Now, a new study presented here at the annual meeting of the American Society for Metabolic & Bariatric Surgery suggests that benefit is maintained long-term. It followed some patients as long as seven years.
"The obese patient has substantially more cardiac risk factors, and that risk is improved after bariatric surgery across the board, regardless of individual cardiac risk factors," says researcher John Morton, MD, MPH, director of bariatric surgery at Stanford Hospitals & Clinics at Stanford University.
"This study shows that bariatric surgery's impact on cardiac risk factors is not only effective treatment but enduring," Morton says.
Bariatric Surgery & Heart Attack Risk: Study Details
All patients had gastric bypass, in which a stomach pouch is created out of a small portion of the stomach and attached to the small intestine. A large part of the stomach and some of the small intestine are bypassed.
In the study, 182 patients were followed for at least three years. By year seven, 57 patients remained for follow-up evaluation. Others dropped out.
''This is the largest long-term follow-up of cardiac risk factors after gastric bypass surgery," Morton tells WebMD.
The average age was 44 years. Before surgery, the patients' average BMI was 47 (a BMI of 30 or higher is considered obese). At the start, 33% had diabetes, half had high blood pressure, and nearly one-fourth were on statin therapy to reduce cholesterol.
By seven years, the average BMI was reduced to 34. Patients maintained a loss of about 56% of their excess weight. Weight declined from 286 to 205 pounds, on average.
Improvements in heart risk factors included:
- Total cholesterol declined from 184 before surgery to 174 after. (Below 200 is recommended.)
- HDL or "good" cholesterol rose 40%.
- LDL or "bad" cholesterol improved.
- Triglycerides (blood fats) declined by about 55%.
High-sensitivity C-reaction protein, a marker of inflammation -- which boosts risk for heart attacks -- declined by 80%, Morton says.
"We didn't see any cardiac events in these patients," Morton says.
Statin drugs, taken by about one in four before, were stopped after surgery. About the same number eventually had to go back on them. Morton says that reflects genetic factors making people vulnerable to high cholesterol.
Morton reports serving as a consultant for Ethicon Endo-Surgery Inc., which makes the Realize gastric band for weight loss surgery. He is on the scientific advisory board for Vibrant, which makes an implant system for weight loss.
Bariatric Surgery & Heart Attack Risk: Perspective
The long-term follow-up study ''reinforces what we already know," says Stephen Wohlgemuth, MD, a bariatric surgeon and medical director of the Sentara Metabolic and Weight Loss Surgery Center, Sentara Medical Group, in Norfolk, Va. Wohlgemuth is also an assistant professor of clinical surgery at Eastern Virginia Medical School in Norfolk.
He reviewed the findings for WebMD.
"Bariatric surgery, particularly gastric bypass, has a very protective effect on cardiac risk factors," he tells WebMD.
However, he notes that as the years went on, the number of patients declined as some were lost to follow-up. Although that is typical in any medical study, it results in incomplete information, he says.
"We base a lot of our information on a small number of patients," he says, due to those who drop out or are otherwise lost to follow-up.
However, even with those shortcomings, he says, gastric bypass, more so than other weight loss surgeries, appears to be linked with better improvements in heart attack risk and other indicators of wellness or disease.
These findings were presented at a medical conference. They should be considered preliminary, as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.