Endoluminal therapy for weight loss delivered by flexible endoscopy has had appeal for nearly 20 years. The continued growth in the global prevalence of obesity makes the need for new and better treatment options more critical than ever.
Results from the landmark Multicenter ESG Randomized Interventional Trial (MERIT), recently presented at Digestive Disease Week 2022, suggest endoscopic sleeve gastroplasty (ESG) is one such treatment option. But how did we arrive at this place where endoscopic bariatric therapy is positioned to play a leading role in the treatment of obesity?
Early ‘Remodeling’ Efforts
In 2002, the potential for endoluminal suturing had considerable appeal to many endoscopists with the emergence of flexible endoscopic suturing devices, such as the Bard EndoCinch and Wilson Cook Medical suturing systems, that were aimed at preventing gastroesophageal reflux. Soon thereafter, efforts were underway to remodel the stomach to effect weight loss via a restrictive reconfiguration.
Remodeling experiences were reported in 2008 by Fogel and colleagues in Gastrointestinal Endoscopy and in 2010 by Brethauer and colleagues in Surgery for Obesity and Related Diseases. However, the devices and the procedures did not provide durable results for sustained weight loss, and the impact of these anatomic manipulations on gastric physiology was not obvious.
The Mayo Clinic Developmental Endoscopy Unit, under the guidance of Christopher J. Gostout, MD, its founder and world leader in endoscopy, in 2004 initiated a program to remodel the stomach to simulate the Magenstrasse and Mill gastroplasty procedure, which creates a narrow tube along the lesser curve down to but not including the antrum, while isolating the remainder of the stomach. This effort involved the use of a new suturing device called the Eagle Claw, developed by a group of forward-looking endoscopists, the Apollo Group.
The device was unique from earlier devices as it enabled full-thickness sutures to be placed, theoretically providing durable results, but was exceedingly clumsy. The Apollo Group formed Apollo Endosurgery in 2005, anticipating intense involvement creating products to fuel the growth of natural orifice endoluminal surgery. Apollo Endosurgery immediately redesigned the Eagle Claw creating the OverStitch (OS) device, a significantly more user-friendly, effective full-thickness suturing device that is used today across a wide variety of procedures and geographies.
Innovation at Mayo Clinic
In 2012, the Mayo Clinic initiated a pilot clinical study using the OS device to fashion a gastroplasty along the greater curve of the stomach from the incisura to the cardia. Unlike the original Magenstrasse and Mill gastroplasty, the Mayo gastroplasty drew the anterior and posterior walls and greater curve of the stomach together in individual plications or imbrications marching up from the distal stomach to the proximal stomach. A second overlying layer of retention sutures involving the anterior and posterior walls was created to bolster the gastroplasty.
Named endoscopic sleeve gastroplasty, the success of the procedure was reported in 2013 and immediately captured attention worldwide. Others helped modify the ESG procedure to be more efficiently performed and better distribute the tissue load over the length of each suture. The current gastroplasty sleeve concentrically reduces the volume of the stomach by an estimated 80% while also reducing the length of the stomach with a sleeve lumen of approximately 20 mm diameter, creating a remodeled stomach shaped like a funnel. These anatomic changes in the stomach result in physiological changes in appetite and metabolic pathways conducive to weight loss and improvement in metabolic parameters.
Since then, ESG has become a leading endoluminal weight loss procedure worldwide with more than 15,000 procedures performed and supported by numerous publications, including patient follow-up of 5 years in some reports. ESG epicenters have evolved in Spain, Italy, Brazil, Australia, the Middle East and Thailand. Although interest in the West has primarily been in weight loss strategies for the obese, in the Asian Pacific there is additional attention aimed at controlling type 2 diabetes in the overweight population.
Publications have reported a safety margin significantly better than can be achieved with laparoscopic sleeve gastrectomy. Expected weight loss is above 15% total body weight loss, and studies have consistently reported clinical improvement in control of hypertension, hyperlipidemia, type 2 diabetes and metabolic syndrome.
Landmark Study Sets the Stage
The only prospective study to date is MERIT, which was initiated in 2017 by the Mayo Clinic and involved nine sites, academic and community-based, with gastroenterologist and bariatric surgeon investigators who had a range of experiences with the procedure. Erik Wilson, MD, and I served as co-principal investigators. In the study, 209 patients were randomized to ESG or lifestyle interventions with crossover of the lifestyle intervention group to ESG if weight loss milestones were not achieved.
Follow-up of the primary ESG group was carried through to 2 years with 1 year follow-up for the crossover group. Total body weight loss was 13.6% in the ESG group vs. 0.8% in the lifestyle group.
There was improvement in at least one comorbidity in slightly over 80% of patients. Serious adverse events occurred in three patients and did not result in intensive care, surgery or mortality. The MERIT study results proved the effectiveness of the procedure and its durability and safety. The study outcomes have been center stage in major medical meetings worldwide.
ESG may also be an ideal procedure to be combined with pharmacotherapy for greater weight loss, perhaps rivaling sleeve gastrectomy. The durability of ESG raises realistic interest in using the procedure as a primary treatment for NASH, which has become the dominant chronic liver disease leading to transplantation and is without any effective drug therapy. Moreover, the procedure can serve as a bridge to bariatric surgery among the super-obese.
ESG has opened an opportunity for providers and their patients who are struggling with obesity, many of whom have tried and failed to lose weight through changes to diet and lifestyle and are not interested in or candidates for bariatric surgery. We now have a procedure that is not only less invasive but also safe, effective and, importantly, organ-sparing. As gastroenterologists, we now have the opportunity to take a leadership role, in collaboration with our surgeon colleagues, to bring endoscopic bariatric treatments into the mainstream of patient care.
Credits and article source: https://www.healio.com/news/gastroenterology/20220714/bariatric-endoscopy-opens-leadership-role-to-gis-for-obesity-management
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Barham K. Abu Dayyeh, MD, MPH, is director of advanced endoscopy and professor of medicine in the department of gastroenterology and hepatology at the Mayo Clinic in Rochester, Minnesota.