Bariatric Embolization for the Treatment of Obesity: A Review

Bariatric embolization has been discussed as a possible treatment for obesity since first early pre-clinical studies were done by Arepally et al in 2007. While much work in this field has been done, there remain many challenges prior to full clinical implementation. The current state of BAE was recently reviewed in JVIR by researchers from Johns Hopkins. Weiss et al. provide a thorough review of the physiologic and anatomic basis along with a review of the preclinical and clinical data. If successful, BAE will represent a minimally invasive solution to obesity offered by interventional radiologists.

Comment:

This manuscript does an excellent job reviewing the topic of BAE. The physiologic and anatomic basis for the procedure along with the current preclinical and clinical data are reviewed well. Clearly there are many challenges to mainstream implementation of this procedure. Many questions remain unanswered. What is the ideal embolic agent? What is the long-term outcome and will this procedure result in sustained weight loss? What is the best method of targeting the appropriate vascular bed? As more robust clinical trials provide answers to these questions, we will be closer to understanding the role this procedure may have in the treatment of this prevalent disease process.


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Angiogram of the left gastric artery. Fundal (solid arrows) and esophageal (dashed arrow) branches are identified. This LGA shows a large anastomosis (arrowheads) with the right gastric artery along the lesser curvature.

Hormonal changes during the fasting versus fed states. Several hormones are released from the GI tract. The “hunger hormone” ghrelin is secreted from X/A cells in the gastric fundus, whereas PYY and GLP-1 are secreted from L cells, primarily from the ileum and colon. Leptin is primarily produced in adipocytes. During fasting, decreased food intake suppresses the release of PYY, GLP-1, and CCK from the gut while stimulating the secretion of ghrelin by the stomach. Fasting also decreases serum leptin levels. These changes are detected by the brain, leading to hunger. Dieting results in a gut hormone profile that mimics the fasted state. During and after regular feeding, there is a reduction in the production of ghrelin by the stomach. In contrast, production of PYY, GLP-1, and CCK from the gut is increased, and serum leptin levels also increase. These changes, which are detected by the brain, result in decreased appetite and a feeling of satiety.


Citation: Weiss, C. R. et al. Bariatric Embolization of the Gastric Arteries for the Treatment of Obesity. Journal of Vascular and Interventional Radiology (2015). doi:10.1016/j.jvir.2015.01.017


Post author: Luke Wilkins, MD

Biodegradable stents show high technical and clinical success

The midterm efficacy of a biodegradable poly-L-lactic acid (PLLA) stent in the treatment of SFA occlusive disease was assessed in 35 de novo lesions between June 2009 and April 2011. This was a retrospective review and included patients ranging from Rutherford 2 to 5 with TASC II A and B lesions ranging from 2.5-13 cm (mean 6.8 cm). Over half (57.1%) of the lesions were occlusions. Follow-up included clinical examination and color-flow duplex imaging. Researchers reported a technical success rate of 100% with no intraoperative or 30 day complications. Primary and secondary patency rates were 77.1% and 97.1% at 24 and 36 months, respectively. At 30 mo, US confirmed complete resorption of the stent structures. Clinical improvement was defined as upward shift of at least 2 Rutherford categories and was seen in all patients.

Comment:

The data presented in the above manuscript are very promising and reflect acceptable patency rates in a well-represented study population. However, as illustrated in the manuscript, many questions remain unanswered in this potential “new frontier.” Will long-term studies show inflammatory changes and/or foreign body reaction resulting in increased rates of late restenosis secondary to hyperplasia? Will drug-eluting technology increase long-term patency rates and what will the optimal agent be? Will a multicenter randomized trial comparing BMS, DES, and biodegradable stents be supported? Clearly these questions, and many others, will need to be answered before this technology may be fully adopted. Regardless, the manuscript is noteworthy and contributes to the existing body of literature in this evolving field.

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Macroscopic view of the Igaki–Tamai stent, a premounted, balloon-expandable PLLA stent that is also self-expandable with straight bridges and gold markers at both ends (arrows). The PLLA monofilament (molecular mass, 183 kDa) coil stent is designed in a zigzag helical structure. The PLLA decomposes in the presence of oxygen following implantation, over a period of 12–18 months. (Reproduced with permission from Kyoto Medical Planning).

Angiographic images of a short, severe lesion of the distal SFA before (a) and after (b, c) deployment of the Igaki–Tamai stent. The arrows highlight the location and visibility of the proximal and distal gold markers.


Citation: Silingardi, R. et al. Midterm Results of Endovascular Treatment of Superficial Femoral Artery Disease with Biodegradable Stents: Single-Center Experience. Journal of Vascular and Interventional Radiology (2015). doi:10.1016/j.jvir.2014.10.050


Post author: Luke Wilkins, MD

Preoperative embolization in surgical treatment of spinal mets shows no improvement in intraoperative blood loss

Researchers from Denmark performed a prospective study evaluating the clinical efficacy of preoperative embolization of spinal mets undergoing spinal decompression. Researchers evaluated intraoperative blood loss, rate of transfusion with pRBCs, and operative time. No significant difference in intraoperative blood loss or pRBC transfusion was detected when comparing embolization versus non-embolization groups. There was, however, a significant reduction in operative time. Interestingly, inclusion criteria did not include hypervascularity of the tumor and sub-group analysis demonstrated a statistically significant reduction in blood loss when comparing hypervascular tumors. While the difference in blood loss was less than 500 mL and not considered to be clinically significant as no significant change in transfusion rate was detected.

Comment:

While the manuscript makes a convincing argument that preoperative embolization in patients undergoing spinal decompression does not produce clinically significant results, many questions remain unanswered. Given the subgroup analysis, one could argue that pre-operative embolization of hypervascular tumors may still improve clinical outcomes. However, criteria for determining vascularity was objective and not dependent on tumor type. If your current practice involves pre-operative embolization of hypervascular spinal mets, further research may be warranted before you decide to stop offering that service.


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Grading scale of hypervascularity. (a) Tumor blush equaling no hypervascularity (grade 0). Supply to the anterior spinal artery is present (arrow). (b) Tumor blush equaling moderate hypervascularity of a metastasis (grade 2). (c) Preoperative angiogram showing tumor blush equaling pronounced hypervascularity of a metastasis (grade 3).


Citation: Clausen, C. et al. Preoperative Embolization in Surgical Treatment of Spinal Metastases: Single-Blind, Randomized Controlled Clinical Trial of Efficacy in Decreasing Intraoperative Blood Loss. Journal of Vascular and Interventional Radiology (2015). doi:10.1016/j.jvir.2014.11.014


Post Author: Luke Wilkins, MD