle changes and joint replacement surgery. By comparison, in the treatment of obesity, there is currently a glaring absence of minimally invasive options between medications / lifestyle changes, which have limited efficacy, and conventional bariatric surgery, which exhibits a not insignificant morbidity and mortality profile that causes many to avoid seeking treatment. Endoscopic bariatric procedures can potentially satisfy the need for a minimally-invasive option in one or more different capacities. For example, they may be used as a (1) early-intervention to provide weight loss or weight stabilization in early-stage obese patients who do not yet qualify for traditional bariatric surgery. Alternatively, they could be used as a (2) bridge-to-surgery to reduce operative risk for various bariatric and non-bariatric surgeries. Endoscopic bariatric procedures could also be used as a (3) primary metabolic treatment to address comorbid illnesses such as diabetes. Furthermore, they could be used as a (4) primary bariatric treatment in the traditional surgical population, with the efficacy matching the specific device risk profile. Finally, they could be used as (5) revisional treatment for patients requiring repair following traditional bariatric surgery.i [TABLE 1] TABLE 1 Bariatric Endoscopy—Different Points of Intervention i This chapter will focus its discussion on the various endoscopic devices and procedures that pertain to the last two points of intervention—primary and revisional treatments. However, it is important to keep in mind that many of these devices may also be applicable to one or more of the other three categories. This depends on various device-specific attributes; such as, safety, removability or reversibility, and effect on co-morbid illness. For example, intragastric balloons may be best applied as a bridge therapy because they require removal after 6 months, while endoscopic suturing may have more wide-ranging applications as a primary treatment, revisional treatment, early intervention, or bridge-to-surgery depending on how the suturing instrument is used. Another example may include endoscopic sleeves that could be applied as both primary metabolic therapy and bridge-to-surgery given the fact they currently require removal and achieve significant metabolic endpoints. This review will largely focus on the primary and revisional applications for specific devices, as the current literature is concentrated in these areas. Study results pertaining to applications in (1) early intervention, (2) bridge-to-surgery, and (3) primary metabolic categories will be highlighted where available. Devices that are currently in human use will be preferentially discussed, followed by references to devices that may see clinical use in the near future. [TABLE 2] TABLE 2 Procedures/Devices – Primary, Revisional, and Future Directions PRIMARY TREATMENT Intragastric Balloons Intragastric balloons have been in use since 1982ii as a space-occupying device to induce a sense of satiety, and they represent the most frequently placed endoscopic device to date. The BioEnterics Intragastric Balloon (BIB, Allergan, Irvine, CA) has been the most extensively studied of the intragastric balloons. [FIGURE 1] The BIB is designed as a sphere to hold 400 to 800 mL of saline, and they require removal after 6 months. They are currently in use worldwide, although they are not yet available in the United States. This is in part due to a number of complications and premature balloon deflation associated mainly with the predecessor Garren-Edwards Gastric Bubble (GEGB). FIGURE 1 BioEnterics Intragastric Balloon (BIB, Allergan, Irvine, CA) (Permission to reuse image pending with Singapore Medical Journal) Studies have demonstrated weight loss in the short-term and mid-term ranges, but long-term weight loss, especially following balloon removal, has been equivocal. Genco, et al retrospectively reviewed 2,515 Italian patients and showed a 6 month excess weight loss of 33.9% ± 18.7.iii However, in a randomized controlled trial comparing balloon treatment versus sham over a 3-month period in 43 patients (mean BMI of 43.3 kg/m2), Mathus-Vliegen et al found no statistical difference.iv Interestingly, after excluding 8 patients who either had not met the 3-month weight loss goal (n=5) or did not tolerate the balloon (n=3), the remaining balloon patients (n=12) exhibited a mean weight loss of 21.3 kg (%EWL of 17.1%) after 12 months. Following balloon removal at 12 months, these patients had still maintained weight loss of 12.6 kg (9.9%) at the end of the second, balloon-free year (with nutrition and physician counseling). In sum, these data suggested that in patients who tolerate therapy, balloon treatment could result in substantial 1-year weight loss, and the greater part of that weight loss could be maintained during a second, balloon-free year. In another prospective study examining long-term outcomes after BIB placement, 100 consecutive morbidly-obese patients were enrolled to 6 months of BIB therapy with no structured weight maintenance program following balloon removal.v 97% of patients completed a mean final follow-up of 4.8 years. After 6 months, 63% of patients had ≥10% baseline weight loss. At final follow-up, only 28% were able to maintain this. At that time, 35 patients had undergone bariatric surgery and 34 patients had no significant weight change from baseline. These findings suggested that balloon implantation may be helpful in a minority of patients for long-term weight loss without a structured weight maintenance program. Intragastric balloons have also been used in the super morbidly obese population as a bridge to conventional bariatric surgery. In one study, a BIB was placed in 26 high-risk super-obese patients with a mean BMI of 65.3 kg/m2 (+/− 9.8) and mean 4.33 +/− 1.12 severe comorbidities.vi Endoscopic placement was uneventful in all patients. However, one patient died from cardiac arrest following aspiration on the first post-insertion day. The mean weight loss was 28.5 +/− 19.6kg after the balloon was removed at 6 months. The mean reduction in comorbidity status was 4.33 to 2.23. Twenty patients underwent primary bariatric surgery the day after BIB removal, and two patients were rejected because of inadequate weight loss. Intragastric balloons are designed for 6-month deployment, but recent studies suggest that repeated treatment may sustain weight loss at least to 1 year. In a prospective, nonrandomized multicenter study, patients with repeat treatment had greater weight loss than single-treatment patients at 1 year (12.0 kg versus 6.0 kg; 40.9% versus 20.8% EWL; p=0.008) but this difference became dampened by the 3 year mark (less than 2 kg difference).vii In summary, intragastric balloons may represent a potential option for patients unwilling to undergo bariatric surgery or as a potential bridge to bariatric surgery with an eye towards reducing perioperative risk.