SIR 2017: Bariatric arterial embolization - an interventional procedure to reduce severe obesity
Bariatric arterial embolization (BAE), or transarterial embolization of the left gastric artery, is a new, minimally invasive image-guided procedure to treat severe obesity. Preliminary outcomes of a pilot prospective clinical trial under way at Johns Hopkins University School of Medicine show that this may become a safe and effective interventional procedure.
BAE aims to directly modulate the neurohormonal axes of hunger by altering the endocrine function of the gastric fundus, particularly with respect to reducing production of ghrelin. One of five sections of the stomach, the fundus serves as the epicenter for the neuroregulatory pathways involved with satiety and appetite stimulation. The fundus produces the largest amount of ghrelin, the most potent hunger-stimulating hormone. BAE uses targeted transvascular delivery of embolic microspheres into the gastric arteries to alter the ghrelin production. The procedure also indirectly affects acid production, gastric motility, and possibly absorption.
The Bariatric Embolization of Arteries for the Treatment of Obesity (BEAT Obesity) study is evaluating 20 severely obese patients who underwent a BAE to evaluate its feasibility, safety, and outcomes. The primary end point was 30-day adverse events, and secondary endpoints were short-term weight loss, serum obesity-related hormone levels, hunger and satiety, and quality of life. The patient cohort includes four men and 16 women, ranging from 27-68 years. They weighed between 218-391 pounds (mean 283 pounds) with a body mass index (BMI) of 39.7-55.5 (mean 45.1) at baseline.
Principal investigator Clifford R. Weiss, MD, associate professor of radiology and radiological science and medical director of the Johns Hopkins Center for Bioengineering, Innovation and Design, explained the procedure that he and his colleagues used at a scientific session of the annual meeting of the Society of Interventional Radiology (SIR). Celiac digital subtraction angiography (DSA) was initially performed followed by cone beam CT to fully assess the patients’ visceral vascular anatomy and stomach perfusion. The cone-beam CT protocol was a modified liver parenchymal blood volume protocol. Angiography was performed using a coaxial microcatheter system. Embolization of one or more fundal arteries was performed with a high-flow microcatheter system with 300-500 μm Embosphere microspheres. Standard angiographic end points of stasis or substasis were applied.
The technical success rate was 100% and no patients experienced any major adverse effects. Eight patients developed small ulcers, which healed within 90 days. One patient experienced delayed gastric emptying at 30 days, and another developed transient pancreatitis demonstrated by mild abdominal pain, nausea and elevation of lipase levels.
One-month data were available for all 20 patients. Twelve-month data were available for four patients, 6-month data for 10 patients, and three-month data for 17 patients. Dr. Weiss reported that one month following the BAE, the mean weight reduction was 12.1 pounds, representing an average excess weight loss of 8.2%. The four patients who were at one-year follow-up had an average excess weight loss of 15.1%. Mean percent change of serum ghrelin from baseline was 8.7% at one month and 17.5% at three months.
Dr. Weiss said that the BEAT Obesity trial was designed specifically to reproduce a small-scale multidisciplinary bariatric surgery trial with clear end points and to build on existing preclinical data. He pointed out that a larger bead size of 300-500 μm was specifically chosen per FDA guidance because of concerns about gastric ischemia and ulceration. This was 10 times larger than the size of embolic beads used in preclinical studies. A greater reduction in ghrelin may be achieved if smaller beads are used, and future clinical studies will investigate this.
“Bariatric embolization represents a new treatment and a new patient population that we as interventional radiologists may be able to help in a modern and minimally invasive fashion. I believe this is what really excites my colleagues in interventional radiology,” Dr. Weiss told Applied Radiology.
“Small trials have started throughout North America and around the world. We are excited to see the burgeoning effort in this area and look forward to organizing a large, multi-center, phase 3 protocol once enough preliminary data has been collected,” he said.
REFERENCES
- Weiss CR, Akinwande O, Paudel K., et al. Clinical safety of bariatric embolization: Preliminary results of the BEAT Obesity trial. Radiology. Published online February 14, 2017. (doi: 10.1148/radiol.2016160914).
- Weiss CR, Gunn AJ, Kim CY et al. Bariatric Embolization of the Gastric Arteries for the Treatment of Obesity. J Vasc Interv Radiol. 2015 26;5: 613-624.
- Weiss CR, Kathait AS. Bariatric embolization: a new and effective option for the obese patient? Expert Rev Gastroenterol Hepatol. 11;4: 293-302.