Reducing obesity

In studies, UC Irvine surgeons find bariatric surgery safer, gastric bypass most effective

Bariatric surgery is an increasingly popular way to treat morbid obesity. More than 170,000 Americans undergo the surgery each year, 10 times more than in the mid-1990s.

Two recent studies by UC Irvine Medical Center surgeons compared the outcome, quality of life and cost of the two most performed procedures and examined whether expanded Medicare coverage had enhanced their safety.

"Patients who qualify for bariatric surgery can choose between gastric bypass and gastric banding," says Dr. Ninh T. Nguyen, who led the studies. "The operations have become more streamlined and efficient, but we wanted to determine which is truly better by looking at the risks and benefits of each."

Gastric bypass achieves weight loss by rerouting the small intestine to a truncated stomach pouch, while gastric banding constricts the size of the stomach with an implanted ligature. The first study, published in the Annals of Surgery, involved 111 people who had laparoscopic bypass and 86 who had laparoscopic banding.

Nguyen, UC Irvine Medical Center's chief of gastrointestinal surgery, Drs. Johnathan Slone and David B. Hoyt, and researchers Xuan-Mai T. Nguyen and Jaimee S. Hartman found both techniques to be safe and effective for morbid obesity.

Gastric bypass resulted in better weight loss, though patients had more complications. Gastric banding recipients experienced wider variation in weight loss, with 16.7 percent—more men than women—losing less than 20 percent of excess weight, which was considered a failure. There were no failures among bypass patients.

In February 2006, Medicare expanded coverage of bariatric treatments but limited it to those performed at sites certified by the American College of Surgeons or the American Society for Metabolic & Bariatric Surgery that do at least 125 operations annually.

For the second study, published in the Archives of Surgery, Nguyen, Slone, Hoyt and fellow UC Irvine doctors Esteban Varela and Brian R. Smith analyzed the outcomes of more than 6,200 patients who underwent bariatric procedures in the 18 months before and after the modification of Medicare coverage.

While the frequency of bariatric surgery remained fairly steady in that period, the number of U.S. facilities offering it decreased from 60 to 45, reflecting a shift to high-volume, certified centers.

Researchers found that treatments at these centers resulted in shorter hospital stays and fewer complications and deaths. A pre-2006 study had shown 30-day mortality rates of up to 2 percent for Medicare patients—"too high," according to Nguyen. The rate after the coverage expansion was 0.2 percent.

Recently named chairman of the advisory committee for the American College of Surgeons' Bariatric Surgery Center Network, Nguyen will next lead a trial exploring whether two connected balloons inserted into the stomach through the esophagus can induce weight loss similar to that achieved through the more invasive bypass and banding procedures.

The idea of using a gastric balloon to help patients feel less hungry was developed in the 1980s, he says, but didn't pan out. The balloon sometimes ruptured and, if it slipped into the small intestine, caused an obstruction.

"The concept was good, but the technology wasn't ready yet," Nguyen says. It's hoped that the double balloon will be less problematic. UC Irvine, which performs up to 200 bariatric operations a year, is one of several certified centers around the country participating in the trial, which may begin this fall.

Nguyen is determined to find new weapons in the war against what some call an "obesity epidemic" in America.

"Obese individuals are at far greater risk of dying from coronary artery disease, type 2 diabetes, hypertension, gallbladder disease and certain cancers," he says. "It's critical to treat this condition."

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