Liquid Embolization with Onyx in a Technically Challenging Case of Acute Upper GI Bleeding

Efficacy and Safety of Ethylene-Vinyl Alcohol (EVOH) Copolymer-Based Non-Adhesive Liquid Embolic Agents (NALEAs) in Transcatheter Arterial Embolization (TAE) of Acute Non-Neurovascular Bleeding: A Multicenter Retrospective Cohort Study

Background and Objectives: Transcatheter arterial embolization (TAE) is part of the daily practice of most interventional radiologists worldwide. The ideal liquid embolic agent is far from being identified. Non-adhesive liquid embolic agents (NALEA) harden from the outside to the inside, resulting in deep penetration, known as "magma-like" progression, which permits a more distal embolization with good control of the embolic material. This multicenter retrospective cohort study aims to assess the efficacy, feasibility and safety of transcatheter arterial embolization (TAE) with ethylene-vinyl alcohol (EVOH)-based NALEAs (Onyx and Squid) in acute bleeding outside of the neurovascular area. Materials and Methods: This study is a multicenter analysis of retrospectively collected data of consecutive patients who had undergone, from January 2015 to December 2022, transcatheter arterial embolization with non-adhesive EVOH-based agents in the setting of acute non-neurovascular bleeding. Results: Fifty-three patients underwent transcatheter arterial embolization for acute non-neurovascular bleeding. Eight (15.1%) procedures were performed in patients with coagulopathy. The most used concentration of EVOH-based NALEAs was 34 (i.e., 8%), with a mean dose of 0.5 (±0.3) mL. The mean CT-to-groin time, the mean procedure time, the mean CT-to-embolization time and the mean fluoroscopy time were 22.9 (±12.4) min, 27.5 (±7) min, 50.3 (±13.1) min and 7.5 (±2.8) min, respectively. Technical success was achieved in all cases with a 96.2% clinical success rate. Complications were recorded in six (11.3%) patients. No statistically significant differences were observed between the group of patients with coagulopathy and the group of patients without coagulopathy in terms of efficacy and safety endpoints. Conclusions: Transcatheter arterial embolization (TAE) performed with non-adhesive EVOH-based embolic agents is an effective, feasible and safe strategy for the management of acute non-neurovascular bleeding, even in the subgroup of patients with coagulopathy.

Embolic Materials: Understanding the Ocean of Choices

Embolization is a fundamental procedure that interventional radiologists perform on a daily basis to treat a variety of diseases. The disease processes for which embolization is considered a safe and effective treatment are continuously expanding, as are the embolization materials available for use. To achieve optimal clinical outcomes and minimize complications, it is imperative that the interventional radiologist understands the properties, strengths, and weaknesses of each class of embolic and specific embolic products. This is a continuous process as new materials are always becoming available. This article reviews the different classes of embolic materials, discusses strengths and weaknesses, and reviews areas of innovation.

Cost-Effectiveness Analysis of Transcatheter Arterial Embolization Techniques for the Treatment of Gastrointestinal Bleeding in the United States

OBJECTIVES

Gastrointestinal (GI) bleeding is a common medical emergency associated with significant mortality. Transcatheter arterial embolization first was introduced by Rosch et al as an alternative to surgery for upper GI bleeding. The clinical success in patients with GI bleeding treated with transcatheter arterial embolization previously has been reported. However, there are no cost-effectiveness analyses reported to date. Here we report cost-effectiveness analysis of N-butyl 2-cyanoacrylate glue (NBCA) and ethylene-vinyl alcohol copolymer (Onyx) versus coil (gold standard) for treatment of GI bleeding from a healthcare payer perspective.

METHODS

Fixed-effects modeling with a generalized linear mixed method was used in NBCA and coil intervention arms to determine the pooled probabilities of clinical success and mortality with complications with their confidence intervals, while the Clopper-Pearson model was used for Onyx to determine the same parameters. Models were provided by the "Meta-Analysis with R" software package. A decision tree was built for cost-effectiveness analysis, and Microsoft Excel was used for probabilistic sensitivity analysis. The cost-effective option was determined based on the incremental cost-effectiveness ratio and scatter plots of incremental cost versus incremental quality-adjusted life-years.

RESULTS

Comparing scatter plots and incremental cost-effectiveness ratio results, -$1024 and -$1349 per quality-adjusted life-year for Onyx and N-butyl 2-cyanoacrylate glue, respectively, Onyx was the least expensive and most effective intervention.

CONCLUSION

Onyx was the dominant strategy regardless of threshold values. Our analyses provide a framework for researchers to predict the target clinical effectiveness for early-stage TAE interventions and guide resource allocation decisions.

Upper Gastrointestinal Bleed Embolization with Onyx®: The "Tattoo Effect"

Endoscopic intervention is well validated for the control of upper gastrointestinal bleeding (UGIB). In cases of refractory bleeding, transarterial embolization is a safe and effective alternative. Ethylene vinyl alcohol (EVOH) commonly known as Onyx^® is an inherently black liquid embolic approved for use in cerebrovascular arteriovenous malformations and is increasingly used as an embolic agent in multiple peripheral and visceral territories. Onyx^® has a uniquely undesirable property of causing black color discoloration when used in peripheral applications adjacent to the skin akin to a "tattoo effect." Knowledge of the agents used by the interventional radiologist, clinical correlation, and close follow-up can be of paramount importance to avoid unnecessary surgical intervention. Here, we report a case demonstrating this "tattoo effect" on the gastric mucosa following UGIB embolization.