FORT LAUDERDALE, Fla. -- A kind of pacemaker for the tummy, an implanted, electrical device that fools the body into feeling full, seems to be an effective alternative to radical digestive surgery for helping obese people shed a lot of weight. If it proves out in larger studies, the experimental device could offer a new way to help obese people slim down when they cannot lose weight on diets or with appetite-suppressing drugs. Researchers presented preliminary data yesterday on the device, which has been tested on 450 people.
Surgical techniques that shrink the stomach and reroute the digestive tract are the only highly reliable way to make obese people lose weight. But this is major surgery that carries significant risk, including a 1 percent chance of death, and researchers are searching for ways to do the job more safely.
The device is called an implantable gastric stimulator and is similar to a cardiac pacemaker. But instead of stimulating the heart, this one is attached to the wall of the stomach and is intended to reduce feelings of hunger.
Researchers implanted the devices in 30 women and men whose average weight was 242 pounds. Their average body mass index, or BMI, was 42. The healthy cutoff for the height-to-weight ratio is 25; 30 is considered obese.
After a year with the implant, two-thirds of the volunteers had lost weight. The average was an 18 percent drop in excess weight.
"The results are promising, although we still have a long way to go," Dr. Scott Shikora said. "I believe in my heart this is a very exciting breakthrough in our field."
Shikora, head of bariatric surgery at Tufts-New England Medical Center in Boston, presented the study in Fort Lauderdale at a meeting of the American Association for the Study of Obesity. The study was financed by the device's developer, Transneuronix Inc. of Mount Arlington, N.J.
The system uses an electrical pulse generator, a little larger than a silver dollar, that is placed under the skin in the abdomen and connected to the stomach with two wires. Implanting it takes less than an hour in an outpatient laproscopic procedure.
"These early findings are exciting," said Dr. Samuel Klein of Washington University, president of the obesity association. "This is a potential new approach for the management of obesity that is separate from drugs or surgery."
The device is on the market in Europe but is several years from approval by the US Food and Drug Administration. Steven Adler, executive vice president at Transneuronix, said the company hopes to begin in a few months a study on 120 patients that will take two years to complete.
After installing the pacemaker, doctors crank up the power until patients feel unpleasant symptoms, such as nausea or cramps, then turn it down a bit until all sensation disappears.
"They don't feel a buzzing or a pain," Shikora said. "They just don't have an appetite, or they get full very quickly. Some say: `I don't know what it is. I just eat different now.' "
Weight reduction varied widely. While about one-third in the study lost nothing, some had a lot of success. One patient lost 104 percent of her excess weight, meaning she now weighs slightly less than her ideal size.
Some have wondered whether the benefits are due to a placebo effect because patients wanted to lose weight and knew they were being treated.
But one patient's experience suggests otherwise. After getting the device, she failed for a year and a half to lose weight. Then doctors learned one of the wires had come loose. After they reattached it, she dropped almost 100 pounds.
"If there was placebo effect, she should have lost weight at the get-go, not after 18 months," Shikora said.
The device is hooked near the stomach's major nerves. Surgeons are unsure exactly why it seems to suppress appetite. Possibilities include an impact on the nerves, changes in digestive hormones, or direct stimulation of stomach muscles.