Obesity is a national public health crisis currently affecting nearly 93.3 million Americans (approximately 40% of all adults over the age of 20) in the United States. -published in JAMA in 2018. Severe obesity is defined as having a body mass index (BMI) equivalent to or above 40 kg/m2. Obesity is a chronic, multifactorial disease associated with otherwise preventable physical diseases and mental health problems also known as co-morbidities. Genetics, existing medical conditions, life-style and behavioral factors, and social and economic factors all contribute to chronic obesity. In addition to serious health consequences this epidemic costs the healthcare system an estimated annual health care cost of a staggering $190.2 billion or nearly 21% of annual medical spending in the United States.
The alarming increase in prevalence of obesity over the past decade suggests the ineffectiveness of current treatment methods comprised of behavioral health therapy; restricted diet, intensive medical monitoring of progress, and implementing major lifestyle changes simply are not effective enough to overcome this life-threatening, widespread disease. Surgical intervention is the last recourse remaining for bariatric patients who have continually failed conventional treatment methods resulting in exacerbation of comorbidities leading to the inevitability of death. “Less than 1% of eligible patients choose to undergo such surgery due associated risks of mortality.”
Modern advances in radiologic technology provide the means necessary for an introduction to a minimally invasive, trans-arterial, percutaneous procedure more commonly known as Bariatric Arterial Embolization (BAE) as a supplemental method to facilitate weight loss. This procedure specifically targets gastric arteries utilizing fluoroscopic image guidance, angiograms and cone-beam CT (CBCT) imaging systems to ensure precise placement of an artificial embolus by a co-axial multi-catheter. Disruption and cessation of blood flow caused by localized ischemia that targets effects physiological release of hormones directly related to regulating appetite, metabolism, and reducing co-morbidities of chronic morbid obesity.
Many medical facilities are not equipped to treat obese patients, particularly radiologic imaging technology due to weight limits, and poor quality images due the primary source of scatter: fat. BAE has created a viable treatment option in a field that hasn’t been always been able to provide optimal care to this particular cluster of patients, insinuating obesity is a serious disease requiring new methods of treatment and not a personal choice. Regulation of this supplemental treatment could help eliminate the stigma and shame that prevents many morbidly obese patients from seeking medical intervention. “If weight stigma promoted healthier lifestyle behaviors and weight loss, then the documentation of increased weight stigmatization over the past several decades should be accompanied by a reduction in obesity rates, rather than the alarming increase.”
The purpose of this research paper is to emphasize the importance of radiologic technology in performing BAE and its effects contributing to expediting weight-loss in morbidly obese patients. The research and results have been obtained through extensive investigation of numerous credible studies and websites including the BEAT Obesity trial and Radiologic Society of North America website.
Bariatric embolization would not be possible without radiological imaging technology. The first step is to conduct a common fluoroscopic procedure known as a celiac digital subtraction angiogram (DSA) to clearly visualize the vascular anatomy through the dense abdominal tissue. Utilizing the image intensifier a pre-contrast photo is taken, then it successively takes images of the gastric arteries once contrast is applied by the radiologist. Each of those images are subtracted from the original no-contrast image. This produces a short scale, high-contrast image. By darkening the vessels, lightening the background, and removing detracting structures overall vascular visualization is enhanced. The next step is conducting an arterial phase cone-beam computed tomography exam (CBCT) to confirm the blood supply in the gastric fundus. Cone-Beam CT exposes the patient to less radiation while enhancing visualization of bleeding vessels with increased contrast and spatial resolution making it preferred over conventional CT for this procedure. Next, percutaneous access to the celiac artery is obtained through the femoral artery using the Seldinger’s Technique.
The femoral artery can be located through use of palpable anatomic landmarks and veins, which proves to be difficult in morbidly obese patients resulting in implication of sonography to ensure accurate insertion of the micro-catheter access needle. Then, with use of fluoroscopic guided angiogram a guide wire is advanced through the needle subsequently removing the needle and inserting a sheath over the guidewire to allow access of catheter into artery. A high flow co-axial multi-catheter is used to access the left gastric artery to place a radiopaque, calibrated embolization microsphere (TMGs – trimethylol acryilic acid microsphere) disrupting blood flow until it is taken to stasis. Cessation of flow is then followed up by injection of contrast to evaluate success of embolization. Finally, a second CBCT is obtained to ensure proper distribution of microspheres and optimal degree of embolization.
Results stating effectiveness of this procedure were obtained from the BEAT obesity trial. Morbidly obese patients with a BMI over 30 kg/m2 underwent BAE and were monitored and evaluated for safety and efficiency of the surgery at 3, 6, and 12 month intervals. Due to the rich collateral supply to the stomach, BAE is well tolerated with an impressive major complication of 0%. – pubrsna. Only 8 participants had a total of 11 adverse effects comprised of transient abdominal pain, nausea, vomiting, and gastric ulceration/ perforation. The primary mechanism of action is mediation of the appetite stimulating or “hunger” hormones Ghrelin and Leptin. Ghrelin is the most potent appetite stimulating hormone most responsible for affecting body weight and fat storage, where leptin controls satiety and appetite suppression. Both hormones are produced primarily in the gastric fundus and leptin regulates ghrelin. High levels of fat result in increased levels of leptin, resulting in a tolerance build-up or resistance to the appetite suppressing factors of this hormone.
BAE achieved maximal appetite suppression only one month after the procedure, increasing thereafter remaining 26% lower than baseline at 12 months. Metabolic changes even before initial weight loss include the following: reduction of hemoglobin A1C (HbA1C) and an increase Glucagon-like peptide 1 (GLP-1) and high density lipoprotein levels. Reduction of hemoglobin A1C reduces the prevalence of the protein in red blood cells that binds to glucose, reducing blood-glucose plasma levels that consequently contribute to development of type 2 diabetes. Glucagon-like peptide 1 also plays a primary role in diabetes management. It suppresses glucose release and delays stomach emptying and increases insulin sensitivity subsequent to eating. Feelings of fullness will last longer, which allows the cells of the body to use blood glucose more effectively, reducing blood sugar and possibly type 2 diabetes. Increase in lipoprotein levels increase amount of cholesterol removed from the blood reducing the risk of atherosclerosis and heart disease.
Overall, BAE was effective in 20 adults with severe obesity with a mean weight loss of 11% or 16.75lbs with peak weight loss occurring 6 months prior to the procedure. After 12 months only 3 patients returned to their baseline weight. “Weight loss of a mere 5-10% can decrease risks of hearts disease, diabetes, hemoglobin, triglycerides, blood pressure and need for diabetes or antihypertensive medications.”
In conclusion, bariatric embolization as a supplemental treatment of chronic obesity can produce substantial weight loss. Clinical changes after bariatric embolization reflected improved cardiovascular health and prevention of diabetes. Furthermore, participants reported improvements in quality of life after embolization such as increase in physical function and self-esteem and a decrease in public distress after 3 months. BAE will one day become a standard of care in a more personalized approach to treating obesity while reducing stigma of a disease increasingly understood to affect each patient differently.
