BB&T Contributing Editor
DALLAS — One can no longer count only the 225,000 bariatric surgery procedures performed annually as being "the bariatric surgery market." As the American obesity epidemic grows, so does the growth in new technologies to address not only the current population of patients seeking surgical assistance, but also those who qualify but never enter a doctor's office for fear of surgery.
Both adjunctive technologies for better patient outcomes using current surgical approaches and a host of less-invasive innovative products that address the obese millions afraid to go under the knife were presented during the 26th annual meeting of the American Society of Metabolic and Bariatric Surgery (Gainesville, Florida), held here in the latter part of June.
There was a flurry of activity among the exhibitors to showcase improvements and innovations in technologies that can help the 20 million to 25 million obese Americans.
After closely following the hundreds of thousands of post-bariatric surgery patients, market segmentation within the bariatric surgery space has evolved.
For most morbidly obese patients, the now-standardized surgical procedures will be adequate. However, some patients have more specific needs, which fueled much discussion at this year's meeting. Until recently, the only options for bariatric patients were which type of surgery: gastric bypass, lap-banding, duodenal switch, or the newly revived gastrectomy sleeve, each having its benefits as well as shortcomings.
For the first time, innovative devices now in human clinical trials offer a menu of products from which the surgeon and patients can select. These new devices can be categorized as being more suitable for specific groups of bariatric patients, such as: less-invasive primary weight loss, revisions for weight re-gain, bridge to surgery, metabolic/diabetic surgery, combinations, or what some predict will become cosmetic or elective procedures.
Revision surgery a new market
It is estimated that about 20% (some report up to 50%) of all bariatric surgery patients will experience enough weight re-gain to require a revision procedure. There is controversy as to the reasons why people fail gastric bypass surgery: two suggested theories are enlargement of the stoma at the gastrojejunostomy and dilatation of the gastric pouch.
Because of potential adhesions from the original surgery along with the fact that the patient anatomy has been altered, most surgeons consider an endoluminal approach for revision surgery. Many of the new devices — whether targeting revision surgery or primary — have adopted an endoluminal approach because it is less invasive, lower cost, earlier convalescence, complications are reduced, and eventually they will not need to be performed in an operating room, also driving the cost down.
There are several new companies that fit this bill, most of which are in clinical trials. In a presentation titled "Endoscopic Gastric Pouch Reduction," Dean Mikami, MD, of Ohio State University (Columbus), briefly described several companies' products — both in development and on the market — that can perform endoluminal pouch reductions, often used for revisions (see Table 1).
USGI (San Clemente, California) was the first with its ROSE (Restorative Obesity Surgery Endoluminally) procedure. C.R. Bard's (Murray Hill, New Jersey) Endocinch was originally approved to treat GERD, but many bariatric surgeons are using it off-label as a revision tool for pouch reduction. Endogastric Solutions' (Redmond, Washington) Stomaphyx also was also initially designed to treat GERD but received FDA clearance in 2007 for tissue ligation and approximation and since has been addressing the restorative bariatric surgery market.
Mikami cautioned: "Initial screening of these patients is required to determine which patients will benefit from these procedures. Weight gain is a multi-factorial process; therefore weight loss requires a multi-factorial approach as well. There is a promising future for revisional surgery procedures."
In Table 1, all endoluminal devices that were presented at this meeting are listed, although each has an intended application — some for revisions following weight re-gain, some serve as a primary treatment, and others as a bridge to surgery in order for the patient to reach a weight that is less risky for bariatric surgery. Each company seems to have a strategic target for market entry, but clinical outcomes will determine the appropriateness for use of each product within a specific patient population.
Many speakers at the meeting said they believe that eventually a combination of procedures and surgeries will be selected specifically for each patient, offering a personalized approach depending on their needs. It is interesting to note that most revision surgeries are endoluminal gastric reduction, while endoluminal sleeves often are selected for diabetes control, and space-fillers are frequently used for bridge-to-surgery purposes even though there are no hard-and-fast rules as to which devices work best for different patient needs.
Diabetes control another new market
There is a strong correlation between obesity and diabetes. There are about 19 million Type 2 diabetics in the U.S., of whom 80% are obese. Although there is a genetic factor involved in the development of Type 2 diabetes, the disease is typically instigated by obesity, a lack of exercise, poor diet and a sedentary lifestyle.
Four companies in particular (see Table 2) are developing implants that are delivered endoluminally and are left in place for six months or longer, then retrieved on an outpatient basis using conscious sedation.
Initial clinical studies demonstrate a remission of Type 2 diabetes within a week, much before any significant weight loss is achieved. Gastrointestinal sleeves tend to mimic a surgical procedure but without the permanent alteration of the alimentary tract. Gastrointestinal sleeves offer the quickest diabetic remission.
The Lahey Clinic (Arlington, Massachusetts) is one of four sites studying the Endobarrier by GI Dynamics (Lexington, Massachusetts). About 250 patients have been implanted with an Endobarrier, an impermeable intestinal liner placed in the duodenum that blocks food from mixing with the gut hormones until it passes through the 60 cm sleeve where the food then joins the enzymes and flows through the rest of the digestive tract, mimicking a surgical Roux-en-Y procedure.
All procedures are currently being performed on an outpatient basis under general anesthesia but it is anticipated that the procedure will transition to conscious sedation. Excess weight loss (EWL) was in the mid-20% range, accompanied by a rapid remission of diabetes in Type 2 diabetic patients. Although the implant is explanted at six months, the metabolic effects clearly last beyond the explantation.
GI Dynamics also reported results at this meeting from a clinical trial that studied its new Endobarrier with Flow Restrictor that provides an adjustable restriction at the outlet of the stomach designed to further enhance weight loss. Using this new device, Alex Escalona, MD, of the department of digestive surgery at Pontificia Universidad Cat lica de Chile (Santiago, Chile), presented his results of achieving almost 40% EWL in a 12-week timeframe with 10 patients. These latest data suggest that the combination of the EndoBarrier Gastrointestinal Liner with the EndoBarrier Flow Restrictor could enhance the effectiveness of the liner by nearly doubling the amount of weight loss achieved by using the liner alone.
Valentx (Wilson, Wyoming) also incorporates a restrictive stoma along with a malabsorptive sleeve, while Endosphere (Redwood City, California) has created an implant that delays throughput through the duodenum with the intention of both weight loss and diabetes remission. Gastrx (Marblehead, Massachusetts) also has a sleeve-like implant, so it could be implied that there may be a diabetic remission.
Some key opinion leaders have speculated that with a better understanding of diabetes and how these implants function, it may be feasible in the future to implant these devices in normal weight diabetics to provide remission of their diabetes without dependence on insulin.
In another presentation at this meeting, it was found that the longer and more overweight a diabetic patient went before having bariatric surgery, the less able they were to resolve their diabetes following surgery, suggesting that the mechanism responsible for controlling diabetes had just been "burned out." It also showed that with weight re-gain after surgery there was an accompanying increase in their diabetes, further demonstrating the interdependence of the two diseases and encouraging obese diabetics to seek surgery sooner and to keep the weight off.
Neuromodulation an emerging market
Electrical stimulation to suppress the appetite or create satiety is achieved by laparoscopically placing electrodes in the stomach or on the vagus nerve that are attached to a small pacemaker-like generator (see Table 3). The gastrointestinal tract is not altered, so the mechanism is neither restrictive nor malabsorptive, but rather interferes with hunger signals.
Enteromedics' (St. Paul, Minnesota) VBLOC has been implanted in 300 patients at 15 centers in a double-blind, 60-month clinical trial. Leads are placed on the anterior and posterior vagus nerves and are connected to a neuroregulator that is placed subcutaneously and intermittently blocks the electrical signal. For now, there is an external component worn on a belt; but eventually that will also be placed subcutaneously, eliminating the belt. Two-thirds of the patients had their nueroregulator turned on the first year, while the other third were not turned on. This December, all patients will have theirs turned on and the entire group will be followed for the final year.
Jill Meador, RN, of Virginia Commonwealth University (Richmond), shared the results of an open-label study using VBLOC with no weight management program in place that had a 40% EWL at 18 months with no unanticipated adverse effects. According to Meadow, "We saw reduced caloric intake and suspect outstanding results once the trial is complete." She also mentioned that next the researchers intend to study the effect on diabetes and internalize the entire device so that the patients no longer need to wear a belt.
Space-filling surgical products
Although intragastric balloons are easy to place and serve well as both a bridge to surgery and for treating mild obesity, they may cause nausea and GERD, but with a low complication rate and EWL of 34% at six months on average. Balloons and other space-filling products such as gels and foams that partially fill the stomach often are used as a bridge to surgery for those patients who have too high of a risk profile for bariatric surgery (see Table 4).
A space-filling device is placed through the mouth and left in the stomach for three to six months, allowing patients to feel full and reduce their caloric intake so that they can lose enough weight to be surgery candidates.
This space may also be one of the first to go after the cosmetic, or elective, market that allows patients who do not meet the National Institutes of Health criteria of obesity to obtain the procedure under a doctor's care and self-pay.
An old procedure revived
Sleeve gastrectomy is currently the hottest topic in bariatric treatment. The procedure initially served as a bridge to surgery — actually, part 1 of a two-part procedure — but many of the patients never returned for their bariatric surgery procedure, feeling that they were obtaining adequate weight loss with the sleeve alone. Usually performed laparoscopically, about 70% to 80% of the stomach is removed, leaving a sleeve in place.
The big benefit of this approach is that in addition to the volume reduction, the part of the stomach left is that which produces ghrelin, a hormone that reduces hunger. Many bariatric surgeons can perform sleeve gastrectomy laparoscopically, but it is technically tedious.
Power Medical Interventions (Langhorne, Pennsylvania) has developed a laparoscopic circular stapler that can create the defect, or buttonhole, in the antrum, making the procedure simpler and quicker to perform.
A call for flexible endoscopes in the OR
"Flexible endoscopes, once never considered to be an operating room staple, is now a 'must' in every suite where bariatric surgery is being performed," according to C. Daniel Smith, MD, of the Mayo Clinic (Jacksonville, Florida). "Many of the bariatric patients also have conditions in the esophagus, such as Barrett's, hiatal hernia, GERD, etc. that can compromise the success of the surgery or that the surgery itself can aggravate. By performing a pre-operative endoscopy while in the OR before starting the actual surgery, one can assess the future remnant, check for gastroparesis, biopsy for H. pylori, and look for Barrett's, GERD, hiatal hernia or any condition that may alter the way the surgery and recovery should proceed," he said.
Smith said about 25% of all bariatric patients will test positive for H. pylori and 45% of these will experience nausea post-op compared to only 20% of those patients who tested negative. "One might want to consider eradicating the H. pylori prior to their surgery." In addition to the use of the flexible endoscope prior to beginning the operation, Smith also endorsed the use of flexible endoscopes during the procedure to check for leaks and if found, perform the repair while still in the OR.
In a small study, his research group found that using the standard test for leaks with methylene blue dye, leaks were missed 40% of the time and re-visits to the OR were required. Using direct visualization through an endoscope at the completion of the surgery, only 16% were found, but they could be repaired immediately while still in the OR and there were no leaks found post-op with no re-visits to the OR for leak repair.
"Although the flexible endoscope requires additional skills, possibly an additional person in the OR, along with more time and expense, it is much more accurate in detecting leaks and allows for the repair to be performed immediately with very little additional OR time," Smith said. " For these reasons, it may be becoming the standard of care for bariatric surgery."
New market for existing products
Other "new" markets created by bariatric surgeons for existing products include using stents to prop open strictures or repair leaks following bariatric surgery. Roger de la Torre, MD, of the University of Missouri (Columbia), presented his findings using stents to repair leaks, strictures, and fistulas that developed after bariatric surgery.
He tried both nitinol and polyester stents and had the best success with multiple nitinol stents — usually two long ones — placed overlapping each other. The biggest issue he had initially was that 40% of them migrated, but he found that by using longer nitinol stents that overlapped and allowed tissue in-growth to anchor them, he achieved a 92% success rate.
"Up to 16% of bariatric surgery patients will suffer from post-op nausea and vomiting caused by stromal stenosis," said Daniel Jones, MD, of Beth Israel Deaconess Medical Center (Boston), "Balloon dilatation is a highly effective way to treat patients with this problem."
Another 16% of bariatric surgery recipients will develop anastomotic ulcers — the most common cause of post-op hemorrhage. There are a number of existing surgical tools to address this problem, from delivering thermal energy to applying clips, to injecting fibrin glue, or using a combination of these therapies.
Clumped together, these mini-markets for new uses of existing medical devices can amount to a substantial new area of growth.
Bariatric Surgery Meets Cost Effectiveness Standards
Matthew Hutter, MD, of the department of surgery, at Massachusetts General Hospital (Boston), compared the cost of obesity to the cost of weight loss surgery and found it to be overwhelmingly cost-effective as early as in the first year following surgery. "For laparoscopic surgery, all costs were recouped within the first two years," he said. "Unfortunately, insurers don't pay based on cost-effectiveness. They look at safety, quality, then cost — in that order."
Cost of Obesity
400,000 attributable deaths annually
Twice as many claims for workers compensation
10 times the amount of lost work days
Cost of Weight Loss Surgery
$19,346 average cost
"Medicare looks at a computation called quality adjusted life years (QALY) that includes measuring quality of life, life expectancy, and cost in order to determine payment," Hutter said. " Bariatric surgery falls well below the Medicare threshold of QALY."