The study design and initial 30-day safety data of the BEAT Obesity (Bariatric embolization of arteries for the treatment of obesity) study were presented at the SIR annual scientific meeting in Atlanta.
Bariatric embolization is a minimally invasive, image-guided therapy targeting the functionality of the stomach. It involves the targeted delivery of embolics to defunctionalise specific portions of the stomach that produce the hunger hormone, ghrelin.
BEAT Obesity is a physician-sponsored investigational device exemption single-arm prospective clinical trial for five to 15 morbidly obese patients. The embolic agent used (off-label) is 300–500μm Embosphere microspheres (Merit Medical) and the primary endpoints are weight loss and 30-day adverse events.
Clifford R Weiss, Radiology/Vascular and Interventional Radiology, The Johns Hopkins University School of Medicine, Baltimore, USA, presenting the update on the study said that of over 50 patients screened, 15 had been consented. Of these, six were excluded due to active Helicobacter pylori infections, diabetes, anatomic variants on CT , ulcers and polyps on screening endoscopy. “Three patients have been embolized to date and a further two are scheduled for the procedure,” he said.
The procedure consists of a series of steps beginning with coeliac digital subtraction angiography via the femoral approach. This is followed by cone-beam CT of the coeliac using the Zeego (Siemens). Then, selective digital subtraction angiography of the gastroduodenal artery and splenic artery are performed, followed by selective angiography of the left gastric artery. The researchers then embolize the left gastric artery using Embospheres to stasis. This is followed by digital subtraction angiography of the left gastric and repeated coeliac angiography and cone-beam CT, if contrast and dose area product (DAP) allow.
The BEAT Obesity results showed that the average procedure time was 143±39.2 minutes; fluoroscopy time was 22.8±8.6 minutes; radiation dose was 4546.7±267.3mGy; contrast dose was 182.3±55.9cc and volume of beads delivered was 3.3±0.6cc,” Weiss said.
The 30-day results showed that there were no major adverse events. The median weight loss was 10.3±6.4lbs. There was one hospital admission for nausea and vomiting.
Weiss added: “Early evidence suggests that bariatric embolization is a safe and effective treatment for morbid obesity. Aggressive diet intervention is essential and should begin well before bariatric embolization. It is important to assess the anatomy of the patient before the procedure, and as a specialty we must learn how to manage these patients in a multidisciplinary fashion.”
Bariatric embolization using polyvinyl alcohol particles
Research from Korea, presented at the European Congress of Radiology (ECR, 4–8 March, Vienna, Austria), shows that bariatric embolization using non-spherical polyvinyl alcohol particles works to suppress ghrelin in swine models.
J Kim, Seoul, Korea, told delegates that this type of embolization can significantly suppress ghrelin level. “However, we identified ulcerations in the stomach in 50% of experimental animals. Three (50%) animals also demonstrated recanalisation of the embolized vessels in follow-up angiography,” he said.
The investigators performed embolization using an infusion of 150–250µm polyvinyl alcohol selectively into the gastric arteries that supply the fundus. Six healthy swine underwent bariatric embolization, while five control animals underwent a sham procedure with saline. Plasma ghrelin levels were obtained in animals at baseline and at every two weeks. Endoscopy was performed three weeks after bariatric embolization to look into the occurrence of ulceration in stomach. Repeated angiography of the coeliac trunk was done to determine the durability of the occluded arteries. And necropsy was performed eight weeks later.
Kim reported that the pattern of change in ghrelin levels over time was different between control and experimental animals. Average postprocedure ghrelin values maximally decreased in experimental animals at week five relative to baseline.