A study carried out by the Stanford University School of Medicine using new measures of heart disease risk shows that gastric bypass surgery reduces the risk of heart disease even more than previously believed.
The researchers say the finding underscores the value of the surgery for extremely overweight people, whose obesity puts them in danger of heart attack, stroke and other cardiovascular illness.

The researchers measured biochemical cardiovascular risk factors in 371 patients before surgery and again 12 months after gastric bypass surgery, adding three new tests to the standard panel of cholesterol and triglyceride assays.
They saw improvements in all cardiac risk factors, with the most significant improvements for triglycerides and one of the new tests: C-reactive protein.

" Treatment with statins lowers C-reactive protein by about 16 percent. But we found that gastric bypass lowered it by 50 percent. That's a pretty significant improvement over what's been considered state-of-the-art therapy," said senior author John Morton, at the Stanford School of Medicine and director of Bariatric Surgery at Stanford Hospital.

Gastric bypass surgery, the most common form of weight-loss surgery, reduces the stomach's size to limit the amount of food intake and bypasses more than 35 inches of the approximately 20-foot-long small intestine, which cuts down on nutrient absorption.

The number of gastric bypass surgeries has shot up in recent years, increasing from 29,000 procedures in 1999 to about 141,000 in 2004.
The procedure poses about a 2 percent risk of mortality and requires lifelong changes in eating habits - but it's a life-saving operation for most morbidly obese individuals, Morton said.

" This operation is reserved for morbidly obese people, not the pleasantly plump," Morton said. "Being morbidly obese carries a pretty significant risk of premature death, in large part because of heart disease. The risk of premature death for the morbidly obese is about three times the risk of the general population."

More than 15 million people in the United States are morbidly obese, as measured by body mass index.
A BMI over 40 qualifies as morbidly obese, according to National Institutes of Health guidelines for bariatric surgery. So, for example, a person whose height is 5 feet 8 inches and weight is 265 pounds would have a BMI of 40 and would be considered morbidly obese.

Morton, Williams and Stanford colleagues knew from earlier studies by others that gastric bypass lowered many risk factors for heart disease but no large-scale studies had investigated the effects of the surgery on all three newer heart-disease markers - C-reactive protein, lipoprotein A and homocysteine, Williams said.

"All of the values improved to where they were no longer in the abnormal range. In other words, they normalized," Morton said.

The most significant decrease in risk was seen in C-reactive protein levels, which dropped from 10 mg/L to 3 mg/L. According to the Centers for Disease Control, C-reactive protein levels greater than 3 mg/L indicate high risk for cardiovascular disease.

Interestingly, the improvements went beyond what would have been expected due to weight loss alone. "We're not sure why, but the process of bypassing the stomach might induce some changes in both lipid and inflammatory metabolism," Morton said.

The lowering of cardiac risk factors was especially compelling given the patients' dire condition before their surgery, Williams said. "The study showed that these patients were at great risk of heart disease before their surgery. Their risk factors were even higher than we had expected," he said.

Source: Stanford University Medical Center, 2005


XagenaMedicine2005