By Randy Yeh, MD
The potential benefits of weight loss surgery are no secret. Nor are the implications and side effects of the procedures themselves, which involve the reduction of the stomach to a pouch the size of an egg, or inserting a constrictive band to achieve the same end.
Now, Harvard researchers may be on to a promising new and less invasive way to treat obesity - by simply blocking a particular blood vessel leading into the stomach.
Interestingly enough, the procedure itself is nothing new. Called transarterial embolization, it is a common treatment in which a doctor goes in through a blood vessel and injects tiny beads or coils to block this artery, usually to slow or stop problematic bleeding in the gastrointestinal tract.
But the treatment, it turns out, has a happy side effect. In a new study presented at this year's annual meeting of the Radiologic Society of North America (RSNA), those Harvard researchers looked back at medical records of 15 patients undergoing the procedure on a vessel supplying the stomach known as the left gastric artery. They noticed that, three months afterwards, these patients had lost about 8 percent of their body weight. And it was just this artery that seemed to matter; when looking at 18 patients in which a different artery was blocked off, they saw only a 1 percent decrease in weight.
Lead study investigator Dr. Rahmi Oklu said the reason that this might be the magic artery for weight loss is that this is the blood vessel that supplies the part of the stomach where the appetite-stimulating hormone ghrelin is produced. Knocking it out, he said, may decrease levels of this hormone - and thus lead to appetite suppression and weight loss.
"This is just an observation and a byproduct of an unrelated procedure and needs further investigation," said Oklu, assistant professor of radiology at Harvard Medical School. "But this could represent a new avenue of research for a minimally invasive approach to control weight loss."
Animal studies have shown lowered ghrelin levels and weight loss, but such studies have not been conducted in humans thus far.
If the finding holds up, it could be interesting indeed. Bariatric surgeries, such as Roux-en-Y gastric bypass and gastric banding, have become increasingly popular. According to the American Society for Metabolic and Bariatric Surgery, the number of people getting weight-loss surgeries skyrocketed from 13,000 in 1998 to over 200,000 in 2008, the most recent figure available. But while these procedures have been shown to be effective, they are not without risks and complications - infections, leaks at the surgical site, and, rarely, the need for re-operation.
A minimally invasive approach may be a safer alternative, Oklu suggested. "The fact that you can potentially control weight loss by a minimally invasive approach is massive, especially since obesity is a major public health problem in America," he said.
As far as its use in weight loss, of course, the procedure is not ready for prime time… at least not yet. Dr. Mitchell Roslin, chief of bariatric and metabolic surgery at Lenox Hill Hospital, who was not involved in the study, said that while there is some evidence in animals and even humans, the effects on weight loss may not be longstanding.
"My guess is that any response would be fleeting and gone in a year or two," Roslin said, adding that with any weight loss procedure, doctors have to look at how long the results last to justify it.
While these observations are preliminary, the potential for a novel, minimally invasive procedure to treat weight loss and obesity is both exciting and promising. Further research on more people showing sustained, long-term weight loss will be critical to decide whether left gastric artery embolization is a feasible option in the future.
The jury is still out, but it is important to remember that for most people, the old-fashioned advice for weight management still applies. This means crucial lifestyle modifications, such as a eating well-balanced diet and regular exercise - even if you do get a weight-loss procedure.