Weiss Describes Alternatives to Bariatric Surgery|
Minimally invasive trans-arterial instruments guided by imaging technology may provide a way to block the flow of blood to parts of the stomach that produce the hormone that signals the brain to feel hunger. That, in turn, can help patients lose weight, said Dr. Clifford Weiss at a recent Clinical Center Grand Rounds in Lipsett Amphitheater.
Ten years ago, interventional radiology and treatment of obesity were two concepts “that wouldn’t seem to have gone well together—or at least we wouldn’t have thought that,” said Weiss, associate professor of radiology and radiological science and director of interventional radiology research at Johns Hopkins University School of Medicine. Interventional radiology refers to minimally invasive, image-guided procedures to diagnose and treat disease.
The obesity epidemic is a rapidly growing health care crisis, he said. More than 60 percent of Americans are overweight or obese. Each year, the health care industry spends $210 billion on obesity and obesity-related illnesses. There are more than 100,000 obesity-related deaths each year.
Current treatments for obesity include diet, exercise, medication and, in extreme cases, bariatric surgery, Weiss noted. One type is gastric bypass surgery. It involves reconnecting parts of the stomach and intestines so that food bypasses most of the stomach and the first part of the small intestine.
“There can be serious complications from gastric bypass surgery,” he said. “These are some of the patients you’d least like to operate on. Fat tissue does not heal well.”
One of the effects of bariatric surgery is to alter the production of hormones that signal the brain to feel hungry or full, he explained. Normally, an empty stomach produces ghrelin, a powerful hunger-stimulating hormone. After a person eats, the production of ghrelin decreases and the intestines produce hormones such as GLP-1 and PYY that signal satiety. This combination eases the sensation of hunger, producing an “I’m full” hormonal profile.
Patients who’ve undergone gastric bypass surgery are less hungry than they were before the procedure, partially because their stomachs stop producing as much ghrelin. About 10 years ago, Weiss’s friend and mentor Dr. Aravind Arepally thought he could mimic the effects of the surgery by stopping the blood flow to the fundus, a part of the stomach that produces ghrelin.
The image-guided procedure, known as bariatric arterial embolization, involves the injection of tiny beads through a catheter that’s inserted into the wrist or leg, he said. The beads decrease blood flow in the arteries that feed the fundus.
In the first studies of juvenile pigs, their lab found “the data demonstrates that we can decrease ghrelin and increase GLP-1 with this bariatric procedure.”
Weiss and Arepally then designed the first FDA-approved pilot clinical study—Bariatric Embolization of Arteries for the Treatment of Obesity, or BEAT Obesity (a collaborative study between Johns Hopkins Hospital and Mt. Sinai Hospital in New York). Before the procedure, 20 morbidly obese patients who weighed less than 400 pounds and had BMIs over 40 received weight management counseling.
Weiss said almost everyone lost a significant amount of weight over the first 60-90 days after the procedure. They averaged a 7 percent total weight loss. By 180 days, the effects of the embolization seemed to have dropped off. There were no major adverse events. Eight of the 20 patients had minor superficial ulcers on the lining of their stomachs. These ulcers healed after 3 months.
“We think this is a well-tolerated procedure,” he said. “It appears to be effective in the short and intermediate term.”
Weiss hopes that with continued research, the procedure will be approved by the Food and Drug Administration in the near future.
Another potential treatment for obesity might be cryotherapy, pioneered by Dr. David Prologo at Emory University. Weiss said the approach uses extreme cold to freeze the vagus nerve, which send signals from the stomach to the brain. In cryotherapy, a probe is inserted near a nerve. Once the probe is near the nerve, it creates an ice ball, which acts to damage the nerve. Interrupting the nerve’s signals might reduce the sensation of hunger.
Weiss predicted doctors will one day treat obesity “the same way we treat patients with cancer or other complex diseases, which is a multifactorial approach. Maybe it’s surgery followed by bariatric arterial embolization, maybe it’s cryotherapy followed by diet and exercise followed by something we haven’t even thought of yet.”