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SAN DIEGO -- The 2016 edition of Digestive Disease Week featured many presentations on bariatric procedures -- surgical and otherwise -- covering novel technologies and approaches. Here we review a few selected by the meeting's organizers as especially noteworthy.

Swallowable Balloons

Gastric balloon products are currently available for bariatric treatment, but these require an endoscopic procedure for placement and filling, and pain and discomfort are frequently reported.

A company called Obalon has developed an alternative approach in which the deflated balloon is packed into a capsule, with a long, thin catheter attached. The patient swallows the capsule -- which measures about 3 cm in length and 1 cm in diameter -- which then dissolves in the stomach, allowing the balloon to be inflated with nitrogen gas through the removable catheter. No endoscopy is required for placement, although the balloons are intended to be removed after several months, which does require an endoscopic procedure.

The theory, of course, is that the balloons prevent patients from eating large amounts of food. With training and adherence to an appropriate diet, substantial and rapid weight loss is typical.

Obalon sponsored a randomized pivotal trial aimed at winning U.S. approval, reported here by , of Washington University in St. Louis. It recruited participants with body mass index (BMI) values of 30-40 kg/m² were asked to swallow up to three capsules, with controls receiving a sugar-filled sham. Some 419 patients were initially enrolled; Sullivan reported data on 387 who swallowed at least one capsule. About 95% of these patients swallowed two or three capsules, which constituted the per-protocol population. Participants were asked to swallow one capsule each month during the trial's first 3 months.

The primary outcome measure was percentage of total body weight lost after 6 months, at which point the balloons were explanted. Among the 366 patients in the per-protocol analysis, mean weight loss reached 6.81% in the active-device group compared with 3.59% in the sham group (P=0.03), Sullivan reported. Some 64% of patients with two or three balloons lost at least 5% of body weight, versus 32% of controls. Metabolic parameters including systolic blood pressure, fasting glucose, and blood lipids all showed significant improvements from baseline in the per-protocol balloon patients that were not seen in controls.

There were no severe adverse events among balloon recipients and only one rated as serious -- and that one, a gastric ulcer, occurred in a patient who began taking nonsteroidal anti-inflammatory drugs (NSAIDs) in violation of the study protocol, Sullivan said. Mild to moderate abdominal cramping and nausea were common, however, reported by 90% of patients.

Still, Sullivan said, the overall adverse effect profile appeared better than has been reported for fluid-filled, endoscopically placed gastric balloons. Average time to swallow the capsule, inflate the balloon, and withdraw the catheter was about 15 minutes.

Since the balloons are intended to be removed after a period of months, and long-term follow-up has not been completed, the durability of response is still uncertain, Sullivan told 乌鸦传媒. She noted that patients appeared to be continuing to lose weight in the final weeks before explantation, suggesting that greater weight loss could be achieved with longer dwell times. On the other hand, spontaneous deflation is inevitable and is considered an adverse event. Sullivan also pointed out that, since the devices are relatively easy to place, they can be reinserted if weight regain occurs.

One way in which the balloon therapy might be further optimized, she added, is with "a more specific lifestyle therapy." Patients in both arms of the trial were given the same, standard diet-and-exercise counseling.

The Obalon balloons are currently available in several European countries and Mexico.

Duodenal-Jejunal Sleeve

Marek Benes, MD, of in Prague, presented results of a 70-patient study conducted in the Czech Republic of a duodenal-jejunal sleeve product tradenamed EndoBarrier, manufactured by GI Dynamics of Lexington, Mass. It is available commercially in a number of European countries, Chile, and Australia, but is not yet approved in the U.S.

It's a clear plastic sleeve 60 cm in length, placed endoscopically and anchored in the duodenum from which it extends into the small intestine. It performs a similar function to the "Roux" bypass in conventional Roux-en-Y surgery, in that food particles pass from the stomach into the small intestine without making contact with the jejunum. This is believed to be at the root of the metabolic effects seen with bypass surgery, such as the almost immediate improvement in blood glucose and other diabetic parameters seen after Roux-en-Y procedures. Benes said mean time to implant the device in the study was 17 minutes (range 7-66 min).

Patients in the study were randomized 45:25 to receive the sleeve or a control intervention. The latter did not include a sham procedure, but instead was counseling and supportive care delivered by the same multidisciplinary team (dietitian, psychologist, diabetologist, and gastroenterologist) who provided aftercare to the sleeve recipients. Benes emphasized that post-placement care is crucial with the implant, since failure to follow diet and activity recommendations can undermine its effectiveness.

At baseline, mean BMI was 42 kg/m² in the sleeve group and 40 kg/m² among controls. Mean age was about 51 and approximately 60% were men. Mean HbA1c value was 8.8% and 8.6% in the sleeve group and controls, respectively.

At 10 months following device placement, results were as follows (all P<0.05):

• Change in BMI: -8 points with device, -3 points in controls
• Excess weight loss: 43% with device, 12% in controls
• Change in HbA1c: -2.5 percentage points with device, -1.0 point in controls
• Change in waist circumference: -23 cm with device, -6 cm in controls

Abdominal pain was common with the device, but patients predominantly rated it as mild and most reports of pain were in the first month after implantation. No devices were explanted because of pain, Benes said. Six patients of the 45 device recipients did have them removed for other reasons: one because it would interfere with a scheduled ERCP procedure, and five because of bleeding, device migration, or both. Explants were uncomplicated and took about the same time as did the implants.

One interesting finding, Benes said, was that physically larger patients tended to respond less strongly to the device. He said it may be that its 60-cm length is too short for very tall and very heavy patients for it to be fully effective.

He also noted that the anchor point for the device appeared to play a role in patients' pain complaints, with more pain associated with distal placement in the duodenum.

Prospects for the EndoBarrier are still somewhat uncertain, after a last year when it was discovered that seven patients had developed liver abscesses following placement of the device in about 200 patients, for a rate of approximately 3.5%.

Benes said no liver abscesses were seen in his study. He said he suspected patient selection was to blame for the problem in the U.S. trial: it had a high proportion of participants with low socioeconomic status and who used tobacco and/or alcohol, which put them at risk for infections.

GI Dynamics said its experience elsewhere in the world where the EndoBarrier is marketed shows a 0.73% incidence of liver abscess with some 3,000 units shipped. The firm said it expected to conduct a new trial in the U.S. aimed at winning FDA approval.

Novel Gastric Stapler

Also reported at DDW was a trial of a novel gastric stapler, deployed transorally to reduce stomach volume, thereby achieving the same effects as sleeve gastrectomy in a less invasive way.

The device, developed by Boston Scientific, is operated endoscopically. It uses suction, a mechanical pinching mechanism, and a stapler to create plications in the gastric wall.

Results in 69 patients, treated at six centers in four countries, were presented by , of Laval University in Quebec City. Mean BMI was 38 kg/m². Most patients were women and the mean age was 40.

It's a more laborious procedure than the device implants: operative time averaged over 100 minutes. An average of nine plications were created in each patient. The operation of the stapler itself was quite safe, Biertho told 乌鸦传媒, with no serious adverse events seen in more than 600 firings of the stapling mechanism.

Adverse events overall were about what would be expected in a gastric reduction procedure. Pain, nausea, and vomiting were seen in roughly 35%-45% of patients.

Loss of excess weight appeared to peak at 1 year after the procedure, at which point it had reached 35% in evaluable patients. By year 2, however, excess weight loss relative to baseline had retreated to 21%. Biertho said it appears that patients' metabolism and/or eating habits may evolve after the initial period of weight loss to compensate for the reduced stomach volume.

A controlled trial with longer follow-up will be needed to understand whether the procedure gives durable results, he said. He also noted that there was a in the current study: it had been commenced by a company called BaroSense that ceased operations partway through the trial. At that point, some investigators stopped following up with patients. Boston Scientific then acquired rights to the device and began funding renewed follow-up in the original participants, but mid-term results for many patients were irretrievably lost.