The researchers warned that a new weight loss procedure was losing muscle and fat to patients.
Embolization of the left gastric artery is considered an alternative to invasive gastric bypass surgery, but has an unexpected side effect.
Obesity is a major health problem worldwide, linked to serious diseases such as heart disease, cancer and diabetes. At age four, 10% of children are obese, which represents a 20% increase at the age of 10 years. In adulthood, this proportion increases to 25%.
First-line treatments such as diet and exercise often do not work, which causes many patients to opt for gastric bypass surgery, an effective procedure known to help morbidly obese people lose weight.
The researchers said the loss of muscle mass is worrisome and emphasizes the importance of proper nutritional counseling after the procedure
Gastric bypass involves tying a band around the stomach to make it smaller, but involves significant costs and potential complications.
Currently under study in the context of clinical trials, embolization only requires the reduction of blood flow to the upper part of the stomach, called bottom of the eye.
People are hungry when the ganglion releases the hormone ghrelin. Studies have shown that reducing blood flow in the stomach will slow the release of ghrelin, thus decreasing appetite.
During the procedure, microscopic beads are injected under imaging control into the artery feeding the blood into the stomach.
It has proven effective in reducing weight, but an unwanted side effect has been a significant muscle loss.
The researchers said the loss of muscle mass is worrisome and stresses the importance of proper nutritional counseling after the procedure.
Dr. Edwin Takahashi, senior author and researcher in Vascular and Interventional Radiology at the Mayo Clinic in Rochester, Minnesota, said: "Much research has been devoted to the effectiveness of the embolization of the 39, gastric artery for weight loss.
"However, there is no data on what contributes to weight loss, whether patients lose fat, as desired, or muscle mass, or a combination of both."
To learn more, Dr. Takahashi and his team studied the CT scan of 16 overweight or obese patients who had embolized the left gastric artery to treat gastrointestinal bleeding.
CT scanners, when used with special software, measure body composition based on different tissue densities such as fat and muscle.
The analyzes were done before and about a month and a half after the procedure.
The results were compared to those of a control group of 16 ambulatory patients who did not have embolization of the left gastric artery, but underwent a CT scan at two different times for nonspecific abdominal pain.
All 16 individuals lost a lot of weight after embolization, losing an average of 6.4% of their weight in a month and a half.
The body mass index, a measure of body weight in relation to the size of a person, decreased by 6.3%.
Although weight loss was not surprising to researchers, changes in body composition have been.
The skeletal muscle index, a measure of the amount of muscle that connects to the skeleton and helps move limbs, decreased by 6.8%.
Skeletal muscle is important for health and its loss can impair physical function and metabolism and increase the risk of injury.
Dr. Takahashi said: "The significant decrease in the amount of skeletal muscle highlights the fact that patients who undergo this procedure risk losing muscle mass and must be managed accordingly after the procedure.
"We need to make sure that they receive adequate nutrition to minimize the amount of muscle tissue that they lose."
Patients have also lost a significant amount of body fat.
Their overall body fat index decreased by an average of 3.7%.
However, most of the fat loss was subcutaneous or directly under the skin.
Visceral fat, the most dangerous fat surrounding organs and associated with serious health problems such as heart disease and diabetes, has not decreased significantly during follow-up.
The researchers plan to expand their studies in the future to people who undergo embolization as a treatment for obesity.
The study was presented at the annual meeting of the North American Radiology Society (RSNA) in Chicago.