a smaller particle embolic in swine, and reported efficacy in suppressing weight gain, plasma ghrelin levels and fundal ghrelin production by gastric X/A-like endocrine cells. However, the smaller- particle embolic also resulted in gastric ulceration in 40–50% of BE-treated animals, raising concerns about the potential for similar adverse events in humans. In addition, the prophylactic use of gastroprotectants (proton pump inhibitor and sucralfate) failed to prevent gastric ulceration, regardless of the number of fundal vessels embolized.26


Using two groups of larger particle embolics (100–300 m and 300–500 m diameter), Fu et al. demonstrated that BE using off-the-shelf 100–300 m microspheres was able to reduce body weight and gastric ghrelin-producing cell density to a greater degree than the larger, 300–500 m microspheres with a similar safety profile.27


The ideal embolic agent for bariatric embolization Based on subsequent preclinical investigations, the ideal embolic particles for BE should be sized to target submucosal layer vessels (75–120 m) in the gastric fundus and be image-visible to improve on-target delivery.28


These


findings have led to the development of X-ray-visible embolic microspheres (XEMs), which are approximately 50 m in size and specifically designed to optimize the safety and efficacy of BE.29,30 Extensive animal studies using XEMs demonstrated statistically significant weight loss in treated animals compared to controls. Plasma ghrelin levels were lower in BE-treated swine than control animals, while plasma levels of GLP-1


1973


Embolization for pelvic trauma is introduced.


The Society of Interventional Radiology is founded as the Society of Cardiovascular Radiology (SCR).


and PYY were consistently higher than in controls.29


A follow-up prospective,


single-arm clinical trial examining BE using a novel, image-visible, 100–200 m embolic microsphere specifically designed for BE is currently underway (clinicaltrials.gov: NCT04197336).


Human clinical trials of BE With over 100 patients treated worldwide, more than half a dozen prospective human clinical trials have demonstrated significant weight loss after BE, without any major adverse sequelae. In a meta-analysis of six prospective, single-arm clinical trials of BE consisting of 47 patients with obesity (mean age: 38–48 years, baseline weight: 79–160 kg, baseline body mass index [BMI]: 28.9-45 kg/m2), Hafezi-Nejad et al. reported a pooled mean weight loss of 8.11% ± 1.46% from baseline at 12 months (range: 4.77–17.19%). Furthermore, the first randomized, sham-controlled clinical trial of bariatric embolization, using 300–500 m embolic microspheres on 44 patients (treatment group N=22; control group N=22), was conducted in Eastern Europe. Of the 31 patients included in the per-protocol group, the participants exhibited a percent mean weight loss of 6.5% over the sham group (per-protocol 8.3% vs control 1.8% at 6 months). In the intent-to-treat (ITT) group, embolized participants demonstrated a percent mean weight loss of 3.6% over sham (intent-to-treat 6.4% vs control 2.8% at 6 months).31 Comparing these findings to behavioral obesity therapies, a meta-analysis of 22 studies on lifestyle modifications alone demonstrated a mean 4% weight loss from the participants’ baseline weight at 12 months.


1974 1975


Selective arterial thrombolysis for arterial occlusions, now used to treat blood clots, stroke, DVT, etc., is created.


Transhepatic embolization for variceal bleeding is introduced.


Further research Given the current limitations in obesity therapeutics, the Society of Interventional Radiology Foundation commissioned a Research Consensus Panel (RCP) to establish a research agenda on obesity therapeutics in IR. An 11-member RCP was assembled from a list of leading scientists and clinicians with expertise in metabolic physiology, nutrition science, obesity medicine, gastroenterology, bariatric surgery, IR, and US Food and Drug Administration (FDA) medical device pre-market regulation. The meeting provided a platform for a dialogue about the current state of obesity medicine and therapeutics, to review current evidence for experimental obesity interventions and establish a research agenda for the evaluation of emerging weight loss procedures in IR. The final list of prioritized research topics for IR obesity therapeutics, as voted by the RCP panelists and participants, included the following:


1. Where should IR obesity therapies fit into the obesity treatment schema?


2. What patient characteristics are best suited for IR obesity therapies?


3. What types of research data are necessary for treatment reimbursement?


The expert panelists reached a consensus that a staged approach for treating obesity, initially with behavioral and pharmacologic therapies, followed by minimally invasive IR or endoscopic interventions, and finally bariatric surgery for severe cases of obesity, ideally should be implemented. After reviewing data on IR bariatric interventions, the panelists identified several patient populations that could benefit from these novel


1976


(1960–74) Tools for interventions such as heparinized guidewires, contrast injector, disposable catheter needles and see-through film changer are created.


8 IRQ | SPRING 2021 SUPPLEMENT


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