Left gastric artery embolization shrinks both fat and muscle

Left gastric artery embolization is a new interventional procedure to treat obesity. A study has found that the procedure leads to the loss not only of fat but also of muscle.

The researchers presented details of their study and findings at the Annual Meeting of the RSNA in Chicago, Illinois. RSNA stands for the Radiological Society of North America.

According to the researchers, the loss of muscle mass is ‘concerning.’ They added that the muscle loss underscores the importance of proper nutritional counseling post-procedure.

Obesity, a major global health issue, is linked with serious conditions like diabetes, cancer, and heart disease. First line treatments are often ineffective. Diet and exercise are examples of first line treatments.

Consequently, many patients choose to have gastric bypass surgery. Surgery involves reducing the size of the patient’s stomach. The procedure has been effective in treating obesity. However, there are risks of potential complications. It also carries with it significant costs.

Left Gastric Artery Embolization
The surgeon injects microscopic beads into the bloodstream. They make their way to to the artery, where they block the smaller blood vessels. This minimally-invasive non-surgical technique is accomplished through a small catheter in the groin or wrist. (Image: adapted from facebook.com/gbmc.jo/photos)

Left gastric artery embolization under investigation

Left gastric artery embolization is a less invasive option to surgery. The procedure is currently under investigation in clinical trials.

With left gastric artery embolization, the surgeon injects microscopic beads into the artery that supplies the stomach with blood. The surgeon uses imaging guidance to place the beads in the right place.

Ghrelin production

The beads block the flow of blood to the stomach and reduce ghrelin production. Ghrelin has numerous functions, one of which is stimulating appetite. Hence, people refer to it as the ‘hunger hormone.’

Initial studies had shown that the procedure is effective in helping patients lose fat. However, there was no data regarding how it might alter patients’ composition of fat and muscle.

Edwin A. Takahashi, M.D. said:

“There has been lots of research focused on the efficacy of gastric artery embolization for weight loss. However, there has been no data on what is contributing to the weight loss, whether the patients are losing fat, as desired, or muscle mass, or some combination of the two.”

Dr. Takahashi is a vascular and interventional radiology fellow at the Mayo Clinic in Rochester, Minnesota, USA.

Studying CT scans

Dr. Takahashi and colleagues wanted to learn more, so they studied CT scans of 16 patients. They were all obese or overweight and had undergone left gastric artery embolization to treat gastrointestinal bleeding.

If we use CT scans in conjunction with special software, we can measure body composition based on different densities of muscle and fat.

The scans had been taken before and about 1½ months after the procedure. The researchers compared the results with those of sixteen patients who had not undergone left gastric artery embolization. However, they had CT scans at two different points in time for non-specific abdominal pain. This second group was the ‘control group.’

Control group vs. test group

In medical research, the ‘control group‘ is the group that does not receive the treatment that the researchers are studying. In an experiment or study, the researchers compare everything else with the data they gathered from the control group. The opposite of the control group is the ‘test group‘ or ‘experimental group.’

All sixteen patients in the test group experienced significant weight loss after the procedure. Over 1½ months, they lost an average of 6.4% of their body weight. Their BMI declined by 6.3%. BMI, which stands for Body Mass Index, is a measure of a person’s body weight relative to their height.

The researchers were not surprised that the patients had lost weight. The changes in body composition, on the other hand, did surprise them.

Skeletal muscle index decline

Their skeletal muscle index fell by an average of 6.8%. Skeletal muscle index is a measure of the amount of muscle that connects to the skeleton. These muscles help move our arms and legs.

Skeletal muscle is crucial for good health. Its loss can impair metabolism and physical function. It can also put an individual at higher risk of injury.

Dr. Takahashi said:

“The significant decrease in the amount of skeletal muscle highlights the fact that patients who undergo this procedure are at risk for losing muscle mass and need to be managed accordingly after procedure. We must make sure they receive adequate nutrition to minimize the amount of muscle tissue they lose.”

Subcutaneous fat vs. visceral fat

The sixteen patients also lost a considerable amount of body fat. Their overall body fat index declined by an average of 3.7%.

Much of the loss was of fat that lies directly under the skin. In other words, most of their fat loss consisted of ‘subcutaneous fat.’

The loss of visceral fat was not significant, the researchers noticed. Visceral fat is the fat that the body stores in the abdominal cavity. This type of fat exists around the intestines, liver, pancreas, and other organs in the abdominal cavity.

If you have a huge belly, ‘pot belly, ‘paunch,’ or a ‘beer gut,’ you have too much visceral fat. People who store too much visceral fat have a higher risk of developing type 2 diabetes, heart disease, and cancer.

People with a ‘pear-shaped’ body have lots of fat under the skin. Individuals with an ‘apple-shaped’ body, on the other hand, have lots of visceral fat. A pear shaped body is usually healthier than apple shaped one.

The researchers say they want to expand their studies in the future. This will include patients who underwent left gastric artery embolization specifically for the treatment of obesity.